Software-defined Radio GNSS Receiver Signal Tracking Methods

Abstract

Software-defined radio (SDR) - based GNSS receivers are flexible. SDR technology allows changing processing algorithms and adding new signals without any hardware modifications. The main drawback of such a receiver is high computation load. Signal tracking module takes most part of CPU time. This paper considers distributed receiver architectures where most of the processing is performed in a remote PC or a server. The amount of raw data in the SDR receiver is too large for complete transfer. Two methods of reduction are discussed: truncating epochs and disabling tracking for a certain period. The limitations of each method are estimated using simulations. Epochs can be truncated by 50-75% depending on signal-to-noise ratio. The maximum disabling time is about 0.5s for a stationary receiver and 0.1s for a car receiver. Using both methods in combination reduce data volume by 95.4% for a stationary receiver and 83.3% for a car receiver.