GPS- User Manual

Quik Starter Guide

Step1 Open the package, which contains the following items (Refer Fig. I).

Top tray contains:GPS User’s Guide

Bottom tray contains: GPS Active antenna with SMB connector at one endRS 232 cable with 9 pin D-type connectorsCigarette lighter cable

Step 2 Apart from the above, the user will also need the following to set up the receiver:IBM compatible Notebook PCPower supply 12 V DC, 2 A

Step 3 Connect the GPS Receiver to the Notebook PC through the RS 232 cable.

Step 4 Fix the antenna (supplied) on a metallic surface which is horizontal and smooth. If you are placing the antenna on the top of your car, you may use a small piece of paper underneath the antenna. This will prevent any possible scratches on your car due to the magnetic antenna mount. The location of the antenna should be so chosen that it has a clear view of the sky.

Step 5 Connect the antenna cable with the SMB connector to GPS Receiver front panel. Route the cable in such a way that it does not get jammed through the doors or window panes. Ensure the SMB connector is properly connected at the receiver end.

Step 6 Power the GPS receiver from the 3.3V ( + 0.3 ) DC Power Supply using power sorce.

Step 7 Power and boot your Notebook PC.

Step 8 Ensure that the receiver is connected to the COM port of the Notebook PC or you will have to configure the com port as described in Step 9.

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Step 9 Now make the following settings: Select COM port to which the GPS receiver is connected.Baud rate 9600, Stop bits 2,Data bits 8,Parity None

Status bar indicates Connected if Power supply and RS232 connections are correct.

For the Status Bar to show Connected, at least one message should be enabled.

Only NMEA mode supported

Step 11 Position Trace can be done using the front end software.

Product Highlights of GPS Receiver

12 Correlator channels Cold start TTFF of 42s Warm start TTFF of 30s Very fast Hot Start TTFF of 4 sec Very good Reacquisition sensitivity Very good Tracking sensitivity Very fast reacquisition of signals Excellent Urban Canyon performance Raw measurement data output Standard interfaces viz., RS 232

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Features of this Revision

Industry leading sensitivity figures among standalone GPS receivers Excellent Foliage and Urban Canyon tracking performance with repeatable

retrace Multipath mitigation algorithms in software Very fast Hot start Custom messages to test Time to first fix (TTFF)

AcronymsDSP Digital Signal Processor

AGC Automatic Gain Control

BITE Built in Test

C/A Coarse/Acquisition

DOP Dilution of Precision

DSP Digital Signal Processor

ECEF Earth Centered Earth Fixed

EMC Electro Magnetic Compatibility

ESD Electro Static Discharge

GDOP Geometric Dilution of Precision

GMT Greenwich Mean Time

GPS Global Positioning System

GPSR Global Positioning System Receiver

HDOP Horizontal Dilution of Precision

IF Intermediate Frequency

IVHS Intelligent Vehicle Highway System

LED Light Emitting Diode

LNA Low Noise Amplifier

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OEM Original Equipment Manufacturer

PDOP Position Dilution of Precision

PLL Phase Locked Loop

PRN Pseudo Random Number

PTTI Precise Time and Timing Interval

RF Radio Frequency

RTC Real Time Clock

SA Selective Availability

SAW Surface Acoustic Wave

SNR Signal to Noise Ratio

SPS Standard Positioning Service

SV Satellite Vehicle

TDOP Time Dilution of Precision

UERE User Equivalent Range Error

URA User Range Accuracy

URE User Range Error

VCO Voltage Controlled Oscillator

VDOP Vertical Dilution of Precision

VLSI Very Large Scale Integration

WGS 84 World Geodetic System (1984)

GlossaryAlmanac This is a part of the navigation message transmitted by each

satellite, which includes orbit information of all satellites, clock correction and atmospheric delay parameters. GPS receivers need almanac to compute the visibility information about the satellites.

Azimuth The angular distance between the true North and the object in consideration in the horizontal plane.

C/A Code

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This is Coarse/Acquisition code, which is a pseudo random noise sequence modulated on the GPS L1 signal and transmitted by all the GPS satellites for ranging. C/A code is a Gold code of 1 millisecond in length and is transmitted at a chipping rate of 1.023 MHz.

Chip The length of time required to transmit either a 1 or 0 in a pseudo random code.

Chip rate Number of chips per second.

Control Segment The ground based segment of the GPS, consisting of Monitor stations, a Master Control Station and Ground antennas.

Dilution of Precision (DOP)

DOP is a measure of the contribution of the relative geometry of the user and the GPS satellites to the error in the position fix.

