Characterization of global positioning system earth surface multipath and cross correlation for aircraft precision approach operations using software radio technology.

摘要

A GPS Software Defined Radio (SDR) is designed for the analysis of GPS error sources, and is applied to evaluate earth-surface multipath errors and self-interference errors due to C/A code cross correlation for aircraft precision approach operations.; The pseudorange error caused by earth-surface multipath is characterized for airborne GPS receivers. A detection algorithm that can estimate the strength of earth-surface multipath from the received signals is developed and implemented in the GPS SDR. The response to earth-surface multipath from different GPS receiver architectures is studied, from which it is determined that the pseudorange errors could be bounded to within a few decimeters with a careful selection of tracking algorithms.; GPS self-interference caused by C/A code cross correlation is evaluated in the operational environment. The induced errors on pseudorange and Carrier to Noise Ratio estimation are characterized, and bounds are determined for relative signal strength, Doppler frequency, and Doppler change rate to limit the pseudorange errors to 0.2 m.