Abstract: A method for radar signal processing separates an electric signal generated by Doppler processors of a radar into alternating current (AC) magnitudes with Doppler frequencies corresponding to absolute values between 0.1 and 4 Hz and direct current (DC) magnitudes with no Doppler frequency. An AC line and a DC line are generated, based on the AC magnitudes and the DC magnitudes, respectively, by adding respective energies across Doppler cells for each range cell and subsequently applying CFAR detector algorithm respectively. An energy level difference between an energy spike in the AC line and another energy spike in the DC line is calculated and compared with a threshold set for detecting a breathing target that is stationary. If the energy level difference is greater than the threshold, the breathing target that is stationary is detected and reported to the radar operator.

Abstract: A method of processing radar responses of a radar system characterized by a plurality of beam patterns, to determine if a given response corresponds to a reflective object. The method including, for a first beam pattern, identifying a response at an identified angle relative to a center of the first beam pattern. Then, for a second beam pattern overlapping the first beam pattern, determining if a measured response in the second beam pattern at an angle relative to the center of the second beam pattern that corresponds to the identified angle relative to the center of the first beam pattern is within a predetermined error threshold of an anticipated response calculated using the second beam pattern and the first beam pattern. If the measured response in the second beam pattern is not within the predetermined error threshold, the first response is eliminated from display and/or further tracking.

Abstract: A radar system, comprising: a receive antenna configured to receive a receive signal reflected from a bullet, the receive signal exhibiting a Doppler shift according to the motion of the bullet; and a detector implementing a set of matched filters each configured to determine a measure of correlation between the Doppler shift of the receive signal and one of a set of pre-stored Doppler shifts, wherein each of the pre-stored Doppler shifts respectively represents the Doppler shift of a bullet passing the antenna at a different speed or a distance of a point of closest approach.

Abstract: A discrete-time, digital filter for notch filtering a complex digital signal, the filter having a transfer function allowing selective filtering of complex signal components. A system for receiving a modulated signal, the system including a processor for adaptively generating filter coefficients of a discrete-time, digital filter, for filtering a complex discrete-time signal, the processor configured to (i.) identify a number of signal samples in a discrete-time signal, and use the signal samples to calculate autocorrelation values sufficient to calculate the filter coefficients, (ii.) solve a system of equations, the system of equations defined by a Toeplitz matrix and a vector to determine the coefficient values, the Toeplitz matrix defined using the autocorrelation values, and the vector defined as the autocorrelation values of a white noise signal.

Abstract: A radar system, comprising: a receive antenna configured to receive a receive signal reflected from a bullet, the receive signal exhibiting a Doppler shift according to the motion of the bullet; and a detector implementing a set of matched filters each configured to determine a measure of correlation between the Doppler shift of the receive signal and one of a set of pre-stored Doppler shifts, wherein each of the pre-stored Doppler shifts respectively represents the Doppler shift of a bullet passing the antenna at a different speed or a distance of a point of closest approach.

Abstract: A system and method for mitigating multipath propagation are disclosed herein. The method may include collecting a plurality of detections of a target, forming a plurality of models each assuming at least one parameter causing multipath propagation, determining which model best fits the detections of the target, using the best fit model to approximate the ground conditions, and using the approximated ground conditions to remove the multipath error from the observed signals.

Abstract: A system and method for mitigating multipath propagation are disclosed herein. The method may include collecting a plurality of detections of a target, forming a plurality of models each assuming at least one parameter causing multipath propagation, determining which model best fits the detections of the target, using the best fit model to approximate the ground conditions, and using the approximated ground conditions to remove the multipath error from the observed signals.

Abstract: An integrated services digital network (ISDN) private exchange device is provided, which includes connectors for connection to an ISDN local exchange, a plurality of ports for connection to respective analog telephone devices, a plurality of ports for connection to respective digital devices, and an ISDN digital port for connection to at least one additional ISDN terminal device. The private exchange device may include a pair of ports for connection to two different analog telephone devices, each having simultaneous access capability with the ISDN network. Further, the private exchange device may include four ports for connection up to four digital devices, which are each capable of simultaneously accessing the ISDN local exchange. The ISDN digital port can be connected with up to eight ISDN terminals or terminal adapters.