Elevation Angle made by the line joining the user and the satellite with the horizontal plane.

Ephemeris Part of the Navigation data transmitted from each satellite containing precise orbit information and clock corrections for that satellite. Ephemeris is used by the receiver to compute the precise position coordinates of the satellites used for ranging.

Geometric Dilution of

Precision (GDOP)

GDOP describes the DOP in position as well as the time computed using the GPS satellites.

GDOP2 = PDOP2 + TDOP2

GPS The Global Positioning System (GPS) is a space based radio positioning, navigation and time transfer system which operates at all times of the day, under all weather conditions and any where on or near the surface of the Earth.

GPS L1 signal Transmitted by all GPS satellites at a carrier frequency of 1575.42 MHz. This signal is modulated by the C/A code and navigation data.

Horizontal Dilution of

Precision (HDOP)

Contribution of the relative geometry of the satellite constellation and the user’s position, DOP, to the error in the horizontal dimension of the position.

Monitor station Group of stations located around the world as a part of the GPS Control Segment to monitor satellite clock and orbital

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parameters.

Navigation Data Data modulated on the C/A code, which contains ephemeris, almanac and other information. The data is transmitted at 50 bits/sec.

NAVSTAR The name given to the group of satellites, which are built by Rockwell International.

Position Dilution of Precision

(PDOP)

PDOP is the DOP in the position fix. PDOP includes the contribution in all the three dimensions of the position fix.

PDOP2 = HDOP2 + VDOP2

Pseudo range Measure of apparent transit time from the satellite to the receiver antenna expressed as distance. The pseudo range is obtained by multiplying the apparent transit time by the speed of light. Pseudorange differs from true range due to the fact that the clocks in the receiver and the satellites are not synchronized.

RTCM Radio Technical Commission for Maritime Services set up to define data link standards for Differential GPS.

Selective Availability (SA)

An U.S. Department of Defense program to control the accuracy of pseudo range measurements, whereby the user gets erroneous pseudo range measurements by certain controlled amount.

Space Segment GPS Space Segment consisting of 28 satellites in six orbital planes.

Standard Positioning

Service (SPS)

This is a civil positioning and timing service which will be available to all GPS users on a worldwide basis at an accuracy level set by the United States Department of Defense.

SV Satellite Vehicle or Space Vehicle.

Time Dilution of Precision (TDOP)

Contribution of the relative geometry of the satellite constellation and the user’s position, DOP, to the error in the time fix.

User Equivalent Range Error

(UERE)

The component of the system accuracy which is independent of location and time, that represents the receiver ranging error based on the satellites in view.

User Range A statistical indicator of the ranging accuracy’s achieved with a

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Accuracy (URA) specific satellite based on historical data.

User Range Error (URE)

The error component along the line of sight between the user and the satellite being used for measurement.

User Segment The GPS Segment consisting of the receivers.

Vertical Dilution of Precision

(VDOP)

Contribution of the relative geometry of the satellite constellation and the user’s position, DOP, to the error in the vertical dimension of the position fix.

WGS 84 World Geodetic System (1984), the mathematical ellipsoid used by GPS since January 1984.

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GPS Principles

OverviewThe Global Positioning System (GPS) is a space based radio positioning, navigation and time transfer system which operates at all times of the day, under all weather conditions and everywhere on or near Earth. GPS consists of three segments viz., Space, Control and User. The Space Segment is the set of 24 satellites (plus 3 spare satellites) orbiting the earth once in 12 hours in six orbital planes with four satellites in each orbital plane. Control Segment based at four locations on the earth monitors and controls the satellites. User Segment is the Global Positioning System Receivers (GPSR) used by a large number of users all over the world. GPSR provides accurate and absolute position, velocity and time.

GPS Receiver finds diverse range of uses such as:Intelligent Vehicle Highway System (IVHS)Personal navigation by Land, Sea and AirFleet Management Land and construction SurveyingMapping to create highly precise mapsAnimal trackingSynchronization of timeVehicle security systemsCommunication sets with GPS for PoliceIntegrated navigation solutions

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Chapter 1 – GPS Principles

The decisive advantages of GPS over other navigation systems are:

24 hour worldwide coverageAll weather conditionsAccurate 3 dimensional position and time informationResistance to jammingEasy integration/adaptability with other systemsCan be used on Land, Sea or Air

Theory of Operation of GPS The GPS system consists of three segments (Refer Fig. 1.1) viz.,Space SegmentControl SegmentUser Segment

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SpaceSegment

Space Segment consists of a set of 24 satellites (plus 3 spare satellites) orbiting with the period of 12 hours sidereal time. The satellites are placed at an altitude of approximately 10,898 nautical miles above the surface of the earth and these satellites are arranged in six orbital planes inclined at 55° with four satellites in each orbit. Each satellite continually transmits the following signals:L1 signal at 1575.42 MHzL2 signal at 1227.60 MHz

The above frequencies are phase modulated by two ranging signals viz., P-code for military users and C/A code for civilian users. In addition, navigation messages are modulated and transmitted along with the ranging signals. Satellites use precise atomic clocks for synchronization with GPS time.

