Home . GPS . Download . Business . Partners . Contact . Family . AVL . Links . History . AsOnTV . Forum

CHASE and AVL - remote tracking with the GPS Software

GPSS chase

Updated Saturday 4th September 2010 UK time

"where has that vehicle been every minute last week ?"
"where is he now, and what is he doing ?"

are you new to AVL and remote tracking ? see the AVL Needs page.

GPS/GSM AVL hardware AVL software on PC This "AVL" page explains how GPSS, the GPS Software, is used for remote tracking.

GPSS is run on a PC which could be in the user's home or office. The GPS is part of the AVL hardware which is fitted to the car or truck to be tracked. A PC is NOT needed in the vehicle.

GPSS communicates with the AVL hardware through the mobile telephone network, or some other communications system such the Inmarsat, ORBCOM, Iridium or Thuraya satellite systems. In recent years the lowest cost solutions use the mobile 'phone network.

Trackers are becoming small enough to be used as "personal trackers" to follow people, animals, or other objects: not just cars or trucks.

use of Pocket PC GPS and TR-101 tracker

Remote tracking using GPSS on Pocket PC ...

A simple example is where the target being tracked has a small personal tracker like the TR-101 planted on it. A text message from a mobile 'phone will result in the tracker responding with a text message within typically less than a minute.

The text message from the tracker will include a latitude and longitude in decimal degrees. e.g. 51.3968 -0.6603. This could be looked up on a paper map, with a grid of lat/lon lines printed on it, such as from google earth. Or you could type it into google maps if you are online.

But you can also just type the lat/lon into GPSSppc running on the Pocket PC based GPS. The destination will then be placed on the maps at the target location, and you will be guided to it.

The information below is for the more direct, but technically more difficult, automatic live tracking.

Chase using bluetooth Sham in Staines' picture It seems any Pocket PC based GPS with bluetooth could be used with a bluetooth 'phone to use GPSSppc for remote tracking in "chase" mode. For an introduction to GPSS for the Pocket PC see the GPSSppc page, and the brief GPSSppc User Guide.

Sham Bahri has managed to get GPSSppc working in "chase" mode, by using GPSSppc running on a Pocket PC based platform, receiving both local GPS and remote GPS data over bluetooth. Details are: T-Mobile Vario (WIZA200) Smartphone running GPSSppc v9m under WM6: Holux Slim 236 Bluetooth GPS on COM 8 at 4800 and Remote Tracking using Sony Ericsson K800i phone as a modem on Bluetooth COM 7 at 9600. More information on work by Sham getting GPSSppc remote tracking to work on Pocket PC based smartphones is on the ChasePPC page.


For the majority of applications the GPSS PC may be fixed, within home or office. However, it may also be mobile, as a Laptop PC which can be taken to a potential customer for demonstration, or used near the target vehicle for "chase".

TV Screen GPSS chase If the Laptop (or Car-PC) has a GPS, then GPSS can be used in it's simpler "navigation mode" - showing your own location on the map, and providing voice guidance to a destination. If GPSS is switched to "CHASE" mode, it will show two symbols on the map: your own position, based on the GPS directly connected, and the target location, based on data coming in over the 'phone network. The Laptop must obviously have a suitable modem for this. In CHASE mode GPSS will show both vehicles on the moving maps and treat the target as a destination. i.e. the driver will receive voice guidance to the target - which could be moving. UK Police were among the very first users of GPSS for Covert Tracking. i.e. tracking of a vehicle without the driver knowing. The picture on the right was from the "Put It To The Test" UK Television programme, first broadcast in 1996, which is on our AsOnTV page.

communications are important ...

