Adaptive OFDM subcarrier design for SAR Cross-Range Profile Reconstruction

Abstract

In this paper, we investigate an adaptive Orthogonal Frequency Division Multiplexing (OFDM) subcarrier design for a Synthetic Aperture Radar (SAR) system that can be used in Through-the-Wall radar Imaging (TWI), detection of hidden object and pipelines inspection. At first, an OFDM SAR model is developed for a single target detection. The target is reconstructed via match filtering of the estimated phase history with a reference function. The phase history is estimated using Least Square Estimate (LSE) and parameters such as Root Mean Square Error (RMSE), cumulative side lobe levels and the main lobe width are used to test and compare the accuracy of the reconstruction process. Simulation results shows that increasing the number of subcarriers results in an improvement in the target reconstruction but at the cost of having a wider main lobe. The results are also compared with the Single Frequency (SF) case. Initial results shows that OFDM SAR method is a promising technique in SAR reconstruction process as compared with SF case such as Frequency Modulated Continuous Wave (FMCW). The technique is later extended to the detection of multiple targets scene.