GM Series Data Guide Datasheet by Linx Technologies Inc.

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Lir'i)'(' TECHNOLOGIES Wireless made simple®
GM Series
GNSS Receiver Module
Data Guide
Table of Contents
1 Description
1 Features
1 Applications Include
2 Ordering Information
2 Absolute Maximum Ratings
2 ElectricalSpecifications
4 Pin Assignments
4 Pin Descriptions
5 A Brief Overview of GNSS
6 Time To First Fix (TTFF)
6 Module Description
7 Backup Battery
7 Power Supply Requirements
7 The 1PPS Output
7 Hybrid Ephemeris Prediction (AGPS)
8 Antenna Considerations
9 Power Control
10 Slow Start Time
11 Interfacing with NMEA Messages
12 NMEA Output Messages
19 Input Messages
40 Typical Applications
41 Microstrip Details
42 Board Layout Guidelines
43 Pad Layout
44 Production Guidelines
44 Hand Assembly
44 Automated Assembly
46 Master Development System
Warning: Some customers may want Linx radio frequency (“RF”)
products to control machinery or devices remotely, including machinery
or devices that can cause death, bodily injuries, and/or property
damage if improperly or inadvertently triggered, particularly in industrial
settings or other applications implicating life-safety concerns (“Life and
Property Safety Situations”).
NO OEM LINX REMOTE CONTROL OR FUNCTION MODULE
SHOULD EVER BE USED IN LIFE AND PROPERTY SAFETY
SITUATIONS. No OEM Linx Remote Control or Function Module
should be modified for Life and Property Safety Situations. Such
modification cannot provide sufficient safety and will void the product’s
regulatory certification and warranty.
Customers may use our (non-Function) Modules, Antenna and
Connectors as part of other systems in Life Safety Situations, but
only with necessary and industry appropriate redundancies and
in compliance with applicable safety standards, including without
limitation, ANSI and NFPA standards. It is solely the responsibility
of any Linx customer who uses one or more of these products to
incorporate appropriate redundancies and safety standards for the Life
and Property Safety Situation application.
Do not use this or any Linx product to trigger an action directly
from the data line or RSSI lines without a protocol or encoder/
decoder to validate the data. Without validation, any signal from
another unrelated transmitter in the environment received by the module
could inadvertently trigger the action.
All RF products are susceptible to RF interference that can prevent
communication. RF products without frequency agility or hopping
implemented are more subject to interference. This module does not
have a frequency hopping protocol built in.
Do not use any Linx product over the limits in this data guide.
Excessive voltage or extended operation at the maximum voltage could
cause product failure. Exceeding the reflow temperature profile could
cause product failure which is not immediately evident.
Do not make any physical or electrical modifications to any Linx
product. This will void the warranty and regulatory and UL certifications
and may cause product failure which is not immediately evident.
!
Lir'ix TECHNOLOG‘ES
– –
1
Description
The GM Series GNSS receiver module is
a self-contained high-performance Global
Satellite Navigation System receiver. Based on
the MediaTek chipset, it can simultaneously
acquire and track multiple satellite
constellations. These include the United States
GPS system, Europe’s GALILEO, Russia’s
GLONASS and Japan’s QZSS.
The module provides exceptional sensitivity,
even in dense foliage and urban canyons. It’s
very low power consumption helps maximize runtimes in battery powered
applications. Hybrid ephemeris prediction can be used to achieve cold start
times of less than 15 seconds. The module outputs standard NMEA data
through a UART interface.
Housed in a compact reflow-compatible SMD package, the receiver
requires no programming or additional RF components (except an antenna)
to form a complete GNSS solution. This makes the GM Series easy to
integrate, even by engineers without previous RF or GNSS experience.
Features
• MediaTek chipset
• High sensitivity (–161dBm)
• Fast TTFF at low signal levels
• Battery-backed SRAM
• 3-day ephemeris prediction
• No programming necessary
• No external RF components
needed (except an antenna)
• No production tuning
• UART serial interface
• Power control features
• Compact SMD package
Applications Include
• Positioning and Navigation
• Location and Tracking
• Security/Loss-Prevention
• Surveying
• Logistics
• Fleet Management
GM Series GNSS Receiver
Data Guide
Revised 10/20/2017
GNSS MODULE
RXM-GNSS-GM
LOT GRxxxx
0.591 in
(15.00 mm)
0.512 in
(13.00 mm)
0.087 in
(2.20 mm)
Figure 1: Package Dimensions
47 Appendix A
54 Notes
Warning: This product incorporates numerous static-sensitive
components. Always wear an ESD wrist strap and observe proper ESD
handling procedures when working with this device. Failure to observe
this precaution may result in module damage or failure.
– – – –
2 3
Ordering Information
Ordering Information
Part Number Description
RXM-GNSS-GM-x GM Series GNSS Receiver Module
MDEV-GNSS-GM GM Series GNSS Receiver Master Development System
EVM-GNSS-GM GM Series Evaluation Module
x = “T” for Tape and Reel, “B” for Bulk
Reels are 1,000 pieces. Quantities less than 1,000 pieces are supplied in bulk
Absolute Maximum Ratings
Supply Voltage VCC +4.3 VDC
Input Battery Backup Voltage +4.3 VDC
VOUT Output Current 50 mA
Operating Temperature –40 to +85 ºC
Storage Temperature –40 to +85 ºC
Exceeding any of the limits of this section may lead to permanent damage to the device.
Furthermore, extended operation at these maximum ratings may reduce the life of this
device.
Absolute Maximum Ratings
GM Series GNSS Receiver Specifications
Parameter Symbol Min. Typ. Max. Units Notes
Power Supply
Operating Voltage VCC 3.0 3.3 4.3 VDC
Supply Current lCC
Peak 150 mA 1, 2
Acquisition 24 mA 2
Tracking 16 mA 2
Standby 0.365 mA 2
Backup Battery Voltage VBAT 2.0 4.3 VDC
Backup Battery Current IBAT 7 µA 3
Antenna Port
RF Impedance RIN 50 Ω
ElectricalSpecifications
GM Series GNSS Receiver Specifications
Parameter Symbol Min. Typ. Max. Units Notes
VOUT Output Voltage VOUT 2.7 2.8 2.9 VDC
VOUT Output Current IOUT 30 mA 2
Output Low Voltage VOL 0.4 VDC
Output High Voltage VOH 2.4 3.3
Output Low Current IOL 2.0 mA
Output High Current IOH 2.0 mA
Input Low Voltage VIL –0.3 0.8 VDC
Input High Voltage VIH 2.0 3.6 VDC
Input Low Current IIL –1 1 µA 4
Input High Current IIH –1 1 µA 4
Minimum RESET Pulse TRST 1 ms
Receiver Section
Receiver Sensitivity
Tracking –161 dBm
Cold Start –143 dBm
Acquisition Time
Hot Start (Open Sky) 1 s
Hot Start (Indoor) 30 s
Cold Start 33 s
Cold Start, AGPS 15 s
Position Accuracy
Autonomous 3 m
SBAS 2.5 m
1PPS Accuracy –11 11 ns 5
Altitude 18,000 m
Velocity 515 m/s
Chipset MediaTek MT3333
Frequency GPS, GALILEO, QZSS: L1 1575.42MHz, C/A code
GLONASS: L1 1598.0625MHz ~ 1605.375MHz, C/A code
Channels 99
Update Rate 1Hz default, up to 10Hz
Protocol Support NMEA 0183 ver 4.10
Figure 2: Ordering Information
Figure 3: Absolute Maximum Ratings
Figure 4: Electrical Specifications
1. This is the current when dowloading AGPS data to the module
2. VCC = 3.3V, without active antenna, ephemeris prediction is off
3. VCC = 0V
4. No pull-up or pull-down on the lines
5. Relative to other GM Series modules, not to UTC time
– – – –
4 5
NC1
NC2
1PPS3
TX4
RX5
GND21
NC6
LCKIND7
RESET8
NC9
NC10
GND 20
RFIN 19
GND 18
VOUT 17
NC 16
GND 22
NC 15
NC 14
NC 13
VCC 12
VBACKUP 11
Pin Assignments
Pin Descriptions
Pin Descriptions
Pin Number Name I/O Description
1, 2, 6, 9, 10,
13, 14, 15, 16 NC No electrical connection
3 1PPS O 1 Pulse Per Second (11nS accuracy)
4 TX O Serial output (default NMEA)
5 RX I Serial input (default NMEA)
7 LCKIND O Lock Indicator. Outputs a 50ms pulse every
second when a GPS fix is available.
8 RESET I Active low module reset. This line is pulled high
internally. Leave it unconnected if it is not used.
11 VBACKUP P Backup battery supply voltage. This line must be
powered to enable the module.
12 VCC P Supply Voltage
17 VOUT O 2.8V output for an active antenna
18, 20, 21, 22 GND P Ground
19 RFIN I GNSS RF signal input
A Brief Overview of GNSS
Global Navigation Satellite System is a generic term that covers any system
of satellites that are used to determine location on Earth and have global
coverage. As of 2013 there are two fully operational GNSS systems;
NAVSTAR GPS operated by the United States and GLONASS operated
by Russia. The European Union is building its satellite constellation for their
Galileo system and China has started to expand their Beidou system into a
global system called Compass.
The United States has the original GNSS system consisting of a nominal
constellation of 24 satellites orbiting the earth at about 12,000 nautical
miles in height. The pattern and spacing of the satellites allow at least
four to be visible above the horizon from any point on the Earth. Russia’s
GLONASS system fell into disrepair after the collapse of the Soviet Union,
but was recovered and fully restored in 2011.