Control Segment

Control Segment consists of a master control station, four monitor stations located strategically around the earth to maximize satellite coverage and ground antennas. The monitor stations receive satellite data and communicate to the master control station. The master control station updates navigation messages to all satellites through the ground antennas.

User Segment User Segment consists of a large number of GPS receivers (GPSRs) used all over the world. The GPS receiver, which is of current interest, receives and processes satellite signals to compute user’s position, velocity and time.

The principle of computation of the user’s position using the GPS satellite signals in a receiver can be described briefly as follows. The GPS constellation of satellites is so designed that sufficient number of satellites are visible at any point on the surface of the earth at all times. Each of the GPS satellites transmits a unique pseudo-random code continuously. GPS receiver uses correlation techniques to acquire satellite signals, extract navigation messages and perform ranging measurements. GPS receiver measures transit time of the signal and hence range from satellites to the receiver.

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Range measurements from at least four satellites are needed to locate precisely the user’s position in the three dimensional space. Ranging measurements from three satellites are necessary to compute user’s position in 2 dimensions.

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Fig 1.1 Three Segments of GPS

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Functional Components of a GPS ReceiverA typical GPS receiver used in civilian applications would have the functional components shown in Fig 1.2

Fig 1.2 Functional components of a GPS Receiver

Antenna The Antenna operates at 1575.42 MHz to receive the GPS L1 signals from all the visible satellites.

RF Down Converter

The RF Down Converter amplifies, filters and down-converts the L1 signal to give a low IF digital signal suitable for processing by the Correlator.

Correlator The Correlator acquires the satellite signals, extracts the data bits and performs range and doppler measurements.

Navigation Processor

The Navigation Processor extracts the navigation messages, computes the user’s position, velocity and time from the measurements generated by the Correlator.

User Interface This may typically include a keyboard and a display to enable the user to program and monitor the outputs from the GPS receiver.

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Functional Description of the GPS Receiver

Overview GPS is a Global Positioning System Receiver chipset solution (Refer Fig. 2.1) designed around a programmable platform - ADSST2188 processor. ADSST2188 is a 16 bit fixed point DSP with on-chip SRAM and integrated I/O peripheral support.

Fig 2.1 GPS -HS receiver block diagram

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Chapter 2 Functional Description of GPS Receiver

GPS is designed to simultaneously acquire and track 12 GPS satellite signals and compute user’s accurate position, velocity and time. GVision software provides a Graphical User Interface for the GPS -HS based GPS receiver on an IBM-PC, which can be connected to the GPS receiver through an RS 232 link.

Functional DescriptionThe GPS receiver consists of (Refer Fig. 2.2):RF Front End with Antenna Correlator Navigation ModuleUser Interface

Fig 2.2 Four Sections of the GPS Receiver

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The L1 GPS signal, received through an active antenna, gets down-converted to a low IF in the RF front end - designed around a VLSI down converter. This IF signal is sampled at a predefined rate and then quantized in an A/D converter inside the RF front end. The quantized samples of the IF signal are received serially by the Digital Signal Processor (DSP) and stored in an internal buffer. The down conversion of this stored IF signal to base band, correlation of the signal with the local code, carrier & code tracking loops and computation of user’s position, velocity and time as well as the communication interface to a host are all implemented in software running on the DSP.

Antenna Section

Antenna Section consists of:

An antenna operating at 1575.42 MHz (L1 signal)A built-in low noise amplifier (LNA)

The antenna receives L1 signal from all visible satellites with almost equal gain through its hemispherical radiation pattern (Refer Fig. 3.3). The satellite signal at the antenna is very weak (-130 dBm) with an SNR (Signal to Noise Ratio) of less than -16 dB. The built in low noise amplifier compensates for the loss of signal in the RF cable.

