Null Filter Mobile Radar (NFMRAD): Concept Verification

摘要

The Null Filter Mobile Radar (NFMRAD) concept is described, and the need for narrow-band digital filters that can distinguish between positive and negative frequencies is explained. Two different procedures for realizing complex bandpass and bandstop filters of the infinite impulse response type are described, and their properties evaluated. A procedure for generating complex bandpass and bandstop filters fo the finite impulse response type is also described, and the particular applicability of these filters to NFMRAD is discussed. The experimental NFMRAD system is described, and the field installation and test program is explained. A ground based experiment using a truck traveling at about 30 mph (13.4 m/s) as the radar platform is described. Under these experimental conditions, the performance of NFMRAD is computed theoretically and compared to expected performance of systems using Chebyshev and uniform-fed antenna arrays with and without filters. Real-time processing tasks such as antenna pattern synthesis, Doppler filtering, and detection processing are described. Hardware performance and a functional description of the radar hardware is presented. NFMRAD transmitter, receiver, and digital processing specification are reviewed, and experimental system restrictions are made clear. The NFMRAD system is found to have its greatest superiority over other systems for cases in which the differences between the radial velocities of the target and the local clutter is not large. (Author)