The systems were originally intended for military applications such as
ordinance delivery and troop movement. In 1994 when the NAVSTAR
constellation was completed, the GPS signals were made available for
civilian applications, primarily aircraft navigation.
Each satellite transmits low power radio signals which contain three
different bits of information; a pseudorandom code identifying the satellite,
ephemeris data which contains the current date and time as well as the
satellite’s precise orbit information, and the almanac data which tells where
each satellite should be at any time throughout the day and its status.
A receiver times the signals sent by multiple satellites and calculates the
distance to each satellite. If the position of each satellite is known, the
receiver can use triangulation to determine its position anywhere on the
earth. The receiver uses four satellites to solve for four unknowns; latitude,
longitude, altitude, and time. If any of these factors is already known to the
system, an accurate position (fix) can be obtained with fewer satellites in
view. Tracking more satellites improves calculation accuracy.
A faster Time To First Fix (TTFF) is possible if satellite information is stored
in the receiver. If the receiver knows some of this information, then it can
accurately predict satellite positions before acquiring an updated position
fix. For example, aircraft or marine navigation equipment may have other
means of determining altitude, so the GPS receiver would only have to
lock on to three satellites and calculate three equations to provide the first
position fix after power-up.
Figure 5: GM Series GNSS Receiver Pinout (Top View)
Figure 6: GM Series GNSS Receiver Pin Descriptions
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6 7
Time To First Fix (TTFF)
TTFF is often broken down into three parts:
Cold: A cold start is when the receiver has no accurate knowledge of its
position or time. This happens when the receiver’s internal Real Time Clock
(RTC) has not been running or it has no valid ephemeris or almanac data.
In a cold start, the receiver takes up to 30 seconds to acquire its position.
Warm: A typical warm start is when the receiver has valid almanac and time
data and has not significantly moved since its last valid position calculation.
This happens when the receiver has been shut down for more than 2
hours, but still has its last position, time, and almanac saved in memory,
and its RTC has been running. The receiver can predict the location of the
current visible satellites and its location; however, it needs to wait for an
ephemeris broadcast (every 30 seconds) before it can accurately calculate
its position.
Hot: A hot start is when the receiver has valid ephemeris, time, and
almanac data. In a hot start, the receiver takes 1 second to acquire its
position. The time to calculate a fix in this state is sometimes referred to as
Time to Subsequent Fix or TTSF.
Module Description
The GM Series GNSS Receiver module is based on the MediaTek MT3333
chipset, which consumes less power than competitive products while
providing exceptional performance even in dense foliage and urban
canyons. No external RF components are needed other than an antenna.
The simple serial interface and industry standard NMEA protocol make
integration of the GM Series into an end product extremely straightforward.
The module’s high-performance RF architecture allows it to receive GNSS
signals that are as low as –161dBm. The GM Series can track up to 33
satellites at the same time. Once locked onto the visible satellites, the
receiver calculates the range to the satellites and determines its position
and the precise time. It then outputs the data through a standard serial port
using several standard NMEA protocol formats.
The GNSS core handles all of the necessary initialization, tracking, and
calculations autonomously, so no programming is required. The RF section
is optimized for low level signals, and requires no production tuning.
Backup Battery
The module is designed to work with a backup battery that keeps the
SRAM memory and the RTC powered when the RF section and the main
GPS core are powered down. This enables the module to have a faster
Time To First Fix (TTFF) when it is powered back on. The memory and
clock pull about 7µA. This means that a small lithium battery is sufficient to
power these sections. This significantly reduces the power consumption
and extends the main battery life while allowing for fast position fixes when
the module is powered back on.
The backup battery must be installed for the module to be enabled.
Power Supply Requirements
The module requires a clean, well-regulated power source. While it is
preferable to power the unit from a battery, it can operate from a power
supply as long as noise is less than 20mV. Power supply noise can
significantly affect the receiver’s sensitivity, therefore providing clean power
to the module should be a high priority during design. Bypass capacitors
should be placed as close as possible to the module. The values should be
adjusted depending on the amount and type of noise present on the supply
line.
The 1PPS Output
The 1PPS line outputs 1 pulse per second on the rising edge of the GNSS
second when the receiver has an over-solved navigation solution from five
or more satellites. The pulse has a duration of 100ms by default with the
rising edge on the GNSS second. This line is low until the receiver acquires
a 3D fix. The pulse width can be adjusted with a serial command.
The GNSS second is based on the atomic clocks in the satellites, which
are monitored and set to Universal Time master clocks. This output and
the time calculated from the satellite transmissions can be used as a clock
feature in an end product with ±11ns accuracy.
Hybrid Ephemeris Prediction (AGPS)
AGPS is where the receiver uses the ephemeris data broadcast by the
satellites to calculate models of each visible satellite’s future location. This
allows the receiver to store up to 3 days’ worth of ephemeris data and
results in faster TTFF. Having this data reduces the cold start time to less
than 15 seconds. Contact Linx for details on this.
Cam 5m
– – – –
8 9
Antenna Considerations
The GM Series module is designed to utilize a wide variety of external
antennas. The module has a regulated power output which simplifies the
use of GNSS antenna styles which require external power. This allows
the designer great flexibility, but care must be taken in antenna selection
to ensure optimum performance. For example, a handheld device may
be used in many varying orientations so an antenna element with a wide
and uniform pattern may yield better overall performance than an antenna
element with high gain and a correspondingly narrower beam. Conversely,
an antenna mounted in a fixed and predictable manner may benefit from
pattern and gain characteristics suited to that application. Evaluating
multiple antenna solutions in real-world situations is a good way to rapidly
assess which will best meet the needs of your application.
For GNSS, the antenna should have good right hand circular polarization
characteristics (RHCP) to match the polarization of the GNSS signals.
Ceramic patches are the most commonly used style of antenna, but
there are many different shapes, sizes and styles of antennas available.
Regardless of the construction, they will generally be either passive or
active types. Passive antennas are simply an antenna tuned to the correct
frequency. Active antennas add a Low Noise Amplifier (LNA) after the
antenna and before the module to amplify the weak GPS satellite signals.
For active antennas, a 300 ohm ferrite bead can be used to connect the
VOUT line to the RFIN line. This bead prevents the RF from getting into the
power supply, but allows the DC voltage onto the RF trace to feed into the
antenna. A series capacitor inside the module prevents this DC voltage
from affecting the bias on the module’s internal LNA.
Maintaining a 50 ohm path between the module and antenna is critical.
Errors in layout can significantly impact the module’s performance. Please
review the layout guidelines section carefully to become more familiar with
these considerations.
Power Control
The GM Series GPS Receiver module offers several ways to control the
module’s power. A serial command puts the module into a low-power
standby mode that consumes only 365µA of current. An external processor
can be used to power the module on and off to conserve battery power.
In addition, the module includes a duty cycle mode where the module will
power on for a configurable amount of time to obtain a position fix then
power off for a configurable amount of time. In this way the module can
handle all of the timing without any intervention from the external processor.
There are four times that are configured with duty cycle mode. The on
time and standby times are the amount of times that the module is on and
in standby in normal operation. There are also cold start on and standby
times. These are used to keep the module on longer in the event of a cold
start so that it can gather the required satellite data for a position fix. After
this, the module uses the normal operation times.
In the event that the module’s stored ephemeris data becomes invalid the
module supports and extended receive time to gather the required data
from the satellites. Figure 7 shows the power control times.
The module supports MediaTek’s proprietary AlwaysLocateTM mode. In
this mode, the module automatically adapts the on and standby times to
the current environmental conditions to balance position accuracy and
power consumption. In this mode, any byte sent to the module triggers it to
output the current position data.
Standby mode is configured by command 161. Extended receive time is
configured by command 223. Command 225 configures which duty cycle
mode is used.
Only enter standby mode after the module acquires a position fix.
ON
Standby
Cold Start On Time
Cold Start
Standby Time Standby TimeOn Time On Time Extended RX Time
Figure 7: GM Series GNSS Receiver Power Control
– – – –
10 11
Slow Start Time
The most critical factors in start time are current ephemeris data, signal
strength and sky view. The ephemeris data describes the path of each
satellite as they orbit the earth. This is used to calculate the position of
a satellite at a particular time. This data is only usable for a short period
of time, so if it has been more than a few hours since the last fix or if the
location has significantly changed (a few hundred miles), then the receiver
may need to wait for a new ephemeris transmission before a position can
be calculated. The GNSS satellites transmit the ephemeris data every 30
seconds. Transmissions with a low signal strength may not be received
correctly or be corrupted by ambient noise. The view of the sky is important
because the more satellites the receiver can see, the faster the fix and the
more accurate the position will be when the fix is obtained.
If the receiver is in a very poor location, such as inside a building, urban
canyon, or dense foliage, then the time to first fix can be slowed. In very
poor locations with poor signal strength and a limited view of the sky with
outdated ephemeris data, this could be on the order of several minutes.
In the worst cases, the receiver may need to receive almanac data, which
describes the health and course data for every satellite in the constellation.
This data is transmitted every 15 minutes. If a lock is taking a long time, try
to find a location with a better view of the sky and fewer obstructions. Once
locked, it is easier for the receiver to maintain the position fix.
Interfacing with NMEA Messages
Linx modules default to the NMEA protocol. Output messages are sent
from the receiver on the TX line and input messages are sent to the receiver
on the RX line. By default, output messages are sent once every second.
Details of each message are described in the following sections.
