Abstract: A frequency jitter compensation radar system which frequency modulates a transmitter laser beam with simultaneously generated up- and down-chirped frequency modulated signals. The frequency modulated transmitter beam is used to scan a target and a reflected light beam is received for each pixel location of a radar system. The reflected light beam is heterodyned with a local oscillator laser beam and upon detection two separate electrical signal channels are provided representing tb up- and down-chirped frequency modulated signals. These up- and down-chirped signal channels are compressed and are further processed as the return signals of a radar system as by averaging the peak detection measurement from the two channels for each pixel to provide frequency jitter compensation commonly resulting from speckle from a target. Electro-optic or acoustic-optic arrangements may be used to frequency modulate the transmitter laser beam.
Abstract: A fuzzy controller (130) for use in target detection systems. The fuzzy controller (130) includes a first circuit (132) for determining a number of false alarms in a frame of data. A second circuit (136) determines a desired number of false alarms for the frame of data. A third circuit (134-152) computes a threshold multiplier factor based on the number of false alarms, the desired number of false alarms, and one or more fuzzy rules. In a specific embodiment, the first circuit (132) includes a target detection system for providing addresses of pixels whose values are within a predetermined range relative to a detection threshold. The second circuit (136) includes an input device (136) for accepting the desired number of false alarms as input to the fuzzy controller (130). The third circuit (138-152) includes a fuzzifier input calculation circuit (134) that computes a fuzzifier input value based on the number of false alarms detected in a frame and the desired number of false alarms.
Type:
Grant
Filed:
February 26, 2001
Date of Patent:
February 25, 2003
Assignee:
Raytheon Company
Inventors:
Todd L. Baker, Timothy E. Caber, Hien T. Dang, Thomas K. Lo, Sheldon S. Wald