Indoor Operations by FMCW Millimeter Wave SAR Onboard Small UAS: A Simulation Approach

Abstract

A dedicated system simulator is presented in this paper for indoor operations onboard small Unmanned Aerial Systems (UAS) by a novel millimeter wave radar sensor. The sensor relies on the principle of Synthetic Aperture Radar (SAR) applied to a Frequency Modulated Continuous Wave (FMCW) radar system. Input to the simulator are both design parameters for Synthetic Aperture Radar (SAR), which should be able to cope with the stringent requirements set by indoor operations, and information about platform navigation and observed scene. The scene generation task is described in detail. This is based on models for point target response on either a completely absorbing background or fluctuating background and ray tracing (RT) techniques. Results obtained from scene processing are finally discussed, giving further insights on expected results from high-resolution observation of an assigned control volume by this novel SAR sensor.

2D Frequency Domain Fully Focused SAR Processing for High PRF Radar Altimeters

“…Across-track compression is achieved on ground by a Fourier transform. It is noteworthy, however, that in some cases deramping has been implemented also for SAR, as in the frequency modulated continuous wave (FMCW) SAR [18]. Likewise, the future Poseidon-4 altimeter instrument will be based on an on-board matched filter.…”

“…is safely ignored in SAR systems, since it is almost a constant throughout the whole data block. An explicit expression of the integral in Equation (5) for the altimeter case is then (use also Equation (18) in Reference [15]):…”

“…Since the transponder acts like a point target with high power with respect to the noise and surrounding clutter, it allows to verify the effectiveness of the focusing algorithm with in-orbit data by inspection of the characteristics of the focused IRF. To perform this analysis, we used ESA CryoSat Full Bit Rate (FBR) Baseline-C data and we applied calibration corrections according to Reference [18]. The following results were obtained processing the pass over the Svalbard transponder that was acquired by CryoSat on 21 August 2012 around 22:42 UTC time.…”