Abstract: A system and method for passively estimating range and angle of a source are disclosed. The source may be any wave source including radio-frequency (RF), optical, acoustic or seismic sources. In some RF embodiments, the system includes a single aperture antenna to simultaneously receive RF signals from the RF source through a plurality of sub-apertures, and a signal processor to perform a proximity test using samples simultaneously collected from the sub-apertures to determine whether or not to calculate angle and range estimates to the source based on either a curved wavefront assumption or a planar wavefront assumption.

Abstract: A system and method for passively estimating range and angle of a source are disclosed. The source may be any wave source including radio-frequency (RF), optical, acoustic or seismic sources. In some RF embodiments, the system includes a single aperture antenna to simultaneously receive RF signals from the RF source through a plurality of sub-apertures, and a signal processor to perform a proximity test using samples simultaneously collected from the sub-apertures to determine whether or not to calculate angle and range estimates to the source based on either a curved wavefront assumption or a planar wavefront assumption.

Abstract: An efficient receiver system (80) adapted for use with a pulsed radar system. The receiver system (80) includes a first circuit (82) for receiving a first signal and providing a second signal in response thereto. A second circuit (96) compares the second signal to a predetermined sequence (98) and provides a compare signal in response thereto. A third circuit (104) stores information pertaining to the second signal in response to the compare signal. A fourth circuit (92) generates receiver system instructions based on the stored information. In a specific embodiment, the second signal is a digital signal and the sequence is a digital sequence. The pulsed radar system includes a circuit for receiving and collecting data during a first dwell and for processing the data during a subsequent dwell. An inter-dwell time interval exists between the first dwell and the second dwell. The first, second, third, and/or fourth circuits (82, 96, 104, and/or 92) operate during the inter-dwell period.

Abstract: A technique for operating a communication link in RF proximity to an operational radar. A data link waveform is employed which allows a data link receiver to detect an alert indication during normal radar operation. When the alert is detected, the system briefly inhibits radar operation to receive the information content of the data link message. A data link message rate is selected to keep the impact to radar operation at a minimum.

Abstract: A system (10) for reducing range sidelobes adapted for use with pulsed radar systems. The inventive system (10) includes a mismatched filter (90) for correlating a received signal (84) with a correlator signal (92) having a different length than the transmit signal (84) and for providing a predetermined number of reduced range sidelobes (97) at the output of the mismatched filter (90). The mismatched filter (90) has a first locally optimum sequence that is the correlator signal (92). The mismatched filter (90) has an input device (86) for receiving an extended locally optimum sequence (84) that is a received signal (84). The first locally optimum sequence (92) is a sub-sequence of the extended locally optimum sequence (84). In a specific embodiment the mismatched filter (90) has a Barker-based code that is the correlator signal (92). The mismatched filter (90) has an input device (86) for receiving an extended Barker-based code that is a received signal (84).

Abstract: A radar tracking system 100 adapted for use with existing radar tracking systems. The inventive system includes a radar target detection system 106, 108 for detecting radar targets in clutter using magnitude and angular position information obtained from return signals. A tracking algorithm 104 is used to track and update the positions of said targets with respect to the position of the radar system. The tracking algorithm includes a true target angle estimator 110 for maintaining accurate target angle information when the target is clutter and when the target is out of clutter. The tracking algorithm maintains accurate target distance information when the target is in clutter and when the target is out of clutter. In a specific embodiment, accurate distance information is maintained in a track file 122 where the amplitudes of return signals are stored once a target is detected by the detection system 100.

Abstract: A radar system includes a radar receiver that provides the amplitude and the angular position of a plurality of return signals. A computer forms a test function of amplitudes and angular positions of the plurality of return signals and compares the test function with a threshold value. Returns associated with a test function whose value is equal to or greater than the threshold value are determined to be targets, and those with lesser values are considered clutter.