Gaussian Approximations for Intra- and Intersystem Interference in RNSS

Spread spectrum multiple access is widely used by radionavigation satellite services to separate an increasing number of systems, satellites, and signals within a common frequency band, but multiple access interference (MAI) needs to be carefully modeled and monitored for spectrum coordination or performance analysis of safety-critical services. Within the class of Gaussian approximations for MAI, we derive the very accurate conditional Gaussian approximation, being the first to consider a delay/Doppler channel, non-uniform symbol rates, and arbitrary improper signaling.