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

Abstract

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. INDEX TERMS Angle of arrival, bias compensation, passive localization, satellite, Taylor-series expansion.

Satellite-based Localization of IoT Devices using Joint Doppler and Angle-of-Arrival Estimation

“…Note that the constant term of the PDF, 1 σ √ 2π is brought out from the expression, which will then be represented as C in the following steps. Then, we substitute the exponential term from the Gaussian PDF in (11) to (b). Finally, the equation can be simplified as presented in (c).…”

Satellite-based Localization of IoT Devices using Joint Doppler and Angle-of-Arrival Estimation

“…In addition to Doppler measurements, angle-of-arrival (AoA) was one of first methods used in finding radio emitters, originally was done by mechanically steering the receiving antenna. With the advancement in digitally controlled phase shifters and in fully-digital radio heads, multi-antenna AoA estimation can now achieve very accurate results [9]- [11] especially with the use of super-resolution methods such as the MUSIC [12], ESPRIT [13], and weighted subspace fitting [14], [15]. AoA does not require clock synchronization with the transmitter, thus making it simpler to implement [10] than the time-of-arrival (ToA) method used in GNSS.…”

“…Also, it is crucial to consider the geolocation bias in the target position estimate due to high non-linearity in the AoA measurements [24]. To account for the bias error, several compensation methods have been presented in [11], [25], [26]. For example, a reduced-bias pseudolinear estimator in [26] can decrease the bias by acquiring sufficient measurements where the bias is dependent on the correlation vector of the measurement matrix.…”

“…For example, a reduced-bias pseudolinear estimator in [26] can decrease the bias by acquiring sufficient measurements where the bias is dependent on the correlation vector of the measurement matrix. Moreover, both works in [11] and [25] apply a Taylor-series expansion to estimate the bias; where [11] applies it directly to the target position estimate, [25] applies it to the maximum likelihood (ML) cost function up to the second order.…”

Use of Doppler and Doppler Rate for RF Geolocation Using a Single LEO Satellite

“…Current SSG solutions generally involve either an angle-of-arrival (AoA) or a Doppler-based approach. AoA-based algorithms [4]- [7] offer simple solutions but are limited to relatively high signal strength scenarios,…”