Pseudo-Measurements as Aiding to INS during GPS Outages

The complementary nature of INS and GPS navigation systems can be used advantageously in navigation systems design, as long as GPS measurements are available. However, when GPS measurements become unavailable (e.g., in urban environments or during jamming), the INS navigation solution will drift with time due to inherent bias. We propose fusing pseudo-measurements with INS as a means to circumvent this problem. This is carried out using knowledge of the platform behavior, and translation of the operating environment's features into pseudo-measurement aiding for the estimation process. Field experiments show significant improvement in the accuracy of the estimated vehicle states.