Car tracking system using radio transmitter

hello friends
i just wanted to ask is there any kind of rafio frequency tracking system possible that uses freq. in the khz or mhz ranges and can tell the distance or direction of the radio transmitter located in a car somewhere
it would be so nice if you hace some circuits on this

Re: car tracking system

hello sibtain
that is a very good idea most of the car tracking systems are satellite based
for your problem i think you can use a microcontroller based system that can control the frequency and power of the transmitter located in the car
by telling the transmitter to change its power or frequency you can get a lot of help . of course you will have to use some kind of directional antennas that will rotate 360 degree checking where the maximum reception is ,if its same everywhee it can ask the transmitter to reduce amplitude or jump to a higher frequency once the direction is found things an get easier
you can also use 2 or 3 base stations that will look for the direction ,which once found can become the three corners of a triangle ,angles are known ,the distance between base stations is known you can also calculate the distance i think !
bye
hope this helps

Re: car tracking system

well thats a good idea but
is there any practical circuit implenting this kind of idea

car tracking system

well,I think you should use the direction finding antenna array. the circuit is not complicated.there're two kinds of methods for direction finding. one is using phase,another is amplitude. The main equipment you need is one receivers ,other things you need depand software to solve it.

Re: car tracking system

HAM radio operators have a solution in APRS, you need to be liscensed to use it (it works on 2 meters) and whats nice about the ham solution is there are already digipeaters in place, however you could use the same APRS system on FRS radios, however you then no longer have the infrastructure.