Estimation of errors in INS with multiple GPS antennas

This paper presents a technique to estimate strapdown INS errors with a multi-antenna GPS receiver. A GPS measurement system is introduced in which a compromise between accuracy and computational load is achieved. The combination of differential pseudo-range measurement of vehicle position and differential carrier phase measurements of relative positions among antennas could be considered as a practical scheme for INS error correction. It is shown that position measurements from at least three GPS antennas are sufficient for the estimation of INS errors in time-invariant models. Additional velocity measurements do not change the unobservable subspace of the error models. Numerical simulation results are given to show the effectiveness of the proposed measurement scheme on the estimation of vehicle attitude and biases of low-cost IMU