The regression equations show that even though selective availability
was turned off on May 1, 2000, elevations measured with the GPS had large errors and were not consistent.
IEC's classified system incorporates three functions, which include selective availability
, anti-spoofing and the associated cryptograph, all which are required under the Global Positioning System Precise Positioning Service (PPS) requirements.
Among the space and information-warfare (IW) programs highlighted are computer network defense (CND) and CND operations (a total of $156 million), IW operations and classified programs ($746 million), GPS navigation warfare ($17 million), and GPS Selective Availability
Anti-Spoofing Modules ($18 million).
The IEC receivers--based on a selective availability
anti-spoofing module--can withstand the 15,000g acceleration firing from a gun.
However, the GPS signal is inherently noisy due to the selective availability
coding on the signal.
The low-cost hardware upgrade translates to a more reliable operation and additional capacity, providing support for future upgrades, such as Selective Availability
Anti-Spoofing Module (Saasm) testing.
This strategy, called selective availability
, reduces the accuracy of civilian and unauthorized users to 100 meters 90 percent of the time -- enough for navigation but inadequate for weapons delivery.
The most significant short-term error source is selective availability
IEC's line already includes a number of GPS products, and the acquisition of Alliant's Selective Availability
Anti-Spoofing Module (SASSM) GPS receivers will serve to bolster IEC's position in the GPS market.
Among these technologies are development of software tools and compilers, mandatory use of Ada, selective availability
of global positioning systems, environmental protection research in Air Force laboratories and aircraft cockpit design (dependence on aircraft manufacturers is recommended).