The NMEA message format is as follows: <Message-ID + Data Payload +
Checksum + End Sequence>. The serial data structure defaults to
9,600bps, 8 data bits, 1 start bit, 1 stop bit, and no parity. Each message
starts with a $ character and ends with a <CR> <LF>. All fields within
each message are separated by a comma. The checksum follows the *
character and is the last two characters, not including the <CR> <LF>.
It consists of two hex digits representing the exclusive OR (XOR) of all
characters between, but not including, the $ and * characters. When
reading NMEA output messages, if a field has no value assigned to it, the
comma will still be placed following the previous comma. For example,
{,04,,,,,2.0,} shows four empty fields between values 04 and 2.0. When
writing NMEA input messages, all fields are required, none are optional. An
empty field will invalidate the message and it will be ignored.
Reading NMEA output messages:
• Initialize a serial interface to match the serial data structure of the GPS
receiver.
• Read the NMEA data from the TX pin into a receive buffer.
• Separate it into six buffers, one for each message type. Use the
characters ($) and <CR> <LF> as end points for each message.
• For each message, calculate the checksum as mentioned above to
compare with the received checksum.
• Parse the data from each message using commas as field separators.
• Update the application with the parsed field values.
• Clear the receive buffer and be ready for the next set of messages.
Writing NMEA input messages:
• Initialize a serial interface to match the serial data structure of the GPS
receiver.
• Assemble the message to be sent with the calculated checksum.
• Transmit the message to the receiver on the RX line.
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12 13
NMEA Output Messages
The following sections outline the data structures of the various NMEA
messages that are supported by the module. By default, the NMEA
commands are output at 9,600bps, 8 data bits, 1 start bit, 1 stop bit, and
no parity.
Six messages are output at a 1Hz rate by default. The ZDA message is
supported, but disabled by default. These messages are shown in Figure 8.
Some of the message IDs can change based on which system is used for
the position fix. Figure 9 shows the different message identifiers based on
the system that is used.
Details of each message and examples are given in the following sections.
GGA – Global Positioning System Fix Data
Figure 10 contains the values for the following example:
$GPGGA,053740.000,2503.6319,N,12136.0099,E,1,08,1.1,63.8,M,15.2,M,,0000*64
Global Positioning System Fix Data Example
Name Example Units Description
Message ID $GPGGA GGA protocol header
UTC Time 053740.000 hhmmss.sss
Latitude 2503.6319 ddmm.mmmm
N/S Indicator N N=north or S=south
Longitude 12136.0099 dddmm.mmmm
E/W Indicator E E=east or W=west
Position Fix Indicator 1 See Figure 11
Satellites Used 08 Range 0 to 33
HDOP 1.1 Horizontal Dilution of Precision
MSL Altitude 63.8 meters
Units M meters
Geoid Separation 15.2 meters
Units M meters
Age of Diff. Corr. second Null fields when DGPS is not used
Diff. Ref. Station 0000
Checksum *64
<CR> <LF> End of message termination
Position Indicator Values
Value Description
0 Fix not available or invalid
1 GPS SPS Mode, fix valid
2 Differential GPS, SPS Mode, fix valid
3–5 Not supported
6 Dead Reckoning Mode, fix valid (requires external hardware)
NMEA Output Message Identifiers
System GGA GLL GSA GSV RMC VTG
GPS GPGGA GPGLL GPGSA GPGSV GPRMC GPVTG
GPS &
GLONASS GPGGA GNGLL GNGSA GPGSV
GLGSV
GPRMC or
GNRMC1GPVTG
1. The RMC output is GPRMC before a 3D fix, then changes to GNRMC after a fix is
locked.
Figure 10: Global Positioning System Fix Data Example
Figure 11: Position Indicator Values
NMEA Output Messages
Name Description
GGA Contains the essential fix data which provide location and accuracy
GLL Contains just position and time
GSA Contains data on the Dilution of Precision (DOP) and which satellites are used
GSV
Contains the satellite location relative to the receiver and its signal to noise
ratio. Each message can describe 4 satellites so multiple messages may be
output depending on the number of satellites being tracked.
RMC Contains the minimum data of time, position, speed and course
VTG Contains the course and speed over the ground
ZDA Contains the date and time
Figure 8: NMEA Output Messages
Figure 9: NMEA Output Message Identifiers
– – – –
14 15
GSV – GNSS Satellites in View
Figure 15 contains the values for the following example:
$GPGSV,3,1,12,28,81,285,42,24,67,302,46,31,54,354,,20,51,077,46*73
$GPGSV,3,2,12,17,41,328,45,07,32,315,45,04,31,250,40,11,25,046,41*75
$GPGSV,3,3,12,08,22,214,38,27,08,190,16,19,05,092,33,23,04,127,*7B
$GLGSV,2,1,07,76,71,201,44,65,57,041,40,75,48,028,39,72,27,108,39*68
$GLGSV,2,2,07,66,25,333,43,77,17,207,37,81,02,280,29*5C
GLL – Geographic Position – Latitude / Longitude
Figure 12 contains the values for the following example:
$GPGLL,2503.6319,N,12136.0099,E,053740.000,A,A*52
GSA – GNSS DOP and Active Satellites
Figure 13 contains the values for the following example:
$GPGSA,A,3,24,07,17,11,28,08,20,04,,,,,2.0,1.1,1.7*35
GNSS DOP and Active Satellites Example
Name Example Units Description
Message ID $GPGSA GSA protocol header (GPGSA for GPS
or GNGSA for GLONASS)
Mode 1 A See Figure 14
Mode 2 3 1=No fix, 2=2D, 3=3D
ID of satellite used 24 Sv on Channel 1
ID of satellite used 07 Sv on Channel 2
... ...
ID of satellite used Sv on Channel N
PDOP 2.0 Position Dilution of Precision
HDOP 1.1 Horizontal Dilution of Precision
VDOP 1.7 Vertical Dilution of Precision
Checksum *35
<CR> <LF> End of message termination
Geographic Position – Latitude / Longitude Example
Name Example Units Description
Message ID $GPGLL GLL protocol header (GNGLL or
GPGLL)
Latitude 2503.6319 ddmm.mmmm
N/S Indicator N N=north or S=south
Longitude 12136.0099 dddmm.mmmm
E/W Indicator E E=east or W=west
UTC Time 053740.000 hhmmss.sss
Status A A=data valid or V=data not valid
Mode A A=autonomous, D=DGPS, N=Data not
valid, R=Coarse Position, S=Simulator
Checksum *52
<CR> <LF> End of message termination
Mode 1 Values
Value Description
M Manual – forced to operate in 2D or 3D mode
A Automatic – allowed to automatically switch 2D/3D
GNSS Satellites in View Example
Name Example Units Description
Message ID $GPGSV GSV protocol header (GPGSV for GPS and
GLGSV for GLONASS)
Total number of
messages13 Range 1 to 6 (GPS) and 1 to 3 (GLONASS)
Message number11 Range 1 to 6 (GPS) and 1 to 3 (GLONASS)
Satellites in view 12
Satellite ID 28 Channel 1 (Range 01 to 196)
Elevation 81 degrees Channel 1 (Range 00 to 90)
Azimuth 285 degrees Channel 1 (Range 000 to 359)
SNR (C/No) 42 dB–Hz Channel 1 (Range 00 to 99, null when not
tracking)
Satellite ID 20 Channel 2 (Range 01 to 196)
Elevation 51 degrees Channel 2 (Range 00 to 90)
Azimuth 077 degrees Channel 2 (Range 000 to 359)
SNR (C/No) 46 dB-Hz Channel 2 (Range 00 to 99, null when not
tracking.
Checksum *73
<CR> <LF> End of message termination
1. Depending on the number of satellites tracked, multiple messages of GSV data
may be required.
Figure 12: Geographic Position – Latitude / Longitude Example
Figure 13: GNSS DOP and Active Satellites Example
Figure 14: Mode 1 Values
Figure 15: GNSS Satellites in View Example
– – – –
16 17
RMC – Recommended Minimum Specific GNSS Data
Figure 16 contains the values for the following example:
$GPRMC,053740.000,A,2503.6319,N,12136.0099,E,2.69,79.65,100106,,,A*53
Recommended Minimum Specific GNSS Data Example
Name Example Units Description
Message ID $GPRMC RMC protocol header (GNRMC or
GPRMC)
UTC Time 053740.000 hhmmss.sss
Status A A=data valid or V=data not valid
Latitude 2503.6319 ddmm.mmmm
N/S Indicator N N=north or S=south
Longitude 12136.0099 dddmm.mmmm
E/W Indicator E E=east or W=west
Speed over ground 2.69 knots TRUE
Course over ground 79.65 degrees
Date 100106 ddmmyy
Magnetic Variation degrees Not available, null field
Variation Sense E=east or W=west (not shown)
Mode A
A=autonomous, D=DGPS, E=DR, N=
Data not valid, R=Coarse Position,
S=Simulator
Checksum *53
<CR> <LF> End of message termination
VTG – Course Over Ground and Ground Speed
Figure 17 contains the values for the following example:
$GPVTG,79.65,T,,M,2.69,N,5.0,K,A*38
Course Over Ground and Ground Speed Example
Name Example Units Description
Message ID $GPVTG VTG protocol header
Course over ground 79.65 degrees Measured heading
Reference T TRUE
Course over ground degrees Measured heading (N/A, null field)
Reference M Magnetic
Speed over ground 2.69 knots Measured speed
Units N Knots
Speed over ground 5.0 km/hr Measured speed
Units K Kilometer per hour
Mode A
A=autonomous, D=DGPS, N=
Data not valid, R=Coarse Position,
S=Simulator
Checksum *38
<CR> <LF> End of message termination
Figure 16: Recommended Minimum Specific GNSS Data Example
Figure 17: Course Over Ground and Ground Speed Example
– – – –
18 19
ZDA – Universal Time and Date
Figure 18 contains the values for the following example:
$GPZDA,183746.000,22,08,2014,,*56
Start-up Response
The module outputs a message when it starts up to indicate its state. The
normal start-up message is shown below and the message formatting is
shown in Figure 19.
