High Resolution Millimeter Wave SAR for Moving Target Indication

Inhalt:
Synthetic aperture radar (SAR) is an imaging radar technique that provides mapping of static ground scenes. Some existing and forthcoming SAR systems thereby provide very high resolution in the centimeter domain. While high azimuth resolution is achieved by signal processing techniques, range resolution for a traditional frequency modulated system is solely dependent on the signal bandwidth. For millimeter wave (mmW) SAR, operating at frequencies roughly between 30 and 100 GHz, a signal bandwidth of several hundred megahertz or even in the range of gigahertz is achievable. While mmW SAR is generally well suited for ground moving target indication (GMTI), especially at very slow radial target speeds, higher speeds may cause effects that not only displace moving targets but smear and defocus them considerably if not letting them disappear at all. This makes it difficult for GMTI algorithms to detect such targets. Additionally, smearing and defocus are more severe and disturbing at higher resolutions. We analyze the conditions where mmW SAR GMTI works fine and show simulated and real examples of moving targets at 35 GHz and compare them to L-band SAR data.