Short-Time Coherent--Incoherent Synthetic Aperture Radar Processing for a Handheld Imaging System

This article presents a processing technique that mitigates the impact of positioning errors on the quality of the images retrieved using handheld (or portable) scanners based on synthetic aperture radar (SAR). These systems rely on the use of tracking systems to combine the information acquired at multiple positions to achieve high-resolution images. This is especially challenging at millimeter-wave (mmWave) frequencies in the absence of high-accuracy tracking systems external to the handheld scanner. To this end, the proposed technique employs a hybrid coherent-incoherent SAR processing method especially suited for mitigating the impact of positioning errors from tracking systems performing simultaneous localization and mapping (SLAM). The proposed technique was experimentally validated using a handheld scanner comprising a compact radar module and a tracking camera that performs SLAM. Results show that if fully coherent processing is used, the quality of the obtained images is greatly degraded, and if fully incoherent processing is considered, there is a significant resolution loss, which prevents accurately imaging the shape of the targets. In contrast, using the presented method, it is possible to successfully image the targets, mitigating the impact of positioning errors from the tracking camera.