$PMTK010,001*2E<CR><LF>
Universal Time and Date Example
Name Example Units Description
Message ID $GPZDA ZDA protocol header
UTC Time 183746.000 hhmmss.sss
Day 22 01 to 31
Month 08 01 to 12
Year 2014 1980 to 2079
Local Zone Hour Offset from UTC; set to null
Local Zone Minutes Offset from UTC; set to null
Checksum *56
<CR> <LF> End of message termination
Figure 18: Universal Time and Date Example
Start-up Response Example
Name Example Description
Message ID $PMTK010 Message header
Message
MSG
System Message
0 = Unknown
1 = Start-up
2 = Notification for the host supporting EPO
3 = Transition to Normal operation is successful
Checksum CKSUM
End Sequence <CR> <LF> End of message termination
Figure 19: Start-up Response Example
PMTKLSC - Leap Second Change
Figure 10 contains the values for the following example:
$PMTKLSC,17,0,17*42
Once the leap second has been updated from the satellite transmissions,
the indicator field changes to 1. At this point, the indicator is accurate.
$PMTKLSC,17,1,17*43
Figure 20: Leap Second Change Example
Leap Second Change Example
Name Example Units Description
Message ID $PMTKLSC Leap Second Change protocol header
Current 17 Current leap second
Indicator 0 Leap indicator, 1 = updated from
broadcast data
Next 17 Next leap second
Checksum *42
<CR> <LF> End of message termination
– – – –
20 21
The write and read messages are shown in Figure 23. A write message
triggers an acknowledgement from the module. A read message triggers a
response message containing the requested information.
Input Write and Read Messages
Description Write ID Read ID Response ID
DGPS Source 301 401 501
SBAS Enable 313 413 513
NMEA Output Messages 314 414 514
Set Datum 330 430 530
GNSS Search System 353
Static Navigation Threshold 386 447 527
Enable Ephemeris Prediction 869 869 869
Figure 22: Input Commands
Input Commands
Name Description
101 Hot Re-start
102 Warm Re-start
103 Cold Re-start
104 Restore Default Configuration
161 Standby Mode
220 Position Fix Interval
223 Extended Receive Time
225 Receiver Duty Cycle
251 Serial Port Baud Rate
255 Sync 1PPS and NMEA Messages
256 Set Timing Product
257 Set Tunnel Scenario
285 1PPS Configuration
286 Enable Active Interference Cancellation
875 Enable Leap Second Change Message
Figure 23: Input Write and Read Messages
Input Messages
The following outlines the serial commands input into the module for
configuration. There are 3 types of input messages: commands, writes and
reads. The module outputs a response for each input message.
The commands are used to change the operating state of the module.
The writes are used to change the module’s configuration and the reads
are used to read out the current configuration. Messages are formatted as
shown in Figure 21. All fields in each message are separated by a comma.
Figure 22 shows the input commands.
Serial Data Structure
Name Example Description
Start Sequence $PMTK
Message ID <MID> Message Identifier consisting of three numeric
characters.
Payload DATA Message specific data.
Checksum CKSUM
CKSUM is a two-hex character checksum as
defined in the NMEA specification, NMEA-0183
Standard for Interfacing Marine Electronic Devices.
Checksums are required on all input messages.
End Sequence <CR> <LF>
Each message must be terminated using Carriage
Return (CR) Line Feed (LF) (\r\n, 0x0D0A) to cause
the receiver to process the input message. They
are not printable ASCII characters, so are omitted
from the examples.
Figure 21: Serial Data Structure
– – – –
22 23
The module responds to commands with response messages. The
acknowledge message is formatted as shown in Figure 24.
101 – Hot Re-start
This command instructs the module to conduct a hot re-start using all of
the data stored in memory. Periodic mode and static navigation settings are
returned to default when this command is executed.
$PMTK101*32<CR><LF>
102 – Warm Re-start
This command instructs the module to conduct a warm re-start that does
not use the saved ephemeris data. Periodic mode and static navigation
settings are returned to default when this command is executed.
$PMTK102*31<CR><LF>
103 – Cold Re-start
This command instructs the module to conduct a cold re-start that does
not use any of the data from memory. Periodic mode and static navigation
settings are returned to default when this command is executed.
$PMTK103*30<CR><LF>
Acknowledge Message
Name Example Description
Start Sequence $PMTK
Message ID 001 Acknowledge Identifier
Command CMD The command that triggered the acknowledge
Flag Flg
Flag indicating the outcome of the command
0 = Invalid Command
1 = Unsupported Command
2 = Valid command, but action failed
3 = Valid command and action succeeded
Checksum CKSUM
CKSUM is a two-hex character checksum as
defined in the NMEA specification, NMEA-0183
Standard for Interfacing Marine Electronic Devices.
Checksums are required on all input messages.
End Sequence <CR> <LF>
Each message must be terminated using Carriage
Return (CR) Line Feed (LF) (\r\n, 0x0D0A) to cause
the receiver to process the input message. They
are not printable ASCII characters, so are omitted
from the examples.
Figure 24: Acknowledge Message
104 – Restore Default Configuration
This command instructs the module to conduct a cold re-start and return
all configurations to the factory default settings.
$PMTK104*37<CR><LF>
161 – Standby Mode
This command instructs the module to enter a low power standby mode.
Any activity on the RX line wakes the module. Only enter standby mode
after the module acquires a position fix.
$PMTK161,0*28<CR><LF>
The module outputs the startup message when it wakes up.
$PMTK010,001*2E<CR><LF>
220 – Position Fix Interval
This command sets the position fix interval. This is the time between when
the module calculates its position.
Ival = the interval time in milliseconds.
The interval must be larger than 100ms. Faster rates require that the baud
rate be increased, the number of messages that are output be decreased
or both. The module automatically calculates the required data bandwidth
and returns an action failed response (Flg = 2) if the interval is faster than
the module can output all of the required messages at the current baud
rate. The following example sets the interval to 1 second.
$PMTK220,1000*1F<CR><LF>
It is recommended to use interval rates of 100ms, 200ms, 500ms,
1,000ms and 2,000ms. Although permissible, non-standard intervals are
not guaranteed or recommended.
Position Fix Interval Command and Response
Command
Start Msg ID Interval Checksum End
$PMTK 220 ,Ival *Cksum <CR><LF>
Response
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,220 ,Flg *Cksum <CR><LF>
Figure 25: Position Fix Interval Command and Response
– – – –
24 25
223 – Extended Receive Time
This command extends the amount of time that the receiver is on when in
duty cycle mode. This allows the module to refresh its stored ephemeris
data by staying awake until it received the data from the satellites.
The following example configures an extended on time to trigger if less
than 1 satellite has valid ephemeris data. The satellite must have a signal to
noise ratio higher than 30dB–Hz in order to be used. The module will stay
on for 180,000ms and will have a gap time of 60,000ms.
$PMTK223,1,30,180000,60000*16<CR><LF>
Extended Receive Time Command and Response
Command
Start Msg ID SV On
Time
Extend
Time
Extend
Gap Checksum End
$PMTK 223 ,SV ,SNR ,EXT ,EXG *Cksum <CR><LF>
Response
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,223 ,Flg *Cksum <CR><LF>
Figure 26: Extended Receive Time Command and Response
Extended Receive Time Fields
Field Description
SV
The minimum number of satellites required to have valid ephemeris data. The
extend time triggers when the number of satellites with valid ephemeris data
falls below this number. The value is 1 to 4.
SNR The minimum SNR of the satellites used for a position fix. The module will not
wait for ephemeris data from any satellites whose SNR is below this value.
EXT The extended time in ms to stay on to receive ephemeris data. This value can
range from 40000 to 180000.
EXG The minimum time in ms between a subsequent extended receive period. This
value can range from 0 to 3600000.
Figure 27: Extended Receive Time Fields
225 – Receiver Duty Cycle
This command places the module into a duty cycle where it stays on for
a period of time and calculates it position then goes to sleep for a period
of time. This conserves battery power without the need for an external
microcontroller to manage the timing.
This example sets the mode to duty cycle with an on time of 3s, and off
time of 12s, a cold start on time of 18s and a cold start off time of 72s.
$PMTK225,2,3000,12000,18000,72000*15<CR><LF>
The following example sets the mode to normal operation.
$PMTK225,0*2B<CR><LF>
The following example sets the module into AlwaysLocateTM mode.
$PMTK225,8*23<CR><LF>
Receiver Duty Cycle Command and Response
Command
Start Msg ID Mode On
Time
Standby
Time Cold On Cold
Sleep Checksum End
$PMTK 225 ,Mde ,TO ,TS ,CO ,CS *Cksum <CR><LF>
Response
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,225 ,Flg *Cksum <CR><LF>
Figure 28: Receiver Duty Cycle Command and Response
Receiver Duty Cycle Fields
Field Description
Mde
Operation Mode
0 = Normal Mode
2 = Duty Cycle Mode
8 = AlwaysLocateTM
TO Receiver on time (ms)
TS Receiver standby time (ms)
CO Receiver on time in the event of a cold start (ms). Allows more time for
the module to receive ephemeris data in the event of a cold start.
