GPS Systems in Trucks
Kathy Fehr 9th
GPS History
GPS navigation has been around for more than a decade. Twenty years ago, road trip meant pulling out a bunch of fold out maps stuffed into your pocket. Along the way those maps gave way MapQuest or Yahoo Maps print-outs, and now fortunately we have portable navigation device and GPS-enable smartphones.
The Origin
The U.S. Department of Defense first developed satellite-based global positioning technology for the military. An early satellite-based system dubbed TRANSMIT was up and running as early as 1960, with more refined and prices versions involving multiple satellites in general military use by the early 1980s. But it wasn't until 2000 that precision GPS navigation became open to the public.
The Road to In-Car Navigation
Even after 2000, it would be a while before consumers would see GPS navigation in cars. Fortunately, the dot com boom was already coming to the rescue. Map-based websites weren't perfect, though. Early routing algorithms were imprecise, and sometimes repeated steps over and over again-long lists of instructions that basically said to stay on the same road for 12 miles were a constant source of frustration. Plus, you still had to print them out and take them with you , which meant you needed to pull over to read the next few steps. But now that we have the GPS navigation in our vehicles it's not even half the amount of trouble.
Sources
Reflection
Reflected GPS signals were first proposed as a remote sensing tool by Martin-Neira in 1993. Most of the early studies of GPS reflections were developed for aircraft or platforms. In those experiments, the receiver/antenna systems were optimized to receive the reflected signals.