Development of SAR transmitter for nanosatellite-based remote sensing application

Synthetic Aperture Radar (SAR) is one of radar techniques which is usually applied to improve the resolution of azimuth detection using smaller antenna size. One of its applications is for space-based remote sensing using satellite since it can get larger observation area than other SAR platforms. However, the payload of space-based SAR using satellite should satisfy some requirements in mass, power, and dimension. This paper discusses the development of SAR transmitter for nanosatellite-based remote sensing application. It is developed based on frequency modulated continuous wave (FMCW) waveform as a chirp generator which is implemented using a direct digital synthesizer (DDS) technique. Here, the use of DDS technique is to simplify the development of SAR transmitter circuit. The DDS component used in the development is an integrated circuit of AD9850 from Analog Device controlled by an ARM-based μcontroller. The chirp bandwidth FMCW waveform is 10MHz with 1 μs duration which has the range resolution of 15m.