CS Receiver off time in the event of a cold start (ms). Allows more time for
the module to receive ephemeris data in the event of a cold start.
CO and CS can be null values. In this case the module uses the TO and TS values.
Figure 29: Receiver Duty Cycle Fields
– – – –
26 27
251 – Serial Port Baud Rate
This command sets the serial port baud rate.
Rate = serial port baud rate
0 = default setting
4800
9600
14400
19200
38400
57600
115200
The following example sets the serial port baud rate to 57,600bps.
$PMTK251,57600*2C<CR><LF>
Serial Port Baud Rate Command and Response
Command
Start Msg ID Rate Checksum End
$PMTK 251 ,Rate *Cksum <CR><LF>
Response
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,251 ,Flg *Cksum <CR><LF>
Figure 30: Serial Port Baud Rate Command and Response
255 – Sync 1PPS and NMEA Messages
This command enables or disables synchronization between the 1PPS
pulse and the NMEA messages. When enabled, the beginning of the
NMEA message on the UART is fixed to between 465 and 485ms after the
rising edge of the 1PPS pulse. The NMEA message describes the position
and time as of the rising edge of the 1PPS pulse.
This is only supported at a 1Hz NMEA message rate. It is disabled
by default. If all six NMEA messages are output, the serial port baud
rate should be between 19,200 and 115,200bps to ensure stable
synchronization.
The following examples show the use of this command.
Enable Sync: $PMTK255,1*2D<CR><LF>
Disable Sync: $PMTK255,0*2C<CR><LF>
Sync 1PPS and NMEA Messages Command and Response
Command
Start Msg ID Enable Checksum End
$PMTK 255 ,Enable *Cksum <CR><LF>
Response
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,255 ,Flg *Cksum <CR><LF>
Figure 31: Sync 1PPS and NMEA Messages Command and Response
UTC 12:00:00 UTC 12:00:01
1PPS
TX
465ms ~ 485ms
UTC 12:00:00 UTC 12:00:01
Figure 32: 1PPS and NMEA Message Synchronization
– – – –
28 29
256 – Set Timing Product
This command enables or disables the timing product. The timing product
improves the accuracy of the 1PPS pulse relative to other modules.
This command needs to be sent again after hot, warm or cold starts or
after waking from standby mode.
The following examples show the use of this command.
Enable Timing Product: $PMTK256,1*2E<CR><LF>
Disable Timing Product: $PMTK256,0*2F<CR><LF>
The set timing protocol configuration returns to the default values after a
reset or restart.
Set Timing Product Command and Response
Command
Start Msg ID Enable Checksum End
$PMTK 256 ,Enable *Cksum <CR><LF>
Response
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,256 ,Flg *Cksum <CR><LF>
Figure 33: Set Timing Product Command and Response
257 – Set Tunnel Scenario
This command enables a fast time to first fix or high position accuracy
when emerging from a tunnel.
Type = Type of position fix
0 = Fast TTFF
1 = High Accuracy (default)
The following examples show the use of this command.
Enable fast TTFF: $PMTK257,0*2E<CR><LF>
Enable high accuracy: $PMTK257,1*2F<CR><LF>
Set Tunnel Scenario Command and Response
Command
Start Msg ID Type Checksum End
$PMTK 257 ,Type *Cksum <CR><LF>
Response
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,257 ,Flg *Cksum <CR><LF>
Figure 34: Set Tunnel Scenario Command and Response
– – – –
30 31
285 – 1PPS Configuration
This command configures the 1PPS output.
Figure 36 shows the Type values.
The Width field is the width of the 1PPS pulse in milliseconds. The max
width is 900ms at a 1Hz NMEA message rate. The default is 100ms.
These configurations are maintained during hot and warm starts, but are
lost on cold starts and restore to factory defaults.
Set the 1PPS to activate after a 3D fix and have a 10ms pulse width.
$PMTK285,2,10*0E<CR><LF>
Set the 1PPS to activate after a 3D fix and have a 900ms pulse width.
$PMTK285,2,900*36<CR><LF>
1PPS Configuration Command and Response
Command
Start Msg ID Type Pulse Width Checksum End
$PMTK 285 ,Type ,Width *Cksum <CR><LF>
Response
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,285 ,Flg *Cksum <CR><LF>
Figure 35: 1PPS Configuration Messages Command and Response
1PPS Configuration Type Values
Value Description
0 Disable
1 After the first fix
2 3D fix only (default)
3 2D/3D fix only
4 Always
Figure 36: 1PPS Configuration Type Values
286 – Enable Active Interference Cancellation
This command enables or disables active interference cancellation. This
feature helps remove jamming and narrow-band interference to enable a
position fix.
By default, this is enabled after the first fix is acquired.
The following examples show the use of this command.
Enable: $PMTK286,1*23<CR><LF>
Disable: $PMTK286,0*22<CR><LF>
Enable Active Interference Cancellation Command and Response
Command
Start Msg ID Enable Checksum End
$PMTK 286 ,Enable *Cksum <CR><LF>
Response
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,286 ,Flg *Cksum <CR><LF>
Figure 37: Enable Active Interference Cancellation Messages Command and Response
– – – –
32 33
DGPS Source
This enables or disables DGPS mode and configures its source.
Mode = DGPS source mode
0 = No DGPS source
1 = RTCM
2 = WAAS
Differential Global Positioning System (DGPS) enhances GPS by using
fixed, ground-based reference stations that broadcast the difference
between the positions indicated by the satellite systems and the known
fixed positions. The Radio Technical Commission for Maritime Services
(RTCM) is an international standards organization that has a standard for
DGPS. Wide Area Augmentation System (WAAS) is maintained by the FAA
to improve aircraft navigation. This setting automatically switches among
WAAS, EGNOS, MSAS and GAGAN when detected in covered regions
The following example sets the DGPS source to RTCM.
$PMTK301,1*2D<CR><LF>
The following example reads the current DGPS source and the module
responds with the DGPS source as RTCM.
$PMTK401*37<CR><LF>
$PMTK501,1*2B<CR><LF>
DGPS Souce Command and Response
Write Message
Start Msg ID Mode Checksum End
$PMTK 301 ,Mode *Cksum <CR><LF>
Acknowledge Response Message
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,301 ,Flg *Cksum <CR><LF>
Read Message
Start Msg ID Checksum End
$PMTK 401 *37 <CR><LF>
Response Message
Start Msg ID Mode Checksum End
$PMTK 501 ,Mode *Cksum <CR><LF>
Figure 41: DGPS Source Command and Response
875 – Enable PMTKLSC Message
This command enables or disables the Leap Second Change message.
The following examples show the use of this command.
Enable PMTKLSC: $PMTK875,1,1*38<CR><LF>
Disable PMTKLSC: $PMTK875,1,0*39<CR><LF>
Query PMTKLSC: $PMTK875,0*24<CR><LF>
Query Response: $PMTK875,2,0*3A<CR><LF> (Message disabled)
Enable PMTKLSC Message Command and Response
Command
Start Msg ID CmdType Enable Checksum End
$PMTK 875 ,CmdType ,Enable *Cksum <CR><LF>
Set Response
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,875 ,Flg *Cksum <CR><LF>
Query Response
Start Msg ID CmdType Enable Checksum End
$PMTK 875 ,2 ,Enable *Cksum <CR><LF>
Figure 38: Sync 1PPS and NMEA Messages Command and Response
CmdType Values
Value Description
0 Query
1 Set
2 Result of the Query Operation
Figure 39: CmdType Values
Enable Values
Value Description
0 Message Disabled
1 Message Enabled
Figure 40: CmdType Values
– – – –
34 35
SBAS Enable
This enables and disables SBAS.
Mode = SBAS Mode
0 = disabled
1 = enabled
A satellite-based augmentation system (SBAS) sends additional information
in the satellite transmissions to improve accuracy and reliability. Ground
stations at accurately surveyed locations measure the satellite signals or
other environmental factors that may impact the signal received by users.
Correction information is then sent to the satellites and broadcast to the
users. Disabling this feature also disables automatic DGPS.
The following example enables SBAS.
$PMTK313,1*2E<CR><LF>
The following example reads the current SBAS configuration and the
module responds with SBAS is enabled.
$PMTK413*34<CR><LF>
$PMTK513,1*28<CR><LF>
SBAS Enable Command and Response
Write Message
Start Msg ID Mode Checksum End
$PMTK 313 ,Mode *Cksum <CR><LF>
Acknowledge Response Message
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,313 ,Flg *Cksum <CR><LF>
Read Message
Start Msg ID Checksum End
$PMTK 413 *34 <CR><LF>
Response Message
Start Msg ID Mode Checksum End
$PMTK 513 ,Mode *Cksum <CR><LF>
Figure 42: SBAS Enable Command and Response
NMEA Output Messages
This configures how often each NMEA output message is output.
Each field has a value of 1 through 5 which indicates how many position
fixes should be between each time the message is output. A 1 configures
the message to be output every position fix. A value of 2 configures the
message to be output every other position fix and a value of 5 configures
it to be output every 5th position fix. This along with message 220 sets the
time between message outputs.
A value of 0 disables the message.
The example below sets all of the messages to be output every fix.
$PMTK314,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,1,0*29<CR><LF>
The following example reads the current message configuration and the
module responds that all supported messages are configured to be output
on every position fix.