Some applications or countries may require alternative communications to be used: BBCTV Centre
For ORBCOMM Low Orbit Satellite communications, see the ORBCOMM page.
For Inmarsat-C satellite communications, see the INMARSAT page.
For Thuraya satellite communications, see the THURAYA page.
For use of other radio communications, see the RADIO page.
For phone-to-phone tracking, see the Where R U page.
For use of GPSS with GSM SMS, see the SMS Page
For a strange example of web based tracking, see the Bottle Story page :-)

GPSS can be used with any one, or any mix of the above communications systems. When GPSS is used in "multi-vehicle tracking" mode, it shows each of the vehicle locations on the maps. The "Vehicles Tracked" summary shows a line for each vehicle, and more information such as status, decoded text messages, pictures and/or sounds, can be retrieved simply by clicking on the summary or vehicle symbols. Text reports may also be generated from stored GPS data.

Alternative 'Direction Finding' Technology

small bug on bird Small "bugs" or radio beacons have been used for years to track animals or used as low cost car security devices. See the Direction Finding page for how a computer and GPS can be used to triangulate and chase the transmitter on the car, person, animal or bird. This DF technology was first televised in the UK when Meridian filmed GPSS being used to find escaped falcons. See the Finding Falcons page. These devices have the advantage of being cheaper, and much smaller. The disadvantage is their range is normally only a few miles, so they need to be "hunted down" with a suitable DF receiver.

a message from Robin ...

Robin Where is my driver ? We do not sell hardware or complete solutions. We simply licence others to use our GPS Software, GPSS.

If you wish to sell this type of remote tracking system, or build it yourself, please visit the business Page. You will see that I ask you to get what I call "the minimum tools of the trade" - a Laptop PC and a GPS, and test GPSS with GPS before contacting me via the "Quiz" on the download page.

It is best to start simply, testing GPSS in it's simplest "navigation" mode, with the GPS connected directly to a Laptop PC running GPSS. After adding mapping for your country, you can then move on to remote tracking tests - with my help.

Anyone in business is welcome to make one initial 'phone call to me, using a number on the contact page, to establish if GPSS will be of any use to their business, before investing time in these steps.

The steps we normally go through with new business contacts are:
1. Free use of GPSS, and support from me, while you test the software, with real hardware, and demonstrate it to your existing business partners.
2. Purchase of a GPSS Demonstration Licence to enable you to demonstrate GPSS to possible future investors, partners and customers. This is an important step for us both.
3. Selling or exploiting GPSS-based solutions within an agreed framework.

We encourage our business partners to collaborate rather than compete, and I do not issue demonstration licences lightly.

GPS Software on Pocket PC Our large network of "enthusiast" GPSS users can also often be of great help - particularly to those involved in export from their own country. These enthusiasts also help us test new developments such as GPSS for the Pocket PC which now supports "chase" on suitable Smartphone products.

I look forward to speaking with you soon.
Robin Lovelock
Sunninghill UK, January 2008.

Partners licenced to use GPSS

You will find information on these companies on the partners page.

GPS + Mobile Phone for Covert Tracking

Falcom stepp Many Ways In recent years the most popular technology for remote tracking involves a combination of GPS receiver and mobile 'phone.

The GPS and 'phone will normally operate through glass, plastic or fabric, so is not difficult to install (e.g. hidden near front or rear window).

It just needs a 12 volt supply, from the car battery. Typical current drain is between 0.05A and 0.2A, depending on the product and whether the GPS is switched on (e.g. from the vehicle ignition). So even a small car's 35AH battery is often sufficient, without installing more complex power-saving devices. Some companies obviously specialise in hardware more suitable for covert installation. e.g. inclusion of the battery.

AVL hardware products, such as the Falcom STEPP shown here, include "intelligence" in addition to the GPS and mobile 'phone electronics. i.e. they include a processor and memory to allow the product to be used in a number of different ways.

One of the most useful features is to store the GPS locations for a number of days, even if the vehicle is not in communication with the GPSS PC. This often provides the lowest cost solution to the requirement, "where has that vehicle been every minute last week ?". i.e. GPSS makes communications contact and downloads the data when it is needed, avoiding the expense of minute-by-minute tracking. The user can also answer the question, "where is the vehicle now ?" whenever they wish.

