GPS Good for a Laugh But Has Serious History
Just about every type of consumer technology is good for a laugh now and then. OK, maybe more often than that. GPS navigation is an easy target, what with those cheesy voices and terrible street-name pronunciations.
Maybe the writers should learn something about the history of the technology. By now you surely know about GPS fleet tracking for your company’s service vehicles. Well, you can thank ancient mariners, the U.S. Air Force and former President Bill Clinton for making GPS available to track your fleet in real time.
GPS technology has come a long way since it was made available to the general public in the early ’90s. The roots of the Global Positioning System can be traced to the mid 1700s. That’s when the Royal Greenwich Observatory in England offered a cash prize to any engineer who could design an accurate clock that could be carried on a Royal Navy vessel as a reliable means for fixing its latitude and longitude on the earth, as well as distance traveled. The scientists at the observatory didn’t know it at the time, but they were on to something big: Accurate timekeeping was the key to creating GPS technology.
Fast-forward to 1993: The Air Force launched the 24th satellite in its space-based GPS network—the final satellite needed for the system to provide worldwide coverage. Six additional satellites joined the network over the next three years. Three “spare” satellites can be pressed into service if any of the 24 main satellites malfunctions or requires maintenance.
This “satellite farm” is situated 12,000 miles above Earth. Each satellite makes two complete rotations every 24 hours, in orbits arranged so that no matter where it is on the planet, at least four satellites are visible to any GPS fleet tracking or navigation device.
Each GPS device on Earth employs a technique called three-dimension trilateration to determine its position in relation to the three satellites used. Based on the extremely accurate atomic clocks on the satellites, a GPS unit determines how far it is from each satellite by analyzing the high-frequency low-power radio signals they transmit. The signals contain a pseudo-random code that both the GPS receiver and satellite generate daily at midnight.
When the satellite signal reaches the receiver, the receiver factors in the time code vs. the time the signal was received. Then it calculates the difference between the two to determine the unit’s distance from the satellite. It repeats the process with at least two additional satellites to determine latitude and longitude, and even elevation.
The signals broadcast from the GPS network originally contained an unencrypted signal-degradation pattern to make them inaccurate by up to several miles in civilian use. The military, however, employed an encrypted signal that was very accurate. In the 1990s, Clinton was convinced that the technology had many valuable uses in civilian life, and signed an order removing the degradation.
Fortunately, you don’t have to worry about how the technology works when deploying a GPS fleet tracking system across your fleet. All you need to know is that it works—to streamline fleet operations, improve driver productivity, keep a lid on fuel costs and assist in vehicle recovery. Learn more.
