Commanding, controlling, and maintaining the health of satellites requires a clear operating spectrum for communications. Electro Magnetic Interference (EMI) from nearby satellites can interfere with these communications. The very first step to mitigate these EMI effects is to geolocate them. This SBIR topic seeks to develop methods and system concepts that provide enhanced reference emitters to satellite geolocation units that otherwise are unable to geolocate potential EMI sources at Low Earth Orbit (LEO) and/or Geostationary Orbit (GEO) distances in real time. In this proposal, we propose a solution called "RACE"ÂÂ to geolocate space-based EMI sources. The RACE has two working modes: Radar mode and Communication mode. In Radar mode, the reference transmitter or emitter will search the nearby zone of the reference satellite (whose geolocation can be accessed by the reference emitter system) and detect the beam angle. In communication mode, two designed ranging codes will be transmitted in two narrow beams: one for the EMI source and the other for the reference satellite, respectively. Since the reflected signals are relatively weak, we propose adaptive ranging chip rate, and direct sequence spread spectrum (DSSS) to maintain the ranging communication under lower signal-to-noise ratio (SNR) conditions.