$PMTK414*33<CR><LF>
$PMTK514,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,1,0*2F<CR><LF>
NMEA Output Messages Command and Response
Write Message
Start Msg
ID GLL RMC VTG GGA GSA GSV DATA ZDA 0 CK End
$PMTK 314 ,GLL ,RMC ,VTG ,GGA ,GSA ,GSV ,0,0,0,0,0,0,0,0,0,0,0 ,ZDA ,0 *CK <CR><LF>
Acknowledge Response Message
Start Msg
ID CMD Flag CK End
$PMTK 001 ,314 ,Flg *CK <CR><LF>
Read Message
Start Msg
ID CK End
$PMTK 414 *33 <CR><LF>
Response Message
Start Msg
ID GLL RMC VTG GGA GSA GSV DATA ZDA 0 CK End
$PMTK 514 ,GLL ,RMC ,VTG ,GGA ,GSA ,GSV ,0,0,0,0,0,0,0,0,0,0,0 ,ZDA ,0 *CK <CR><LF>
Figure 43: NMEA Output Messages Command and Response
– – – –
36 37
Set Datum
This configures the current datum that is used.
Datum = the datum number to be used.
Reference datums are data sets that describe the shape of the Earth
based on a reference point. There are many regional datums based on a
convenient local reference point. Different datums use different reference
points, so a map used with the receiver output must be based on the same
datum. WGS84 is the default world referencing datum.
The module supports 223 different datums. These are listed in Appendix A.
The following example sets the datum to WGS84.
$PMTK330,0*2E<CR><LF>
The following example reads the current datum and the module replies with
datum 0, which is WGS84.
$PMTK430*35<CR><LF>
$PMTK530,0*28<CR><LF>
Set Datum Command and Response
Write Message
Start Msg ID Datum Checksum End
$PMTK 330 ,Datum *Cksum <CR><LF>
Acknowledge Response Message
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,330 ,Flg *Cksum <CR><LF>
Read Message
Start Msg ID Checksum End
$PMTK 430 *35 <CR><LF>
Response Message
Start Msg ID Datum Checksum End
$PMTK 530 ,Datum *Cksum <CR><LF>
Figure 44: Set Datum Command and Response
GNSS Search System
This configures the GNSS systems used to calculate position fixes.
GPS = Search GPS satellites
0 = disabled, do not search GPS satellites
1 = enabled
GLNS = Search GLONASS satellites
0 = disabled, do not search GLONASS satellites
1 = enabled
GAL = Search GALILEO satellites (not supported, set to 0)
GALF = Search GALILEO full mode satellites (not supported, set to 0)
BEI = Search Beidou satellites (not supported, set to 0)
The following example configures the module to only use GLONASS
satellites.
$PMTK353,0,1,0,0,0*2A<CR><LF>
The following example configures the module to only use GPS satellites.
$PMTK353,1,0,0,0,0*2A<CR><LF>
The following example configures the module to use GPS and GLONASS
satellites.
$PMTK353,1,1,0,0,0*2B<CR><LF>
GNSS Search System Command and Response
Write Message
Start Msg ID GPS GLNS GAL GALF BEI Checksum End
$PMTK 353 ,GPS ,GLNS ,GAL ,GALF ,BEI *Cksum <CR><LF>
Acknowledge Response Message
Start Msg ID CMD Flag GPS GLNS GAL GALF BEI Checksum End
$PMTK 001 ,353 ,Flg ,GPS ,GLNS ,GAL ,GALF ,BEI *Cksum <CR><LF>
Figure 45: GNSS Search System Command and Response
Note: The Galileo and Beidou fields are added to modules with date
code 1605 and later.
– – – –
38 39
Static Navigation Threshold
This configures the speed threshold to trigger static navigation. If the
measured speed is below the threshold then the module holds the current
position and sets the speed to zero.
Thold = speed threshold, from 0 to 2.0m/s. 0 = disabled.
The following example sets the threshold to 1.2m/s.
$PMTK386,1.2*3E<CR><LF>
The following example reads the static navigation threshold and the module
responds with 1.2m/s
$PMTK447*35<CR><LF>
$PMTK527,1.20*03<CR><LF>
The static navigation threshold configuration returns to the default values
after a reset or restart.
Static Navigation Threshold Command and Response
Write Message
Start Msg ID Thold Checksum End
$PMTK 386 ,Thold *Cksum <CR><LF>
Acknowledge Response Message
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,386 ,Flg *Cksum <CR><LF>
Read Message
Start Msg ID Checksum End
$PMTK 447 *35 <CR><LF>
Response Message
Start Msg ID Thold Checksum End
$PMTK 527 ,Thold *Cksum <CR><LF>
Figure 46: Static Navigation Threshold Command and Response
Enable Ephemeris Prediction
This enables or disables the module’s built-in ephemeris prediction.
This message is formatted slightly differently from the other messages. The
same Message ID is used for the read, write and response and the first
payload field (CMD) indicates which type of message it is. A 0 is a read, a 1
is a write and a 2 is a response to a read.
Enable = enable ephemeris prediction
0 = disabled
1 = enabled
The following example enables prediction.
$PMTK869,1,1*35<CR><LF>
The following example reads the configuration.
$PMTK869,0*29<CR><LF>
The module responds with the first example if prediction is disabled and the
second if it is enabled.
$PMTK869,2,0*37<CR><LF>
$PMTK869,2,1*36<CR><LF>
Enable Ephemeris Prediction Command and Response
Write Message
Start Msg ID CMD Enable Checksum End
$PMTK 869 ,1 ,Enable *Cksum <CR><LF>
Acknowledge Response Message
Start Msg ID CMD Flag Checksum End
$PMTK 001 ,869 ,Flg *Cksum <CR><LF>
Read Message
Start Msg ID CMD Enable Checksum End
$PMTK 869 ,0 ,Enable *Cksum <CR><LF>
Response Message
Start Msg ID CMD Enable Checksum End
$PMTK 869 ,2 ,Enable *Cksum <CR><LF>
Figure 47: Enable Ephemeris Prediction Command and Response
vcc 20 19 18 12 H o Z
– – – –
40 41
Typical Applications
Figure 48 shows the GM Series GNSS receiver in a typical application using
a passive antenna.
A microcontroller UART is connected to the receiver’s UART for passing
data and commands. A 3.3V coin cell battery is connected to the
VBACKUP line to provide power to the module’s memory when main
power is turned off.
Figure 49 shows the module using an active antenna.
A 300Ω ferrite bead is used to put power from VOUT onto the antenna line
to power the active antenna.
NC
1
NC
2
1PPS
3
TX
4
RX
5
GND
21
NC
6
LCKIND
7
8
NC
9
NC
10
GND 20
RFIN 19
GND 18
VOUT 17
NC 16
GND 22
NC 15
NC 14
NC 13
VCC 12
VBACKUP 11
µP
TX
RX
GND
VCC
GND
GND
VCC
GND
VCC
GND
300
Ferrite Bead
RESET
NC
1
NC
2
1PPS
3
TX
4
RX
5
GND
21
NC
6
LCKIND
7
8
NC
9
NC
10
GND 20
RFIN 19
GND 18
VOUT 17
NC 16
GND 22
NC 15
NC 14
NC 13
VCC 12
VBACKUP 11
µP
TX
RX
GND
VCC
GND
GND
VCC
GND
VCC
GND
RESET
Figure 48: Circuit Using the GM Series Module with a Passive Antenna
Figure 49: Circuit Using the GM Series Module with a an Active Antenna
Trace
Board
Ground plane
Example Microstrip Calculations
Dielectric Constant Width/Height
Ratio (W/d)
Effective Dielectric
Constant
Characteristic
Impedance (Ω)
4.80 1.8 3.59 50.0
4.00 2.0 3.07 51.0
2.55 3.0 2.12 48.0
Figure 50: Microstrip Formulas
Figure 51: Example Microstrip Calculations
Microstrip Details
A transmission line is a medium whereby RF energy is transferred from
one place to another with minimal loss. This is a critical factor, especially in
high-frequency products like Linx RF modules, because the trace leading
to the module’s antenna can effectively contribute to the length of the
antenna, changing its resonant bandwidth. In order to minimize loss and
detuning, some form of transmission line between the antenna and the
module should be used unless the antenna can be placed very close (<18in)
to the module. One common form of transmission line is a coax cable and
another is the microstrip. This term refers to a PCB trace running over a
ground plane that is designed to serve as a transmission line between the
module and the antenna. The width is based on the desired characteristic
impedance of the line, the thickness of the PCB and the dielectric constant
of the board material. For standard 0.062in thick FR-4 board material, the
trace width would be 111 mils. The correct trace width can be calculated
for other widths and materials using the information in Figure 50 and
examples are provided in Figure 51. Software for calculating microstrip lines
is also available on the Linx website.
F _H_ a D D B La? D D D D D
– – – –
42 43
Board Layout Guidelines
The module’s design makes integration straightforward; however, it
is still critical to exercise care in PCB layout. Failure to observe good
layout techniques can result in a significant degradation of the module’s
performance. A primary layout goal is to maintain a characteristic
50-ohm impedance throughout the path from the antenna to the module.
Grounding, filtering, decoupling, routing and PCB stack-up are also
important considerations for any RF design. The following section provides
some basic design guidelines which may be helpful.
During prototyping, the module should be soldered to a properly laid-out
circuit board. The use of prototyping or “perf” boards will result in poor
performance and is strongly discouraged.
The module should, as much as reasonably possible, be isolated from
other components on your PCB, especially high-frequency circuitry such as
crystal oscillators, switching power supplies, and high-speed bus lines.
When possible, separate RF and digital circuits into different PCB regions.
