Pop Quiz … How Many Things Is GPS Tracking, Right This Minute?
Don’t get a headache, it’s a trick question you already know the answer to … easy, actually. The correct answer is, none, nothing, nada, zilch, don’t got none, never done it, never will. In spite of everything we seem to read, watch on TV and see in the movies understanding the overall technology will be a lot easier if you just remember one essential fact … GPS does not track ANYTHING!
GPS satellites send out a precise timing signal that enables a GPS receiver to calculate the distance (as a function of time) from each satellite. Once the receiver has a “good enough” signal from at least four “birds”, the receiver then knows where it is in three dimensional space. That is what the GPS system … the “Space Segment” (the satellites on orbit around the earth) the Ground Segment (the monitor and control stations spread around the globe) and the Control Segment (the dedicated folks out at Schriever AFB on the barren plains of Colorado) delivers to a user. “Only this and nothing more” quoth the Raven. (actually it was the Raven’s host who said that but this is about GPS, not poetry)
Once the GPS receiver knows where it is, you can track the receiver’s location by somehow sending the coordinates over some sort of comm system … but you can’t “tap into” the GPS system and “see” where anyone or anything is. GPS “tracks” nothing. Why am I being so pedantic about this? Easy, because the number one problem I’ve seen in working with tracking systems over the past 10 years or so is unrealistic user expectations.
GPS actually performs technological near-miracles every second of the day, but if you want to use GPS to track your commercial fleet, tell passengers when the next bus is due, find out where your teenager is and how fast he’s driving or even get directions to a restaurant, you have to:
- Understand the basics of what the system is
- Know something about the _other_ systems involved … communications networks, maps and databases
It is those “other systems” which actually produce useable information. Make sure you buy what you need and what can realistically perform to your expectations. GPS, alone, just produces coordinates in space.
The GPS Review posted a great article on user expectations today, it would be worth your while to read it, I found it very well written.
Sorry, got to run, something is tapping at my door ….