Okay, so GPS 3.0 isn’t technically a real thing, but a new third generation of GPS (or more globally GNSS) really is on the horizon and it will bring with it unprecedented accuracy for a whole host of locations and position-based applications.
Let’s look at a little GPS history. GPS was first designed by the DoD starting way back in 1973 to meet the military’s crucial need for very accurately locating nuclear assets in the dangerously unstable global political environment of the Cold War. Accuracy being relative in this case. First-generation military GPS receivers could achieve accuracies on the order of meters using the GPS system’s high accuracy signal, but the military reserved these for its own use and allowed consumer receivers to use only a lower accuracy service (Selective Availability) which limited location fidelities to tens of meters. In the summer of 2000, President Bill Clinton directed the DoD to allow civilian access to the higher precision signals, and a whole new generation of consumer products followed. But location accuracy today for most receivers is still hampered by several different sources of error which limit precision to several meters.
GPS signal is subject to several sources of errors
Errors generated at the satellite end of the link include ephemeris errors (orbital estimates) and clock errors. At the receivers, the errors include clock errors, multipath propagation, and ionospheric dispersion. In today’s receivers, the largest of these contributions is the ionospheric effect.
Beginning in 2005, a new constellation of satellites was launched that broadcast a 2nd civilian signal on a different frequency band. The effect of the 2nd signal is to allow receivers that can receive both frequency bands to nearly eliminate the effects of the ionospheric delay. A dual-band receiver today can converge to decimeters or even centimeters of accuracy. So if the 2nd frequency band was activated in 2005, why is it only “gen 3” now? Dual-band receivers have been available for some time but their prices made them suitable only for high-end commercial applications such as surveying and agriculture (a modern combine is a surprisingly high tech machine). Only within about the last 2 years have low cost, dual-frequency GPS receiver ICs entered the consumer market at very reasonable prices.
About Indesign, LLC
Today you can find dual-frequency GPS in a growing number of tablets, smartphones, and other consumer devices that will continue to drive the cost lower and the functionality up. Indesign recently tested one of these new receivers and got repeatability and accuracy in the range of a few centimeters (with a little help from another technology called RTK, a topic for another blog). Expect to see a wave of new devices that take advantage of this amazing 10-100X improvement in performance over today’s technology.
Indesign, LLC is a multi-discipline engineering design firm that provides full turnkey electronic product development to allow clients to get their new product ideas into the market quickly. Indesign offers complete product development capabilities, starting with a product concept and finishing with a ready-to-manufacture design. If you need help with a GPS-related project, please contact us at (317) 377-5450 today!