GPS Tracking ROI

A number of recent searches have been looking for “defeating” GPS.  Not sure if this is just general interest, or if people are looking for which wire to cut to disable a specific make and model of tracking unit.  Either way, here’re some thoughts.

First of all, a lot of information and a great deal of unfounded hype circulate on the Internet about defeating the entire GPS … world-wide or at least over a larger land area.  Indeed, the US government has plans and programs in place that can deny access to the system, with varying degrees of success.

However, since I’m no longer intimately involved with this, as I once was, and since much of the information is classified, we won’t go any farther down that road.  To deny use of the GPS over a wide area or to large group of users is not easy.  To deny use of the system to one group while allowing others to have access is also not easy.  Originally the system architects thought they would be building a system that was really two systems, a public use segment and a military or official use segment that would require users to have decryption codes, sent out under government control.

Well, they actually did build such a system, but the “official” segment is now, to general users, merely and asterisk.  The capabilities of the publicly available system are now orders of magnitude better than originally expected, so denying public use to the small “official” segment really doesn’t mean much.

To deny access to over relatively small areas is not hard at all … but it requires electronic equipment not likely to be in the average person’s storage shed, and is going to be highly noticeable to other spectrum users and thus short-lived.  The GPS signals are very low strength and all concentrated in a single, readily accessible area of the electromagnetic spectrum, so it’s not very challenging to design jammers that will work over small areas.  I think, though, that the “defeat” queries are looking more to deny owner’s access to information from individual tracking units, or so I opine.

Any brand of GPS vehicle tracker consists of three major components.  A power source, an antenna to receive signals from the GPS satellites and a method to move the data collected and temporarily stored in the tracker to the ultimate end user of the information.  The vulnerability of these components varies, but all have some degree of susceptibility.

First we can look at disrupting the signals from the sky to the “brain” of the unit.  This will certainly deny any useful information at the source.  Nothing tracked at all will mean no information at all, good or bad.  But of course, this is rather brute force and won’t be able to make the driver look as if he’s going about his work while he’s actually spending the afternoon with his girlfriend.   Depending on the unit in question, the antenna may be a separate component (mounted on roof or windshield) or integrated into the main package.  Anything that denies the antenna a view of the sky will serve the purpose.  I’ve seen drivers trying aluminum foil over the antenna, an empty tuna can over the roof mount antenna, and the most common …continually loosening the antenna lead so that it falls off or makes bad connection nearly everyday.   To combat these common curses look for a system that continually monitors the signal from the antenna and instantly makes a record of date, time and location where signal is lost, and then regained.

I worked an issue with a user involving a recalcitrant driver who was shielding the antenna, driving around form a while and then returning to the same location, unshielding the antenna and going back to his appointed rounds.  Management wasn’t noticing at first until we ran a report to show gaps in time… make sure any unit you’re thinking of buying tracks time continuity.

Loosening the antenna wire was a nice vandalistic touch, since in that case it was a government system maintained by a contractor and as the system manager; I was paying about $100 in troubleshooting fees every time a trouble call came in.  To combat this we came up with an excellent material widely used in aircraft maintenance called Torque Seal putty. (Most aircraft maintainers refer to this by the more descriptive name, “Bird Shit”).  Actually this stuff is properly called: SAF-T-EZE TORQUE-SEAL and is manufactured by the STL COMPOUND CORPORATION in Lombard, Illinois.  You complete and test a connection and when sure everything is working right, squeeze out a dab of Torque-Seal and it hardens into a little lump on the connection.  It servers a dual purpose … it physically prevents the connection from vibrating loose … it requires a noticeable amount of force to remove the Torque-Seal, and it provides near-absolute proof that the connection has or hasn’t been tampered with.  Another technique that’s useful is to mount units, where possible, well out of reach.  On Ford trucks, for example, the  radios pop out in seconds with a special tool and required wiring is easily accessible allowing the unit to be connected and strapped in place and the radio re-installed, making it safe from tampering except for those much more determined that the average casual “slacker.”

Reviewing what I’ve written here I feel I could go on and on, but in addition to being boring, it would serve little purpose.  Any device made by man and installed by man can be defeated by man.  It’s really, really hard to make a foolproof system because fools are so damn ingenious.

My own suggestion is make your GPS immune to driver sabotage and interference by:

• Making the drivers part of the decision-making process
• Making GPS part of a pay for performance process …such as bonuses for ton miles delivered, miles of streets swept per hour, passengers carried per hour, etc.
• Making the driver’s GPS record part of each performance review.