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Fig 3.3 Radiation Patterns - GPS Antenna

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The main functions of the GPS antenna are:Reception of the GPS L1 signal at 1575.42 MHzAmplification of the received satellite signals

RF Front End RF Front End is designed around a commercially available VLSI RF down converter with a set of RF passive components. It receives the input signal from the antenna section and provides down converted digitized IF signal to the Correlator. RF front end consists of the following major components:Band Pass Filter VLSI Down ConverterLC filter SAW filter Reference clock

The L1 GPS satellite signal is first passed through a band pass filter and then down converted to a low IF in the VLSI down converter.

The down conversion of L1 frequency is performed in three mixer stages to generate IF frequencies. The local oscillator frequencies required for mixing operations are generated in a frequency synthesizer that gets input from the reference clock. A band pass filter and an amplifier follow each stage of the mixer.

The final output from the RF front end is a digitized low IF signal which is processed in the next section - Correlator.

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The main functions of the RF Front End are:Reception of L-band GPS signal from the antennaRF signal filteringDown conversion of RF signal to a low IFDigitization of the low IF output signal

Correlator Correlator receives digitized low IF output from the RF Front End and performs measurements on the satellite signal. The measurement outputs are sent to the navigation module, which computes the user’s position, velocity and time.

The Correlator consists of:Buffers to store sampled low IF signalCarrier generatorCode generator

The main functions of the Correlator are:Reception and storage of digitized low IF signal in buffersDown-conversion of low IF signal to basebandParallel processing of 12 channelsGeneration of the local carrier Generation of local C/A codes for 32 satellitesCorrelation of received signal with the local codeInterface to Navigation Module

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Navigation Module

Navigation Module receives measurements performed on the satellite signal by the Correlator. The pseudo range and delta range measurements for the satellites being tracked by the Correlator are used by the Navigation Module to estimate the user’s position and other parameters.

The Navigation module consists of the following modules:Satellite database managementSatellite selection Channel managementPosition, Velocity and Time solutionInterface to Correlator and User interfaceReal time multitasking executive Measurement data processorInterface to Real Time Clock and Non volatile memoryPrecise Time GeneratorDatum supportRS 232 interface

The position computation algorithm is such that when the position is determined with 3 satellites, the VDOP is 1.0.

User Interface User Interface software supplied along with the GPS receiver runs on an IBM-PC connected to the receiver on an RS 232 link.

Using the software, you can Monitor satellites being searched and tracked Display user’s position, velocity and time Log various NMEA messages Alter Elevation Mask settings Factory Reset the receiver Cold start the receiver Configure the receiver to power down mode Alter various port settings

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Hardware Installation of GPS Receiver

OverviewTo monitor and control GPS receiver operation, Front- End java or similar software should be installed on the computer and initialized. The power input either from a car battery or a standalone external power supply can be provided.

Precautions

A-1

Electrostatic Considerations

The GPS boards contain assemblies sensitive to damage by ESD (Electrostatic discharge). Use ESD precautionary measures while handling the board.

Electromagnetic Considerations

The EMC is not ensured since the OEM applications may vary. However, it is necessary to use GPS receiver in a place, which is free from any strong radiation, to avoid degradation of performance. Typically, this receiver may malfunction if placed very close to transmitting stations. Special precautions may be required to shield the receiver in case of strong radiation. The board is enclosed inside a metallic container to reduce any electromagnetic interference.

Thermal Considerations

Operating temperature of the GPS receiver is from 0°C to 70°C for the commercial grade version and -40°C to 85°C for the Industrial grade version. Before installation, it must be ensured that the temperature of the environment is not too high. The air circulation should not be poor.

Grounding Considerations

The receiver is grounded through pin 5 of RS 232 connector and negative terminal of the 12 volts power supply input. The mounting holes of the board are connected to the case.

Packaging After opening the package, check for any damage to the connectors, switches, LEDs, cables. Using any damaged part does not guarantee proper working of the GPS receiver.

Time output The Precise Time from the receiver is output from the receiver via a BNC. The Timing pulse is at TTL level for easy interface to other applications.

Pin No. Signal name Description

1 Time Center pin

2 Ground Outer metallic casing

The time output is buffered to 5V TTL at the BNC.

ANT connector This is a SMB (male) panel mounting type connector for connecting antenna to GPS receiver with the antenna cable.

Pin No. Signal name Description

1 RF signal Center pin

2 Ground Outer case

Fig 4.3 GPS receiver board layout

Interface Connector

The interconnection between the GPS -HS GPS receiver board and the motherboard is accomplished via a 20-pin connector. The connector details and description are given below.

Antenna cable The antenna comes with a built in cable with SMB end. This cable connects the antenna to the receiver. The length of the cable is 3m, which is considered adequate for usage in a car.

