Gps Two Way Tracking
question about gps?
we all talk about gps receivers, i will call this oneway connection? Can we establish two way comunication with gps? for example how those companies which offer gps tracking services such as lojack are able to access or ask satellite to located tracking divice number xxxx.. How those companies actually establish connection with the satellite? what software or protocol do they use….or are this services given by the us department of defence for such companies?
I’ll appreciate any comment,
luis
First of all, ‘LOJACK’ does not use GPS to track stolen cars. When someone reports a vehicle stolen, a signal is sent to the vehicle, (in the VHF – UHF) range, then the unit sends out bursts of it ‘locator’. This does not give out a position. If you notice, many police cars are equiped with LOJACK locators. There are 4 antennas on the roof of the car..When they are near the signal, it will triangulate the position of the car, and it can usually be found in the area, the accuracy can be within a block or so, depending on terrain. The vehicle transmitter puts out a low power signal, sending it’s ‘ID’, like ‘A63451′. They have a round readout in the car which looks like a compass, pointing to the direction of the signal, when they are near it.
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