GPS Vehicle Tracker

GPS Vehicle Tracking

A "technology demonstrator" was required to test the feasibility of using GPS recording in so-called "road pricing" schemes.

Early generation schemes relied upon "beacons" mounted at the roadside and transponders in the vehicles, or automated number plate recognition (ANPR) - but these require costly roadside infrastructure. Logging the position data from a GPS receiver should allow road usage to be recorded with no roadside infrastructure at all.

For the initial phase, we used a Fastrack Supreme modem (predecessor of the Sierra Wireless AirLink FXT) fitted with an "IESM" plug-in card to provide a GPS receiver and IO signals - including an SPI bus to allow connection to an SD Card for data recording:

Fastrack "test-bed" for SD-Card operations

We created an Open-AT application with Wavecom's "Companion GPS" (CGPS) plug-in, and used the popular FatFs open-source FAT file system for managing files on the SD Card, developing a custom driver for accessing the SD Card via the SPI bus. We took advantage of Open-AT's multi-tasking features to ensure that accesses to the SPI bus did not block the GPS processing.

GPS Track of a drive on the Lizard PeninsulaThe use of an SD Card and FAT file system allowed the data to be easily transferred to a PC for analysis.

For example, the image to the right shows the recorded track data from a drive around the Lizard Peninsula in Cornwall, as displayed by Google Earth.

(click the image for a larger view; the track is shown in blue).

 

The application was then ported to the Client's custom hardware platform - using a Q2686 module with the GPS chipset, SD Card, etc, integrated into a single unit. 


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