RS 232 cable This is a 2m long cable with 9-pin D type connectors. This cable connects the GPS receiver to the PC.

Mechanical Details

GPS Receiver The mounting of components inside the GPS receiver along with the dimensions is shown in Fig 4.5. The box contains GPS GPS receiver board and motherboard fixed at four places. The mountings on front panel include ANT connector, PWR indicator, Power connector, PTTI connector, Switch and D type RS 232 connector. The top cover is enclosed on the

housing with four screws as shown in the Fig 4.5.

Fig 4.5 Mounting of components - GPS

Antenna The antenna enclosed in the evaluation kit is from EMTAC (part no. GPA-18A). The antenna is an active antenna with in-built cable. It has a magnetic mount, which is useful when testing in vehicles

GPS -HS Board Dimensions

All dimensions are in mm. All mounting holes are of diameter 2mm.

Fig 4.6 - GPS Board Dimensions

Appendix - A

Standard NMEA Message Formats

NMEA 0183 interface protocol defines the communication interface and the data format for the navigation equipment. This chapter provides an overview of the NMEA messages supported in GPS receiver.

General InformationThe NMEA message structure is defined below.

$MSGID,dl,d2,d3,..................dn*CS[CR]{LF}

MSGID : 5 character mnemonic identifying the message .e.g., GPGGA

dn: data field.

“,” delimiters for the data fields

“*” Check sum delimiter

Check sum calculation Check sum (CS) of all NMEA messages are calculated for all other fields excluding $ * [LF] [CR].

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GPS NMEA MessagesSetting Message Description

Factory Default GGA GPS Fix Data

Factory Default GLL Geographic Position

Factory Default GSA GPS DOP and active satellites

Factory Default GSV GPS Satellites in view

Factory Default RMC Recommended Minimum specific GPS/Transit data

Factory Default VTG Track made good and ground speed

Factory Default ZDA Time and date

UTC time will be transmitted only if almanac is available in the receiver. If almanac is not present in the receiver, GPS time will be transmitted. GPS time is ahead of UTC time by about 13 seconds as on June 2001. Once almanac is collected, UTC time is transmitted. Therefore there can be a jump of 13 seconds in time field of NMEA messages when the receiver switches from no almanac state to almanac available state.

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NMEA message formats

GPZDA messageZDA message contains UTC time, day, month, year and the local time zone.

$GPZDA , hhmmss . s ,dd , mm , yyyy ,aa, bb *CS<CR><LF>

Field Detailshhmmss.s UTC time

hh -> 2 digits of hour.mm -> 2 digits of minutes ss.s -> 2 decimal digits and one fractional digit of second

dd 2 digits of daymm 2 digits of monthyyyy 4 digits of yearaa Zonal Time offset in hours with respect to GMT. If

the time offset is negative a “-” sign is padded before the hours field. This field is not updated.

bb Zonal Time offset in minutes with respect to GMT. Sign is same as that of the hour field. This field is not updated.

* Check sum delimiterCS Check sum

GPGGA messageThe GGA message includes time, position fix and other position related information of GPS receiver.

$GPGGA , hhmmss . s , llll . llll , a , yyyyy . yyyy , b , q , nn , hh .h ,aaaaa . a , M , sss .s , M , aa , aaaa *CS<CR><LF>

Field Detailshhmmss.s UTC time of position fix


llll.llll Latitude in <degree degree minutes minutes . minutes minutes minutes minutes > format

a N for North, S for Southyyyyy.yyyy Longitude in < degree degree degree minutes

minutes minutes minutes minutes minutes > formatb E for East, W for westq Quality indicator 0 -> No GPS, 1-> GPS, 2-

>DGPSnn Number of satellites in usehh.h HDOPaaaaa.a Altitude in meters, If altitude is negative “-“ is

padded before aaaaa.aM Units of altitude M -> meters.sss.s Geoidal separation in meters. If negative, “-“ is

padded before sss.sM Units of geoidal separation in metersAa Age of DGPS data. Field valid only when the

quality indicator is 2 (DGPS)

aaaa Station ID: 0-9999. Valid only in DGPS fix mode.* Check sum delimiterCS Check sum

GPGLL messageThis message includes latitude, longitude, time of position fix and the status information

$GPGLL , llll . llll , a , yyyyy . yyyy , b , hhmmss . s , c *CS<CR><LF>

Field Detailsllll.llll Latitude in <degree degree minutes minutes.

