Synthetic Aperture Positioning Using Subaperture Interference

The passive positioning algorithm based on synthetic aperture technology is affected by residual frequency offset (RFO), which leads to inaccurate azimuth Doppler signals and greatly affects the positioning results. In response to this issue, this article proposes a synthetic aperture positioning (SAP) method using subaperture interference (SI). By dividing the received signal into two subapertures of equal duration and through the Doppler signal phase interference, a fixed frequency offset is transformed into a fixed phase offset. Also, the original Doppler signal is transformed into a Doppler difference signal. Thus, high-precision positioning results can be obtained through SAP. The proposed method is specifically explained in the article, and we derived the best selection of data period and division of subaperture that optimize the algorithm performance. The simulation results and experimental data are included to show the performance of the proposed method and compared to the frequency difference of arrival (FDOA).