Compact super high-resolution Ku-band multi-rotor UAV SAR system

Abstract

Synthetic Aperture Radar (SAR) can provide high-resolution, day-and-night and weather-independent ground images. Conventional space borne and airborne SAR systems are bulky and expensive.

A light-weight and low cost Ku-band SAR system was previously developed by students and researchers from NTU EEE. To enhance SAR resolution and reduce system weight and size further, a Ka-band SAR system was also designed and developed. Comparisons will be made to determine which is the more efficient system before more tests are carried out.

The Ku-band SAR system employs a 1.2 GHz bandwidth linear Frequency Modulation Continuous Wave (FMCW) waveform and 16 GHz, resulting in a resolution of 0.125m. An AD9914 evaluation board is used to generate a 600MHz bandwidth FMCW and 900MHz center frequency FMCW signal.

The Ka-band SAR system employs a 1.8 GHz bandwidth linear Frequency Modulation Continuous Wave (FMCW) waveform and 36.6 GHz carrier. This allows the system to have a range resolution of 0.08333m. An ADF4159 evaluation board is used to generate a 600MHz bandwidth FMCW and 12.2 GHz center frequency FMCW signal as the initial waveform.

Beat signals from both systems are sampled and recorded with an ADC card. The system is implemented and a series tests are conducted. While indoor tests have already been conducted, more tests are conducted under varying circumstances to try to optimize the system for future outdoor trials.