minutes minutes minutes minutes> formata N for North, S for Southyyyyy.yyyy longitude in < degree degree degree minutes

minutes . minutes minutes minutes minutes > format

b E for East, W for westhhmmss.s UTC time of position fix.


c A -> position is available. V -> position is not available

* Check sum delimiterCS Check sum

GPRMC messageThis message includes time, date, position and speed information from the GPS receiver

$GPRMC , hhmmss . s , A , llll . llll , a , yyyyy . yyyy , b , ssss . ss , hhh . hh , ddmmyy , mm . m , d *CS<CR><LF>

Field Detailshhmmss.s UTC time of position fix


A A -> position is available.V ->position is not available.

llll.llll Latitude in <degree degree minutes minutes. Minutes minutes minutes minutes > format

a N for North, S for Southyyyyy.yyyy Longitude in < degree degree degree minutes

minutes . minutes minutes minutes minutes> format

b E for East, W for westssss.ss Speed over ground in Knotshhh.hh Heading in degree with respect to true northddmmyy <day day month month year year>mm.m Magnetic variation in degree This field is not

validd Direction of magnetic variation, This field is not

valid * Check sum delimiterCS Check sum

GPGSA messageThis message indicates the satellite used for navigation, DOP values of the position fix

$GPGSA , a , m , s1 , s2 , s3 , s4 , s5 , s6 , s7 , s8 , s9 , s10 , s11 , sl2 , pp . p , hh . h , vv .v *CS<CR><LF>

Field Detailsa Mode could be manual or automatic

A ->Automatic mode. In this mode the receiver automatically switches between 2D and 3D modedepending on the PDOP and satellite masks.M ->Manual mode. In this mode the receiver is forced to operate in either 2D or 3D mode.

m Mode 1 -> Fix not available, 2 -> 2D position fix, 3-> 3D position fix.

sl....sl2 PRN number of the satellites used for position fix. If less than 12 satellites are used, null in unused fields

pp.p PDOPhh.h HDOPvv.v VDOP* Check sum delimiterCS Check sum

GPGSV messageThis message sends the information of all the visible satellites. The C/No is updated for all tracking satellites.

$GPGSV , t , n , xx , aa , ee , zzz , cc , aa , ee , zzz , cc , aa , ee , zzz , cc , aa , ee , zzz , cc *CS<CR><LF>

Field Detailst Total number of messages which is 3 alwaysn Message number (1 to 3)xx Total number of satellites in viewaa Satellite PRN numberee Elevation angle in degree. 00 to 90zzz Azimuth in degree with respect to true north. 000

to 359cc SNR of tracking satellites in dB. Null if not

tracking* Check sum delimiterCS Check sum

GPVTG messageThis message indicates the heading and speed relative to ground

$GPVTG , ddd . dd , T , ddd . dd , M , ssss . ss , N , ssss . ss , K *CS<CR><LF>

Field Detailsddd.dd Track degree 0-360T True Northddd.dd Magnetic track. This field is not validM Magneticssss.ss Speed in KnotsN Knotsssss.ss Speed in Km/hrK Km/hr* Check sum delimiterCS Check sum

Appendix - B

Factory Default settings

This chapter lists the factory default settings in the receiver. Whenever factory reset message is received, the following parameters of the receiver are initialized according to the table below.

Parameter Value

HCOM UART settings 9600 baud, 1 start, 1 stop, No parity, 8 of 8 format

Mask angle 5 degrees

Start mode Cold start

ON messages All NMEA messages

Message update rate Once a second

Datum WGS84

Fix update rate 1 Hz

Hdop limit 10

Position filter ON

Velocity filter ON

Extrapolation ON

Appendix - C

Datums

ID ELLIPSOID0 WGS 84 – Default1 Adindan – MEAN FOR Ethiopia, Sudan2 Adindan – Burkina Faso3 Adindan – Cameroon4 Adindan – Ethiopia5 Adindan – Mali6 Adindan – Senegal7 Adindan – Sudan8 Afgooye – Somalia9 Ain el Abd 1970 – Bahrain10 Ain el Abd 1970 – Saudi Arabia11 Anna 1 Astro 1965 – Cocos Islands12 Antigua Island Astro 1943 Antigua (Leeward Islands)13 Arc 1950 MEAN FOR Botswana, Lesotho, Malawi,

