Bias Compensation for AOA-Geolocation of Known Altitude Target Using Single Satellite

To reduce the passive localization bias caused by the nonlinearity between the target position and measurements under high noise level and poor geometry conditions, the bias compensation method for known altitude target geolocation using angles of arrival (AOA) obtained by a single satellite is proposed. The basic idea of this method is to estimate the bias first, and then subtract it from the estimation of the target position. Different from existing bias estimate methods which perform Taylor-series expansion on the maximum likelihood (ML) cost function, the proposed method directly applies Taylor-series expansion on the closed-form target location estimate. Interestingly, the expectations of the odd-order expansion terms of the Taylor-series in the proposed method are equal to zero, which indicates that higher bias estimation accuracy can be achieved with the same order of expansion compared with the existing methods. Furthermore, the theoretical analysis is performed and the result indicates that the Euclidean norm of the bias is independent of the azimuth angle and is positively correlated with the elevation angle. Finally, the computer simulations verify the superior performance of the proposed method and the theoretical analysis.