Hooligan
Member
For law enforcement these tracking devices can wind up on many
freqs and most are NOT gps technology based units. They are simple
radio direction finding type units that emit a carrier and some kind of
beep tone. The LEO vehicles have the tracking unit and antennas
(not talking lojack but similar) mounted in them.
They can be on just about any vhf-hi or uhf freq. Difficult to predict.
I am not saying there are no gps technology based tracking units out
there but they are not commonly used due to the difficulty in miniaturizing
this technology to the point it is small enough to not be noticeable to the
person being tracked and the fact that the tracking unit needs to be mounted
in such a place to see the sky to catch all the gps satellite signals.
Sorry, but your info is waaay outdated!
"Pinging" cellphones is the easiest way because it's passive. Covert device placed on the car is the other way. Device either just uses GPS to capture the movements of the vehicle until it's retrieved & the data is downloaded, or for real-time tracking it uses GPS/dead-reckoning for location fixes & then transmits that info out over the PCS/GSM mobile phone network to be processed & viewed on a computer display. Nice thing about that is you can get an alert whenever the vehicle starts moving, instead of having to have agents in the field watching the vehicle/monitoring the old-fashioned 'bumper-beeper.' You can also use the software to set up a 'geo-fence' so you get alerted if the target vehicle gets close to certain locations, etc. Modern GPS engines often don't need a direct view of several satellites for a good 3-D fix (& haven't for about a decade), though yes, there can be a loss of a signal in an underground parking structure or concrete canyon.
The modern bumper-beepers devices & various bait-packs are often found in spectrum which necessitates fairly large & obvious (or at least unusual) TDOA antennas arrays or a directional antenna & ideally a couple units for triangulation,so it's a little harder to be covert about it. Even if you've got a nicely decked-out surveillance van with disguised antennas, you have to ensure that the emitter is going to have a low probability of detection & not come thru the target's cheap car stereo system or be detected by the Close Call function of the scanner he just got.
In most cases, it's more cost-effective, accurate & safer to just ping a phone or infiltrate a GPS/PCS or GSM-based device & then remove it when you're done.