Swaziland, Zaire, Zambia, Zimbabwe14 Arc 1950 – Botswana15 Arc 1950 – Burundi16 Arc 1950 – Lesotho17 Arc 1950 – Malawi18 Arc 1950 – Swaziland19 Arc 1950 – Zaire20 Arc 1950 – Zambia21 Arc1950 – Zimbabwe22 Arc 1960 – MEAN FOR Kenya, Tanzania23 Ascension Island 1958 – Ascension Island24 Astro Beacon E 1945 – Iwo Jima25 Astro DOS 71/4 – St Helena Island26 Astro Tern Island ( FRIG ) 1961 – Tern Island27 Astronomical Station 1952 – Marcus Island28 Australian Geodetic 1966 – Australia and Tasmania29 Australian Geodetic 1984 – Australia and Tasmania30 Ayabelle Lighthouse – Djibouti

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Appendix - C Datums

31 Bellevue (IGN) – Efate and Erromango Islands32 Bermuda 1957 – Bermuda33 Bissau – Guinea Bissau34 Bogota observatory – Colombia35 Bukit Rimpah – Indonesia36 Camp Area Astro – Antartica (McMurdo camp area)37 Campo Inchauspe- Argentina38 Canton Astro 1966 – Phoenix Islands39 Cape – South Africa40 Cape canaveral – Bahamas, Florida41 Carthage – Tunisia42 Chataham island Astro 1971 – New Zealand43 Chua Astro – Paraguay44 Corrrego Alegre – Brazil45 Dabola – Guinea46 Djakarta (Batavia)

Indonesia (Sumatra)47 DOS 1968 – New Georgia Islands (Gizo Island)48 Easter Island 1967 – Easter Island49 European 1950 – MEAN FOR Austria, Belgium, Denmark,

Finland, France, West Germany, Gibraltar, Greece, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland

50 European 1950 –MEAN FOR Austria, Denmark, France, West Germany, Netherlands, Switzerland

51 European 1950 – MEAN FOR Iraq, Israel, Jordan, Lebanon, Kuwait, Saudi Arabia, Syria

52 European 1950 – Cyprus53 European 1950 – Egypt54 European 1950 – England, Channel Islands, Ireland,

Scotland, Shetland Islands55 European 1950 – Finland, Norway56 European 1950 – Greece57 European 1950 – Iran58 European 1950 – Italy(Sardinia)59 European 1950 – Italy (Sicily)

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Appendix - C Datums

60 European 1950 – Malta61 European 1950 – Portugal, Spain62 European 1979 – MEAN FOR Austria, Finland,

Netherlands, Norway, Spain, Sweden, Switzerland63 Fort Thomas 1955 – Navis, St. Kitts (Leeward Islands)64 Gan 1970 – Republic of Maldives65 Geodetic 1949 – New Zealand66 Graciosa Base SW 1948 – Azores67 Guam 1963 – Guam68 Gunung Segara – Indonesia, Kalimantan 69 GUX 1 Astro – Guadal Canal Island70 Herat North – Afghanistan71 Hjorsey 1955 – Iceland72 Honk Kong 1963 – Hong Kong73 Hu-Tzu-Shan – Taiwan74 Indian – Bangladesh75 Indian – India, Nepal76 Indian 1954 – Thailand, Vietnam77 Indian 1975 – Thailand78 Ireland 1965 – Ireland79 ISTS 061 Astro 1968 – South Georgia Islands80 ISTS 073 Astro 1969 – Diego Garcia 81 Johnston Island 1961 – Johnston Island82 Kandawala – Sri Lanka83 Kerguelen Island 1949 – Kerguelen Island84 Kertau 1948 – West Malaysia and Singapore85 Kusaie Astro 1951 – Caroline Islands86 L.C.5 Astro 1961 – Cayman Brac Island87 Leigon – Ghana 88 Liberia 1964 – Liberia89 Luzon – Philippines Excluding Mindanao90 Luzon – Philippines Mindanao91 Mahe 1971 – Mahe Island92 Massawa – Ethiopia (Eritrea)93 Merchich – Morocco94 Midway Astro 1961 – Midway Islands

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Appendix - C Datums

95 Minna – Cameroon96 Minna – Nigeria97 Montserrat Island Astro 1958 – Montserrat (Leeward

Islands)98 M'Poraloko – Gabon99 Nahrwan – Oman100 Nahrwan – Saudi Arabia101 Nahrwan – UAE102 Naparima BWI – Trinidad and Tobago103 North American 1927 – MEAN FOR Antigua, Barbados,

Berbuda, Caicos Islands, Cuba, Dominican Republic, Grand Cayman, Jamaica, Turks Islands

104 North American 1927 – MEAN FOR Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua

105 North American 1927 – MEAN FOR Canada106 North American 1927 – MEAN FOR CONUS107 North American 1927 – MEAN FOR CONUS, including