Hardware Components for AVL and Covert Tracking

S-911 from Laipac G-19 from San Jose Nav There are now many "GPS/GSM" products becoming available of smaller size amd lower cost - such as the S-911 Personal Tracker from on the left. Other examples are the G-19 Trackstar from (on right) and the GT03 (Personal tracker) or GT02 (vehicle tracker) from or their distributors (below). Globalsat have the TR-101 personal tracker, shown here on the left. Globalsat have been on our Partners page for years, and their TR-101 is here. Typical cost of these products, for one-off purchase including the distributor's markup TR-101 is in the ballpark of 100 GBP/Euro/USD. Shop around and you may find new products at much lower prices - but be careful you know exactly what you are buying. GT03 Personal tracker and GT02 vehicle tracker

For years many GPSS-based vehicle systems were delivered using the Falcom A2 GPS/GSM unit pictured on the left. In recent years this was replaced by the Falcom STEPP seen further down on the right. All these products include both GPS and mobile 'phone electronics in a small container. Falcom A2 Falcom is based in Germany on Scan Projects Solutions in Denmark, on supply hardware including modified Falcom units able to download stored GPS data to GPSS (see testing section below). Falcom stepp This capability can now be found in more recent Falcom products such as the "STEPP". This supports both dialup facilities including recorded history using the SIM card data line and SMS capability using the voice line (see "the SIM card" below). Distributors for Falcom products include Sequoia in UK on You can see their Falcom STEPP page here. Azzurri in UK, once appearing on this page, no longer distribute Falcom products. Be careful what you buy. See "STEPP2 Problems" below.

Before buying any product, ask the supplier if it will work with the GPS Software from
If anyone knows of other products, well-proven with GPSS, please let Robin know via the contact page so he can update this section.

Products such as these include three elements to construct the GPS-'Phone device: 1) the GPS receiver with it's antenna; 2) the mobile 'phone electronics with its antenna; 3) electronics to connect (1) and (2) and provide "intelligence". Garmin 35
For years the most popular GPS component for covert tracking seemed to be the Garmin GPS35 - see the picture on the left. This can be setup to output at a different speed to standard 4800 for NMEA. e.g. 9600 for GSM and 1200 for analogue. It can also be setup to output only the $GPRMC sentence, which carries location, speed and heading. Voxson Another popular device was the Siemens M20 GSM Modem, which combined items (2) and (3) above within one package. The M20 may be purchased from TDC in the UK on fax 44 1256 332810 or e-mail Distributors of the Wavecom in France is also a manufacturer of GSM modems popular in this market. Garmin GPS35 and other GPS receivers may be found on the GPS page. Voxson in Australia on had a complete solution to compete with the excellent Falcom products. Version 5.5 and later GPSS.EXE supports the Voxson +LOG recorded data feature. Commands to download stored GPS data from Falcom or Voxson units appear within the section "Testing of GPSS with GPS/GSM" below.

itrac The iTrac units by Cheng Holin in Taiwan are being used with GPSS by Secure Tech International, listed on our Partners page. GPSS v6.6 and later supports the proprietory &GPS message format used by the iTrac, instead of the preferred industry-standard NMEA GPRMC format. This was the result of collaboration between Secure Tech and Sunninghill Systems. Technical Specifications on the iTrac are available here.

STEPP2 Problems

The Falcom STEPPII does not include "built in" capability found in earlier Falcom products such as the A2 and first STEPP.

Falcom, based in Germany, have been making good, reliable GPS/GSM products for many years, and have been supplying these products through their distributors into many of the 160 countries in which GPSS is now used. All these products, including the first STEPP units, could be used "straight from the box", with the required software and default settings already available. These simple, default facilities included:

  • the automatic answer of a data call from any modem with live NMEA GPS data (typically $GPGGA and $GPRMC sentences).
  • the automatic reply to a polling SMS such as "&REQ POS" from any mobile phone or GSM modem with texted NMEA data.

