A Low-power, Real-time, S-band Radar Imaging System

A real-time S-band radar imaging system will be shown in this paper that uses a spatially diverse antenna array connected to a highly sensitive linear FM radar system and uses a synthetic aperture radar (SAR) imaging algorithm to produce real-time radar imagery. The core of this radar system is a high-sensitivity, range gated, radar architecture. Previous work has demonstrated the effectiveness of this radar architecture for applications requiring low-power and high sensitivity for imaging through lossy dielectric slabs at S-band and in free space at both S and X bands. From these results it was decided to develop a real-time S-band SAR imaging system. This is achieved by constructing a spatially diverse antenna array that plugs directly into a pair of S-band transmit and receive radar front ends; thereby providing the ability for real-time SAR imaging of objects. The radar system chirps from approximately 2 GHz to 4 GHz at various rates from 700 microseconds to 10 milliseconds. Transmit power is adjustable from approximately 1 milliwatt or less. The image update rate is approximately one image every 1.9 seconds when operating at a chirp rate of 2.5 milliseconds. This system is capable of producing imagery of target scenes made up of objects as small as 1.25 inch tall nails in free space without the use of coherent integration. Previous applications for this radar system include imaging through dielectric slabs. It will be shown in this paper that this radar system could also be useful for real-time radar imaging of low RCS targets at S-band.