Make sure internal wiring is routed away from the module and antenna, and
is secured to prevent displacement.
Do not route PCB traces directly under the module. There should not be
any copper or traces under the module on the same layer as the module,
just bare PCB. The underside of the module has traces and vias that could
short or couple to traces on the product’s circuit board.
The Pad Layout section shows a typical PCB footprint for the module. A
ground plane (as large and uninterrupted as possible) should be placed on
a lower layer of your PC board opposite the module. This plane is essential
for creating a low impedance return for ground and consistent stripline
performance.
Use care in routing the RF trace between the module and the antenna
or connector. Keep the trace as short as possible. Do not pass under
the module or any other component. Do not route the antenna trace on
multiple PCB layers as vias will add inductance. Vias are acceptable for
tying together ground layers and component grounds and should be used
in multiples.
Each of the module’s ground pins should have short traces tying
immediately to the ground plane through a via.
Bypass caps should be low ESR ceramic types and located directly
adjacent to the pin they are serving.
A 50-ohm coax should be used for connection to an external antenna.
A 50-ohm transmission line, such as a microstrip, stripline or coplanar
waveguide should be used for routing RF on the PCB. The Microstrip
Details section provides additional information.
In some instances, a designer may wish to encapsulate or “pot” the
product. There is a wide variety of potting compounds with varying
dielectric properties. Since such compounds can considerably impact
RF performance and the ability to rework or service the product, it is
the responsibility of the designer to evaluate and qualify the impact and
suitability of such materials.
Pad Layout
The pad layout diagram in Figure 52 is designed to facilitate both hand and
automated assembly.
0.028
(0.70)
0.036
(0.92)
0.512
(13.00)
0.050
(1.27) 0.050
(1.27)
0.036
(0.92)
0.020
(0.50)
0.045
(1.15)
Figure 52: Recommended PCB Layout
Feflx mum—s c
– – – –
44 45
Production Guidelines
The module is housed in a hybrid SMD package that supports hand and
automated assembly techniques. Since the modules contain discrete
components internally, the assembly procedures are critical to ensuring
the reliable function of the modules. The following procedures should be
reviewed with and practiced by all assembly personnel.
Hand Assembly
Pads located on the bottom
of the module are the primary
mounting surface (Figure 53).
Since these pads are inaccessible
during mounting, castellations
that run up the side of the module
have been provided to facilitate
solder wicking to the module’s
underside. This allows for very
quick hand soldering for prototyping and small volume production. If the
recommended pad guidelines have been followed, the pads will protrude
slightly past the edge of the module. Use a fine soldering tip to heat the
board pad and the castellation, then introduce solder to the pad at the
module’s edge. The solder will wick underneath the module, providing
reliable attachment. Tack one module corner first and then work around the
device, taking care not to exceed the times in Figure 54.
Automated Assembly
For high-volume assembly, the modules are generally auto-placed.
The modules have been designed to maintain compatibility with reflow
processing techniques; however, due to their hybrid nature, certain aspects
of the assembly process are far more critical than for other component
types. Following are brief discussions of the three primary areas where
caution must be observed.
Castellations
PCB Pads
Soldering Iron
Tip
Solder
Figure 53: Soldering Technique
Warning: Pay attention to the absolute maximum solder times.
Figure 54: Absolute Maximum Solder Times
Absolute Maximum Solder Times
Hand Solder Temperature: +427ºC for 10 seconds for lead-free alloys
Reflow Oven: +240°C max (see Figure 55)
Reflow Temperature Profile
The single most critical stage in the automated assembly process is the
reflow stage. The reflow profile in Figure 55 should not be exceeded
because excessive temperatures or transport times during reflow will
irreparably damage the modules. Assembly personnel need to pay careful
attention to the oven’s profile to ensure that it meets the requirements
necessary to successfully reflow all components while still remaining
within the limits mandated by the modules. The figure below shows the
recommended reflow oven profile for the modules.
Shock During Reflow Transport
Since some internal module components may reflow along with the
components placed on the board being assembled, it is imperative that
the modules not be subjected to shock or vibration during the time solder
is liquid. Should a shock be applied, some internal components could be
lifted from their pads, causing the module to not function properly.
Washability
The modules are wash-resistant, but are not hermetically sealed. Linx
recommends wash-free manufacturing; however, the modules can be
subjected to a wash cycle provided that a drying time is allowed prior
to applying electrical power to the modules. The drying time should be
sufficient to allow any moisture that may have migrated into the module
to evaporate, thus eliminating the potential for shorting damage during
power-up or testing. If the wash contains contaminants, the performance
may be adversely affected, even after drying.
Preheat:
150 - 200°C
Peak: 240+0/-5°C
25 - 35sec
220°C
2 - 4°C/sec
120 - 150sec
2 - 3°C/sec
60 - 80sec
30°C
Figure 55: Maximum Reflow Temperature Profile
– – – –
46 47
Master Development System
The GM Series Master Development System provides all of the tools
necessary to evaluate the GM Series GNSS receiver module. The system
includes a fully assembled development board, an active antenna,
development software and full documentation.
The development board includes a power supply, a prototyping area for
custom circuit development, and an OLED display that shows the GPS
data without the need for a computer. A USB interface is also included
for use with a PC running custom software or the included development
software.
The Master Development System software enables configuration of the
receiver and displays the satellite data output by the receiver. The software
can select from among all of the supported NMEA protocols for display of
the data.
Full documentation for the board and software is included in the
development system, making integration of the module straightforward.
Figure 56: The GM Series Master Development System
Figure 57: The Master Development System Software
GM Series GNSS Receiver Supported Datums
Number Datum Region
0 WGS1984 International
1 Tokyo Japan
2 Tokyo Mean for Japan, South Korea,
Okinawa
3 User Setting User Setting
4 Adindan Burkina Faso
5 Adindan Cameroon
6 Adindan Ethiopia
7 Adindan Mali
8 Adindan Mean for Ethiopia, Sudan
9 Adindan Senegal
10 Adindan Sudan
11 Afgooye Somalia
12 Ain El Abd1970 Bahrain
13 Ain El Abd1970 Saudi Arabia
14 American Samoa1962 American Samoa Islands
15 Anna 1 Astro1965 Cocos Island
16 Antigua Island Astro1943 Antigua(Leeward Islands)
17 Arc1950 Botswana
18 Arc1950 Burundi
19 Arc1950 Lesotho
20 Arc1950 Malawi
21 Arc1950 Mean for Botswana, Lesotho, Malawi,
Swaziland, Zaire, Zambia, Zimbabwe
22 Arc1950 Swaziland
23 Arc1950 Zaire
24 Arc1950 Zambia
25 Arc1950 Zimbabwe
26 Arc1960 Mean For Kenya Tanzania
27 Arc1960 Kenya
28 Arc1960 Tanzania
29 Ascension Island1958 Ascension Island
30 Astro Beacon E 1945 Iwo Jima
31 Astro Dos 71/4 St Helena Island
Appendix A
The following datums are supported by the GM Series.
