Indeed there are several systems that are in use. Mainly these
systems are used for vehicle tracking, especially with regards to
police rescue of vehicles after they have been stolen.
I live in the UK, and for many high-performance vehicles they
insurance companies will not insure you unless you have a tracker
installed. There are several GPS tracking companies, some UK based,
some worldwide, and some US-only. Since I am unsure where you are
located, I have included all that I could find.
Cost: £23.50 per month (Aprx $35 per month)
What it does:
The unit installed in the vehicle sends a message to the RAC National
Control Centre at Haymarket every 20 seconds, including the lattitude,
longitude, speed and direction. The National Control Centre will
alert the police if the vehicle is stolen, and provide them with
Maxon TrakM8 Standard/Pro
Cost: £400 - £500 (Aprx $600 - $750) for the unit.
What it does:
The unit is installed into the vehicle, and includes a mobile-phone
SIM card. This allows it to contact a pre-defined mobile phone if the
alarm goes off, if the vehicle is driven outside a certain area, if it
is driven outside a curfew time or on various other circumstances.
Location: US / Worldwide
Cost: From $495 - $2575
What it does:
SpookTech offers a wide variety of vehicle tracking and tracing
solutions that can be used covertly or overtly to track vehicles.
They claim to have the lowest priced vehicle tracker, the Datalogger
II - The Scout. The hardware can be used anywhere with an appropriate
location database, and is intended to track where the vehicle has been
as opposed to offering security and tracking once the hardware has
Datalogger II - The Scout
Non-Vehicle GPS tracking
For expensive items, a discreet GPS tracking unit appears to be a very
good system. However, despite searching extensively, there do not
appear to be any specific systems for customer based non-vehicle use.
However, many of the vehicle units can be adapted to fit inside common
items required for security (For instance, there is often a space
inside monitors or computers where the units could be located). GPS
tracking is definitely picking up however, so you can expect to see a
major push as the prices drop in the near future.
GPS tracking in the news
GPS tracking used to protect Portable ATM machines. Some major banks
are considering the use of GPS tracking software within a new design
of ATM being released (This is from September 1998, and so is probably
in use now)
How GPS Works
As an aside, I have found a couple of sites that deal with how GPS
works and what it takes to locate your position anywhere on the earth.
Trimble.com - How GPS works
HowStuffWorks.com - how GPS recievers work
I hope this information gives you some idea of the current state of
the GPS market, both in the US and worldwide with regards to GPS
tracking for vehicles and security.
gps security tracker vehicle
gps security tracker -vehicle -car
how gps works