Adaptive Array Processing for GPS Interference Rejection

One area of active interest in the GNSS community is determining the vulnerability of multi-antenna signal processing algorithms given calibration errors in antennas and analog front-end hardware. Errors introduced by the antennas or by the analog hardware that are not completely mitigated by software or calibration may lead to degradation in steering-vector accuracy. Of interest are the characterization and mitigation of any consequent reduction in C/N0 and biasing of code and carrier phase estimates. When a reference signal is available (as is the case for GPS) and when there may be degradation in steering-vector accuracy (due to hardware errors), then an adaptive mean-square-error based approach may have significant C/N0 advantages. Further, exercising both spatial and temporal degrees of freedom is desirable in maximizing C/N0 for adaptive antenna arrays. Stanford University’s multi-channel hardware testbed demonstrates the feasibility of implementing adaptive array processing for GPS signals in real time.