These "built in" default facilities, which only required the solution provider to insert a SIM card and apply 12v power, made the Falcom product line very attractive. The more sophisticated features, such as following up a direct GPSSDIAL.CFG connection with downloading stored "history" data, or configuring the product to make a text position report on a regular basis, or in response to a closed switch - were not difficult to configure - IF needed for the particular application. The advanced features, if needed, could be setup using a simple data cable and software plus documentation downloaded from the Falcom web site.

The more recent STEPII product is being supplied without this built in default capability. Furthermore, it seems that the process to do the required loading of parameters, and maybe even software, cannot be done with a simple serial data, but may require a "starter kit" costing two or three STEPP units. It is understood that the STEPII has many additional features, not found in earlier Falcom products, but that of replying to a text from any 'phone will not be available until the next software update, planned for March 2007.

If you intend using the STEPPII with GPSS, have your distributor configure it for you, or make sure you are capable of doing it yourself.

getting a SIM card

These GPS/GSM tracking products need a SIM card - as does any product that exploits the mobile 'phone network. Some suppliers will include a SIM card, but many will not. If the product is only using SMS then almost any SIM would do, the text messages going on the voice line. However, some products like the Falcom STEPP support both SMS based reporting and direct dial-up connection. For this the SIM should also have a data line. Solutions will vary between country and 'phone network provider, including some where there is a regular subsciption cost (a "contract") at perhaps 5 GBP/month or more. One of the lowest cost options is a "pay as you go" SIM, but you need to make sure there is an outgoing text (or 'phone call) every few months, or the network may "switch it off". Remember your GPS/GSM product might only be receiving calls from your GPSS computer, and therefore not "spending money" with the SIM provider. One option I've tested with success in UK is to buy a pay as you go Vodafone SIM at 5 GBP (total), register it, then have a data line added, at no additional cost, other than perhaps 10 or 20 GBP of "top up" to ensure that the occasional outgoing texts (at least one every three months to keep it alive) do not result in it being switched off. i.e. the GPSS PC may dial into the STEPP, for second-by-second tracking, or retrieval of stored data. Occasionally this PC (or any mobile 'phone) sends an &REQ POS message to cause it to reply with a position report and spend perhaps 0.12 GBP.

Hardware vs Communications Costs

Costs Typical cost of hardware to be installed into each vehicle will obviously depend on the product, the distributor, and how many are purchased. However, in 2003/2004 the cost of hardware such as the Falcom STEPP might be as little as 350USD in one-off quantity. Remember that this does not include the cost of the "solution provider" travelling to a customers' premises and installing hardware into each vehicle - he also needs to make a profit ;-) The lowest cost solution may be a combination of GPS and mobile 'phone. The total cost is then that of the hardware, and the monthly rental of the 'phone. There will be an additional cost, for each 'phone call made, but this will be small if the number of calls is small. For many anti-theft or security applications this may be sufficient. If the vehicle owner wants to know where the vehicle has been, each minute of each day, this can achieved with memory in the hardware. e.g. the device might be called once per day, to download stored locations recorded every minute of previous 24 hours. The GSM Short Message Service (SMS) can be used to reduce the running costs for applications (such as Taxi Fleets) that require continuous minute-by-minute tracking of the vehicles. A GSM modem will then be needed on the GPSS PC - which could then also be mobile.

Getting Your First GPS/GSM Prototype

If you are a business, and have already visited the business page, got the minimum "tools of the trade" (Laptop PC and GPS for in-car tests), and registered with Robin, you may then be ready to get your first piece of remote tracking hardware. You might assemble it from components, or buy a complete hardware solution by mail-order (without GPSS or installation) from a distributor of Wavecom, Falcom, or others that build these hardware solutions.

