Ultrawideband Single-Pass Interferometric SAR Integrated with Multi-Rotor UAV

Ultrawideband (UWB) Interferometric Synthetic Aperture Radar (InSAR) integrated with multi-rotor Uncrewed Aerial Vehicle (UAV), or UIMU in this work for brevity, provides ultrafine-resolution, all-weather, 3D surface imagery at any time of day. UIMU can be rapidly deployable and low-cost, and therefore a critical new tool for low-altitude remote sensing applications, such as disaster response, environmental monitoring, and intelligence surveillance and reconnaissance (ISR). Traditional repeat-pass data collection methods reduce the phase coherence required for InSAR processing of ultrafine-resolution datasets due to the unstable flight behavior of multi-rotor UAVs. Collecting Synthetic Aperture Radar (SAR) datasets using two receive channels during a single-pass will improve phase coherence and the ability to produce ultrafine-resolution 3D InSAR imagery.

This work proposes to quantify and characterize 3D target-position accuracy for a dual-channel 6 GHz bandwidth (2 cm range resolution) frequency modulated continuous wave (FMCW) radar integrated with the Aurela X6 hexacopter to establish novel single-pass UWB InSAR data collection methods and processing algorithms for multi-rotor UAV. The feasibility of the proposed investigation is demonstrated by the preliminary qualitative analysis of single-pass InSAR imagery presented in this proposal. Fieldwork will be conducted to measure the positions of GPS located corner reflectors using the UIMU system. Algorithms for motion tolerant Time-Domain Backprojection (TDBP), InSAR coregistration, and digital elevation mapping novel to multi-rotor UAV at UWB will be developed and presented. An analysis of vehicle motion induced phase decoherence, and InSAR imagery signal to noise ratio (SNR) will be presented. The TDBP SNR performance will be compared to the Open Polar Radar Omega-K algorithm to attempt to quantify motion tolerance between the different SAR processing algorithms.

This work will establish a foundation for future investigations of real-time image processing, separated transmission and receive platforms (bistatic), or swarm configurations for UIMU systems.