Thread: GPS vehicle tracking, any advise ?

Originally Posted by Danceheaven

I was thinking last night, (Careful i here you say), ricky if your using fsk to encode the nmea data and transmit it via gsm then decode it with a pic then feed this is to the com port on your local machine or tracking laptop if this comm port was set up as the comm for the gps reciever and you run say a mappoint or destinator wouldnt this show live tracking as in a exact duplication of the gps screen in the vehicle if it was running? or will the gps app need to initialsie the gps mouse first somehow?

Yup thats correct, "confused" did answer for me already

I have been testing it with mappoint and mapsonic all seems working well. I can only transmit a sentence once every 1-3 seconds depending on how long a sentence is...this is due to the fact the baud rate is reduced to 300 when transmitting over the phone. Of course some info is discarded so its not an exact duplication of the sentences...but it is more than enough for following the thief. I know some tracker can only update once evey 30sec or so.

At the moment Im working on filtering the incomming sentences from the GPS so only the important one is processed such as :

$GPRMC,$GPGGA,$GPCSA,$PGGSV

The location update is once every 3 seconds (maximum rate for $GPRMC at 300 baud). Ill like to insert some other sentence from time to time such as the number of locked on satellite, speed and some other info.

Im still not happy with 3secs location update though, so I may try to push the FSK baudrate to 1200 if the mobile can still handle it. Ultimately Ill like a once every sec location update. If I can find a sentence compression/decompression or implement a routine for the PIC I may do so...we will see.
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When you say you can communicate both ways through dtmf, how you planning to decode the tone at your end? I know a PIC can do it but it can be calculation intensive and wont have much processing power left to do other things. I have seen those dedicated dtmf decoder though

have you guys seen this?

http://www.directions.ltd.uk/products.php?cat=2

Yup, theres plenty out there but its the fun of making one that keep us going. They do normally cost around £300-£600. But for a £5-£10 add on to an existing phone/gps thats as good you cant really go wrong.

http://www.sacbee.com/state_wire/sto...11542277c.html

if we have any future questions on this subject, we should email this guy.

Originally Posted by trdcpu

http://www.sacbee.com/state_wire/sto...11542277c.html

if we have any future questions on this subject, we should email this guy.

Another GPS tracking application

Originally Posted by TrdCpu

:if we have any future questions on this subject, we should email this guy.

Damn!! You beat me to that post! It sounds like the guy had it set up pretty good, web site and all. Now if the guy was real hardcore, he would have figured out a way to hardwire the power for the phone

"The woman learned how Gabrielyan was following her when she discovered him under her car trying to change the cell phone's battery, police said"

I use Ham radio to track my car. I'll post some pics of the setup later..
You can track my car here:

http://aprs.saxgod.be/track.php?call=on4sax-9

For more info, google for APRS