You require a GPSS Licence


Those businesses who follow the procedure on the business page, are often granted a free licence, so they can test GPSS use for remote tracking.

The cost of GPSS licences depend on the application, and the quantity purchased.
Those who buy in quantity get a large discount.
Prices here are in GBP (Pound Sterling. 1 GBP = approx 1.5 USD)

The cost is 100 GBP per vehicle tracked - if 9 or less licences are purchased.
The cost is 50 GBP per vehicle tracked - if 10 licences are purchased (50% discount).
Purchase in larger quantities will cost less. The discount is negotiable.

This is for vehicles tracked via radio, ORBCOMM, GSM and other mobile phone systems.

In-Car navigation licence cost is less, at 20 GBP per vehicle, for purchase of 1 licence. So a "chase" car fitted with own GPS, chasing 1 vehicle, is 120 GBP (1 off cost).

Contact Robin for negotiation of higher volume purchase, or other variations such as Inmarsat-C, or where "air time" is being sold, rather than hardware. Our policy is to keep GPSS cost less than 10% of total end-user price - much less for those who buy in higher quantity.

The first licence purchased is normally the "Demonstration" Licence, at 100 GBP.
This permits you to demonstrate GPSS to others, and includes a listing below under "B", and configuration of GPSS with your own startup screen, etc.

Testing of GPSS with GPS/GSM


before you start testing ...

Please contact Robin. He will often grant free registration and help in other ways.
The Control-R registration text, replacing "UNREGISTERED", should be "TEST 1B9V Joe Bloggs" - where "Joe Bloggs" is your full name.

If possible, we suggest you start by testing GPSS directly connected to a GPS receiver, using the software and maps from the download pages. This GPS->Laptop PC use of GPSS can run UNREGISTERED. If you wish, you can do this BEFORE the Business Quiz questions are answered, and Robin gives you the key code.

You may wish to leave this "in-car" copy of GPSS unchanged (e.g. in c:\gpss04) and copy all files to another directory (e.g. c:\gpssx ) for remote tracking.

the SIM card - which number ?

The SIM card within the GSM modem will either have only a "voice line" number, or both "voice line" and "data line" numbers. They will have different numbers. Dial up tests below, which involve a direct connection between the GPSS PC and the remote GPS/GSM device, requires a "data line". i.e. this is the number that will be put into GPSSDIAL.CFG below. For SMS use with SMSH and products such as the Falcom STEPP unit, the "voice line" should be used. When testing a STEPP you may prefer to start with the SMS test since it could be done with just a mobile 'phone instead of a PC running GPSS and SMSH. i.e. you simply send a text message from your mobile 'phone containing "&REQ POS 0" to get a $GPRMC message back - depending on how the STEPP unit is configured.

first "dial-out" tests ...

You will need a modem, connecting your PC computer running GPSS to a telephone line. e.g. the one you use for Internet access. If the modem is NOT on COM1 (e.g. COM2) you must edit GPSS.CFG and change COM1 (e.g. to COM2).

You must also make a file GPSSDIAL.CFG holding the remote GPS/GSM unit 'phone number. An example of GPSSDIAL.CFG is :

- where 12345678 should be replaced by the telephone number of the device.

The duration of the call may be limited, such as the example below of 59 seconds,
by use of a file DIALTIME.CFG

When you run GPSS it will now display two buttons [Dial] and [Hangup].

Clicking on [Dial] will dial up the remote unit, using your modem, and the black lamp on the dial form will turn red. After perhaps 10 seconds, it should turn yellow, as a connection is made with the modem in the remote hardware. If there is a GPS in the remote hardware, the light should turn green, and a map be selected automatically to show the vehicle position. GPSS should continue tracking it, second-by-second.

If you wish, you can record the incoming GPS data for later analysis (with Control-A Form), by hitting the % key to create a NME File

Clicking on [Hangup] will terminate the 'phone call.


