The ATSB^® Spaceborne GPS Receiver is a spacecraft orbit determination and timing subsystem designed for cost-effective LEO applications. It provides GPS standard time, position, and velocity measurements in a compact and low power unit at low cost. The Spaceborne GPS Receiver is supplied with "out-of-the-box" firmware suitable for its intended application in space.

The Global Positioning System (GPS) employs a constellation of 24 operational satellites, 4 in each six orbital plane, inclined at 55° with respect to Earth's equatorial. The satellites have an average altitude of 20,200 kilometers and complete one orbit in approximately 11 hours 56 minutes. The orbits are chosen so that there will always be at least four satellites that can be visible at every location.