Louisiana, Missouri, Minnesota108 North American 1927 – MEAN FOR CONUS (West of

Mississippi river)109 North American 1927 – Alaska110 North American 1927 – Bahamas (Except San Salvador

Islands)111 North American 1927 – Bahamas (San Salvador Islands)112 North American 1927- Canada (Alberta, British Colombia)113 North American 1927 – Canada (Manitowa, Ontario)114 North American 1927 – Canada (New Brunswick,

Newfoundland, Nova Scotia, Quebec)115 North American 1927 – Canada (North west territories,

Saskatchewan)116 North American 1927 – Canada (Yukon)117 North American 1927 – Canal Zone118 North American 1927 – Cuba119 North American 1927 – Greenland (Hayes Peninsula)120 North American 1927 – Mexico121 North American 1983 – Alaska, Canada, CONUS122 North American 1983 – Centrla America, Mexico

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Appendix - C Datums

123 Observatorio Metereo 1939 – Azores (Corvo and Flores Islands)

124 Old Egyptian 1907 – Egypt125 Old Hawaiian – MEAN FOR Hawaii, Kauai, Maui, Oahu126 Old Hawaiian – Hawaii127 Old Hawaiian – Kauai128 Old Hawaiian – Maui129 Old Hawaiian – Oahu130 Oman – Oman131 Ord. survey G. Britain 1936 – MEAN FOR England, Isle of

Man, Scotland, Shetland Islands, Wales132 Ord. Survey G.Britain 1936 – England133 Ord. Survey G.Britain 1936 – England, Isle of Man, Wales134 Ord. Survey G.Britain 1936 – Scotland, Shetland Islands135 Ord. Survey G.Britain 1936 – Wales136 Pico de las Nieves – Canary Islands137 Pitcairn Astro 1967 – Pitcairn Island138 Point 58 MEAN FOR Burkina Faso & Niger139 Pointe Noire 1948 – Congo140 Porto Santo 1936 – Porto Santo, Madeira Islands141 Provisional S.American 1956 MEAN FOR Bolivia, Chile,

Colombia, Ecuador, Guyana, Peru, Venezuela142 Provisional S.American 1956 – Bolivia143 Provisional S.American 1956 – Chile (Northern, Near 900

south)144 Provisional S.American 1956 – Chile (Southern, near 430

south)145 Provisional S.American 1956 – Colombia146 Provisional S.American 1956 – Ecuador147 Provisional S.American 1956 – Guyana148 Provisional S.American 1956 – Peru149 Provisional S.American 1956 – Venezuela150 Provisional S.Chilean 1963 – Chile(South, near 530 south)151 Puerto Rico – Puerto Rico, Virgin Islands152 Qatar National – Qatar 153 Qornoq – Greenland (South)

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Appendix - C Datums

154 Reunion – Mascarene Islands155 Rome 1940 – Italy (Sardinia)156 Santo (DOS) 1965 – Espirito Santo Island157 Sao Braz – Azores158 Sapper Hill 1943 – East Falkland Island159 Sehwarzeck – Namibia160 Selvagem Grande – Salvage Islands161 SGS 85 – Soviet Geodetic System 1985162 South American 1969 – MEAN FOR Argentina, Bolivia,

Brazil, Chile, Colombia, Ecuador, Guyana, Paraguay, Peru, Trinidad & Tobago, Venezuela

163 South American 1969 – Argentina164 South American 1969 – Bolivia165 South American 1969 – Brazil166 South American 1969 – Chile167 South American 1969 – Colombia168 South American 1969 – Ecuador169 South American 1969 – Ecuador (Baltra, Galapagos)170 South American 1969 – Guyana171 South American 1969 – Paraguay172 South American 1969 – Peru173 South American 1969 – Trinidad & Tobago174 South American 1969 – Venezuela175 South Asia – Singapore176 Tananarive Observatory 1925 – Madagascar177 Timbalai 1948 – Brunei, East Malaysia178 Tokyo – MEAN FOR Japan, Korea, Okinawa179 Tokyo – Japan180 Tokyo – Korea181 Tokyo – Okinawa182 Tristan Astro 1968 – Tristan da Cunha183 Viti Levu 1916 – Fiji184 Wake-Eniwetok 1960 – Marshall Islands185 Wake Island Astro 1952 – Wake Atoll186 WGS 1972 187 Yacare – Uruguay

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Appendix - C Datums

188 Zanderij – Suriname

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Documents

GPS- User Manual