Polynomial Fitting Emitter Localization Method Based on Multisubaperture Phase Stitching

In passive localization, the synthetic aperture positioning (SAP) method enables high-precision positioning under low signal-to-noise ratio (SNR) conditions. However, higher order phase errors induced by platform self-localization errors degrade image focusing and reduce localization accuracy. In this letter, a polynomial fitting approach based on designing optimal prewhitening filters using autoregressive (AR) models and employing iteratively reweighted least squares (IRLS) is applied to the unwrapped phase to eliminate higher order error components. In addition, a multiple subaperture phase stitching method is proposed to mitigate phase susceptibility to noise interference and error accumulation during phase unwrapping. The effectiveness of the proposed method is validated through both simulations and UAV experiments. Results demonstrate that meter-level localization accuracy can be achieved for the emitter target.