Thinking of using GPSS without permission ? If so, please visit the PIRATE Page.

Sending commands to Falcom or Voxson units

Some GPS/GSM units require to be send a "password" or particular command, before they will send back GPS data. Additional commands are used for things like requesting transmission of the stored GPS data (e.g. vehicle position every 1 minute for past 24 hours).

The Falcom STEPP unit would not normally require such a command, since it would respond with the GPS data as soon as the connection is made.

These commands can be sent manually, by adding buttons to the GPSS Dial Form. e.g. a second button labelled "LIVE" in GPSSDIAL.CFG

The user clicks on "Dial" as before, to make the GPSS PC dial out through the modem and connect with the remote unit. When the connection is made, the GPSS "dial light" will go from red to yellow. The user then clicks on "LIVE" to send the command "&REQ INT" to the Falcom unit, which should then immediately respond with live GPS data (light goes green).

The equivalent command for a Voxson unit might be:
- to start live data transmission, or
STOP LIVE,AT+WDMOD=0_0_0_1_1_1
- to stop the data. The Voxson unit would remain in this state, so could be configured to reply with live data when the connection is made. However, this may not be best if recorded data is to be retrieved from the unit - the user might be confused by what is live and what is recorded.

Use of other files, like CONNECT.CFG, AUTOREC.CFG, HANGUP.CFG enable you to configure GPSS, so only one button might be needed in GPSSDIAL.CFG for each vehicle tracked.

You can make GPSS do the LIVE automatically, by adding a file named CONNECT.CFG holding:
dial,ATDT12345678,&REQ INT

Before dialling, you can start GPSS recording by hitting % key. (so the recorded GPS data can be plotted later with Control-A) You can make GPSS start recording with the % key automatically, by adding a file name AUTOREC.CFG holding:

data will then be recorded to FREDB001.NME, then FREDB002.NME, etc.

Some Falcom-based systems like to be configured so that they are sent a command telling the remote unit to hangup the line (although this should happen automatically when the line is hungup from the GPSS PC end). You can make GPSS do the remote REQUEST HANGUP automatically, when you click on the Hangup button, by adding a file named HANGUP.CFG holding
dial,ATDT12345678,&REQ HANGUP
(if you wish the Falcom unit to hangup the line at the vehicle end)

Some Falcom units, such as those from Scan Project Solutions in Denmark, can store the GPS data for later retrieval at high speed by GPSS. The data might typically be stored every 1 minute, or when the vehicle has moved another 100 yards - so several days movement can be retrieved when wanted. i.e. to answer the user's question, "where has my vehicle been every minute in the past day ?".

For Falcom units the command line in GPSSDIAL would be:
and for Voxson units it would be:

Configuration of GPSS for remote tracking

GPSS has a very "open" design, and changes can be made in how it behaves by the simple removal, addition, or change to files, including WAV sound files. e.g. "let me show you something I did earlier" is implemented by playing the sound file LETMESHO.WAV, so removal of this file will remove this spoken message. If GPSS does not receive GPS data, it reads data from the file GPSS.NME which simulates incoming GPS data and operator keystrokes. So replacing this file by a simpler one (e.g. NOTHING.NME) will replace the demonstration by a default map (or picture).

Here is a checklist of typical changes to GPSS for remote tracking:

  • addition of GPSSDIAL.CFG for direct dial-up use described above.
  • addition of SMSH to handle incoming SMS messages.
  • replace GPSS.NME by NOTHING.NME or an alernative.
  • removal of LETMESHO.WAV - "let me show you something I did earlier...".
  • remove or replace $$$START.WAV - "This GPS software is given free to individuals ..."
  • removal or change to other sound files.
  • addition of $$$START.BMP (640x480x256 colours) with your own startup logo.

Configuration for Multiple Vehicle Tracking

For technical information of Multiple Vehicle Tracking with GPSS, please visit the MVTECH Page