Design and integration of a low cost, size, weight, and power vertical-pointing synthetic aperture radar

Abstract

In modern radar applications, cost, size, weight, and power (C-SWaP) are increasingly becoming critical factors in the design process. For use cases specifically in airborne radio frequency (RF) imaging, there is a key opportunity for improvement in C-SWaP. Typical synthetic aperture radar (SAR) systems consist of aircraft-mounted electronics utilizing an inertial measurement unit (IMU) to provide accurate and precise location information in order to form the synthetic aperture as the aircraft is in flight. Most current SAR applications do not have strict requirements for SWaP since an airframe is capable of handling a sizable amount of weight. With the increased proliferation of smaller airborne vehicles and drones, there is a demand for low C-SWaP radar systems capable of imaging. In this work, the design and operation of a radar system is discussed. First, basic system requirements including a basic link-budget analysis, and system architecture with low C-SWaP are explored. The analog hardware is then discussed and a RF chain analysis is conducted. The capabilities of the backend module used to capture the data and the IMU used to obtain positional information are then briefly discussed. A basic analysis of the signal processing for SAR is conducted. Finally, results of airborne SAR imaging conducted utilizing the radar system described above are discussed. The system is used in a vertical-SAR (VSAR) configuration as a radar-altimeter to produce an elevation profile of the ground covered by the aircraft.