– – – –
48 49
GM Series GNSS Receiver Supported Datums
Number Datum Region
32 Astro Tern Island (FRIG) 1961 Tern Island
33 Astronomical Station 1952 Marcus Island
34 Australian Geodetic 1966 Australia, Tasmania
35 Australian Geodetic 1984 Australia, Tasmania
36 Ayabelle Lighthouse Djibouti
37 Bellevue (IGN) Efate and Erromango Islands
38 Bermuda 1957 Bermuda
39 Bissau Guuinea-Bissau
40 Bogota Observatory Colombia
41 Bukit Rimpah Indonesia (Bangka and Belitung Ids)
42 Camp Area Astro Antarctica (McMurdi Camp Area)
43 Campo Inchauspe Argentina
44 Canton Astro1966 Phoenix Island
45 Cape South Africa
46 Cape Canaveral Bahamas, Florida
47 Carthage Tunisia
48 Chatham Island Astro1971 New Zealand (Chatham Island)
49 Chua Astro Paraguay
50 Corrego Alegre Brazil
51 Dabola Guinea
52 Deception Island Deception Island, Antarctica
53 Djakarta (Batavia) Indonesia (Sumatra)
54 Dos 1968 New Georgia Islands (Gizo Island)
55 Easter Island 1967 Easter Island
56 Estonia Coordinate System1937 Estonia
57 European 1950 Cyprus
58 European 1950 Egypt
59 European 1950 England, Channel Islands, Scotland,
Shetland Islands
60 European 1950 England, Ireland, Scotland, Shetland
Islands
61 European 1950 Finland, Norway
62 European 1950 Greece
63 European 1950 Iran
64 European 1950 Italy (Sardinia)
65 European 1950 Italy (Sicily)
GM Series GNSS Receiver Supported Datums
Number Datum Region
66 European 1950 Malta
67 European 1950
Mean For Austria, Belgium, Denmark,
Finland, France, W Germany,
Gibraltar, Greece, Italy, Luxembourg,
Netherlands, Norway, Portugal, Spain,
Sweden, Switzerland
68 European 1950 Mean For Austria, Denmark, France,
W Germany, Netherland, Switzerland
69 European 1950 Mean For Iraq, Israel, Jordan,
Lebanon, Kuwait, Saudi Arabia, Syria
70 European 1950 Portugal, Spain
71 European 1950 Tunisia,
72 European 1979
Mean For Austria, Finland
,Netherlands ,Norway, Spain,
Sweden, Switzerland
73 Fort Thomas 1955 Nevis St Kitts (Leeward Islands)
74 Gan 1970 Republic Of Maldives
75 Geodetic Dataum 1970 New Zealand
76 Graciosa Base SW1948 Azores (Faial, Graciosa, Pico, Sao,
Jorge, Terceria)
77 Guam1963 Guam
78 Gunung Segara Indonesia (Kalimantan)
79 Gux l Astro Guadalcanal Island
80 Herat North Afghanistan
81 Hermannskogel Datum Croatia-Serbia, Bosnia-Herzegoivna
82 Hjorsey 1955 Iceland
83 Hongkong 1963 Hong Kong
84 Hu Tzu Shan Taiwan
85 Indian Bangladesh
86 Indian India, Nepal
87 Indian Pakistan
88 Indian 1954 Thailand
89 Indian 1960 Vietnam (Con Son Island)
90 Indian 1960 Vietnam (Near 16 deg N)
91 Indian 1975 Thailand
92 Indonesian 1974 Indonesian
93 Ireland 1965 Ireland
94 ISTS 061 Astro 1968 South Georgia Islands
95 ISTS 073 Astro 1969 Diego Garcia
– – – –
50 51
GM Series GNSS Receiver Supported Datums
Number Datum Region
96 Johnston Island 1961 Johnston Island
97 Kandawala Sri Lanka
98 Kerguelen Island 1949 Kerguelen Island
99 Kertau 1948 West Malaysia and Singapore
100 Kusaie Astro 1951 Caroline Islands
101 Korean Geodetic System South Korea
102 LC5 Astro 1961 Cayman Brac Island
103 Leigon Ghana
104 Liberia 1964 Liberia
105 Luzon Philippines (Excluding Mindanao)
106 Luzon Philippines (Mindanao)
107 M'Poraloko Gabon
108 Mahe 1971 Mahe Island
109 Massawa Ethiopia (Eritrea)
110 Merchich Morocco
111 Midway Astro 1961 Midway Islands
112 Minna Cameroon
113 Minna Nigeria
114 Montserrat Island Astro 1958 Montserrat (Leeward Island)
115 Nahrwan Oman (Masirah Island)
116 Nahrwan Saudi Arabia
117 Nahrwan United Arab Emirates
118 Naparima BWI Trinidad and Tobago
119 North American 1927 Alaska (Excluding Aleutian Ids)
120 North American 1927 Alaska (Aleutian Ids East of 180
degW)
121 North American 1927 Alaska (Aleutian Ids West of 180
degW)
122 North American 1927 Bahamas (Except San Salvador
Islands)
123 North American 1927 Bahamas (San Salvador Islands)
124 North American 1927 Canada (Alberta, British Columbia)
125 North American 1927 Canada (Manitoba, Ontario)
126 North American 1927 Canada (New Brunswick,
Newfoundland, Nova Scotia, Quebec)
127 North American 1927 Canada (Northwest Territories,
Saskatchewan)
GM Series GNSS Receiver Supported Datums
Number Datum Region
128 North American 1927 Canada (Yukon)
129 North American 1927 Canal Zone
130 North American 1927 Cuba
131 North American 1927 Greenland (Hayes Peninsula)
132 North American 1927
Mean For Antigua, Barbados,
Barbuda, Caicos Islands, Cuba,
Dominican, Grand Cayman, Jamaica,
Turks Islands
133 North American 1927
Mean for Belize, Costa Rica, El
Salvador, Guatemala, Honduras,
Nicaragua
134 North American 1927 Mean for Canada
135 North American 1927 Mean for Conus
136 North American 1927
Mean for Conus (East of Mississippi,
River Including Louisiana, Missouri,
Minnesota)
137 North American 1927
Mean for Conus (West of Mississippi,
River Excluding Louisiana, Minnesota,
Missouri)
138 North American 1927 Mexico
139 North American 1983 Alaska (Excluding Aleutian Ids)
140 North American 1983 Aleutian Ids
141 North American 1983 Canada
142 North American 1983 Conus
143 North American 1983 Hawaii
144 North American 1983 Mexico, Central America
145 North Sahara 1959 Algeria
146 Observatorio Meteorologico 1939 Azores (Corvo and Flores Islands)
147 Old Egyptian 1907 Egypt
148 Old Hawaiian Hawaii
149 Old Hawaiian Kauai
150 Old Hawaiian Maui
151 Old Hawaiian Mean for Hawaii, Kauai, Maui, Oahu
152 Old Hawaiian Oahu
153 Oman Oman
154 Ordnance Survey Great Britain 1936 England
155 Ordnance Survey Great Britain 1936 England, Isle of Man, Wales
156 Ordnance Survey Great Britain 1936 Mean For England, Isle of Man,
Scotland, Shetland Island, Wales
– – – –
52 53
GM Series GNSS Receiver Supported Datums
Number Datum Region
157 Ordnance Survey Great Britain 1936 Scotland, Shetland Islands
158 Ordnance Survey Great Britain 1936 Wales
159 Pico de las Nieves Canary Islands
160 Pitcairn Astro 1967 Pitcairn Island
161 Point 58 Mean for Burkina Faso and Niger
162 Pointe Noire 1948 Congo
163 Porto Santo 1936 Porto Santo, Madeira Islands
164 Provisional South American 1956 Bolivia
165 Provisional South American 1956 Chile (Northern Near 19 deg S)
166 Provisional South American 1956 Chile (Southern Near 43 deg S)
167 Provisional South American 1956 Colombia
168 Provisional South American 1956 Ecuador
169 Provisional South American 1956 Guyana
170 Provisional South American 1956 Mean for Bolivia Chile, Colombia,
Ecuador, Guyana, Peru, Venezuela
171 Provisional South American 1956 Peru
172 Provisional South American 1956 Venezuela
173 Provisional South Chilean 1963 Chile (Near 53 deg S) (Hito XVIII)
174 Puerto Rico Puerto Rico, Virgin Islands
175 Pulkovo 1942 Russia
176 Qatar National Qatar
177 Qornoq Greenland (South)
178 Reunion Mascarene Island
179 Rome 1940 Italy (Sardinia)
180 S-42 (Pulkovo 1942) Hungary
181 S-42 (Pulkovo 1942) Poland
182 S-42 (Pulkovo 1942) Czechoslavakia
183 S-42 (Pulkovo 1942) Lativa
184 S-42 (Pulkovo 1942) Kazakhstan
185 S-42 (Pulkovo 1942) Albania
186 S-42 (Pulkovo 1942) Romania
187 S-JTSK Czechoslavakia (Prior 1 Jan1993)
188 Santo (Dos) 1965 Espirito Santo Island
189 Sao Braz Azores (Sao Miguel, Santa Maria Ids)
190 Sapper Hill 1943 East Falkland Island
191 Schwarzeck Namibia
GM Series GNSS Receiver Supported Datums
Number Datum Region
192 Selvagem Grande 1938 Salvage Islands
193 Sierra Leone 1960 Sierra Leone
194 South American 1969 Argentina
195 South American 1969 Bolivia
196 South American 1969 Brazil
197 South American 1969 Chile
198 South American 1969 Colombia
199 South American 1969 Ecuador
200 South American 1969 Ecuador (Baltra, Galapagos)
201 South American 1969 Guyana
202 South American 1969
Mean For Argentina, Bolivia, Brazil,
Chile, Colombia, Ecuador, Guyana,
Paraguay, Peru, Trinidad and Tobago,
Venezuela
203 South American 1969 Paraguay
204 South American 1969 Peru
205 South American 1969 Trinidad and Tobago
206 South American 1969 Venezuela
207 South Asia Singapore
208 Tananarive Observatory 1925 Madagascar
209 Timbalai 1948 Brunei, E Malaysia (Sabah Sarawak)
210 Tokyo Japan
211 Tokyo Mean for Japan, South Korea,
Okinawa
212 Tokyo Okinawa
213 Tokyo South Korea
214 Tristan Astro 1968 Tristam Da Cunha
215 Viti Levu 1916 Fiji (Viti Levu Island)
216 Voirol 1960 Algeria
217 Wake Island Astro 1952 Wake Atoll
218 Wake-Eniwetok 1960 Marshall Islands
219 WGS 1972 Global Definition
220 WGS 1984 Global Definition
221 Yacare Uruguay
222 Zanderij Suriname
Figure 58: Supported Datums
– – – –
54 55
Notes
Lir'ix TECHNOLOGIES
Disclaimer
Linx Technologies is continually striving to improve the quality and function of its products. For this reason, we
reserve the right to make changes to our products without notice. The information contained in this Data Guide
is believed to be accurate as of the time of publication. Specifications are based on representative lot samples.
Values may vary from lot-to-lot and are not guaranteed. “Typical” parameters can and do vary over lots and
application. Linx Technologies makes no guarantee, warranty, or representation regarding the suitability of any
product for use in any specific application. It is the customer’s responsibility to verify the suitability of the part for
the intended application. NO LINX PRODUCT IS INTENDED FOR USE IN ANY APPLICATION WHERE THE SAFETY
OF LIFE OR PROPERTY IS AT RISK.
Linx Technologies DISCLAIMS ALL WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE. IN NO EVENT SHALL LINX TECHNOLOGIES BE LIABLE FOR ANY OF CUSTOMER’S INCIDENTAL OR
CONSEQUENTIAL DAMAGES ARISING IN ANY WAY FROM ANY DEFECTIVE OR NON-CONFORMING PRODUCTS
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©2017 Linx Technologies. All rights reserved.
The stylized Linx logo, Wireless Made Simple, WiSE, CipherLinx and the stylized CL logo are trademarks of Linx Technologies.
Linx Technologies
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www.linxtechnologies.com

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