Aug/Sept 2008

You can track vehicles or assets anywhere in the world without using GPS or satellite location, using only the mobile network SIM card in the remote tracking device, under a system launched by UK-based telemetry specialist Podsystem. The company says it is not aware of any similar system currently available in this country.

The system uses cell ID location, in which the position of a device is calculated in relation to its proximity to mobile phone masts in the area. It's a familiar and well-established concept, but applications are generally limited to the country where the user is based. Truly international cell ID tracking systems are rare because of the cost and the problems of 'roaming' among multiple network providers.

Podsystem has avoided these problems by developing a system that requires no feedback from foreign network providers. It explains that SIMs in GSM-based devices automatically report on their current cell ID and signal strength wherever they are in the world, and this information can be captured by software developers using standard 'AT' commands.

The clever bit is being able to identify the physical location of the device from this information, and Podsystem has been working with various suppliers who have built up worldwide databases of cell mast locations.

The net result: Podsystem says it can usually work out the position of an asset almost anywhere in the world to the same degree of accuracy as GSM tracking within the UK. That might range from a few hundred metres to several miles, depending on the density of mobile masts. 'There are a large number of tracking and telemetry applications where this degree of accuracy is perfectly adequate,' says managing director Charles Towers-Clark.

He sees the system having twofold appeal – either as a back-up to GPS tracking, where GPS signals might be lost when devices are indoors but GSM signals might still get through; or as a stand-alone system where pinpoint accuracy is not a requirement.

Telematics and telemetry system suppliers are expected to be among the most enthusiastic takers, but end users who can see a benefit are being encouraged to ask their supplier for the service. Charles Towers-Clark says it should be 'relatively straightforward' to integrate it into existing tracking software and mapping.

Particularly appealing is the price, which has been pitched at £2 per unit per month, with unlimited positioning fixes. This is very much cheaper than the typical GSM tracking prices charged by the mobile network operators themselves, especially for international applications.

Podsystem offers network-independent SIMs to telematics and tracking system suppliers as part of its existing portfolio, but says its new international tracking system should work with almost any SIMs, whether the company supplied them or not.

Currently the system is limited to data-only remote devices. Towers-Clark says tracking standard voice-call mobile phones abroad in this way is more complex, 'though it's not impossible.'