System and method for fast frequency hopping waveforms with continuous phase modulation in radar systems

Abstract

A radar system that uses fast frequency hopping transmit waveform and filter bank receiver consisting of both analog and digital components. The waveform steps discrete frequency tones with short duration and modulates a continuous phase signal on each tone. The frequency hopping patterns are generated using pseudo-random permutation or low-collision method of anti-causal code shifting. To process waveform at radar receiver, a filter bank is used with squelching switches and controls to reduce distortion from strong signal into the receiver. Using the Strong Return Estimator, the timing of the strong signal is used to control the squelching switches.

1 . A radar system comprising:
 a plurality of transmitters configured to transmit radio signals;   a plurality of receivers configured to receive radio signals that include radio signals transmitted by the transmitters and reflected from objects in an environment;   wherein at least one of the transmitters of the plurality of transmitters is configured to generate a fast frequency hopping waveform that uses coded hopping patterns to achieve frequency diversity; and   wherein the at least one transmitter comprises a step frequency generator and a phase modulator configured to use continuous phase modulation to minimize amplifier nonlinearities in a transmission waveform.   
     
     
         2 . The radar system of  claim 1 , wherein at least one of the receivers of the plurality of receivers comprises a filter bank comprising analog and digital components, wherein the filter bank comprises an analog section having squelch switched inserted in each sub-band receiver. 
     
     
         3 . The radar system of  claim 2  further comprising a strong return estimator configured to estimate a return delay of strong signals from either signal reflections or power coupling from ones of the transmitters to ones of the receivers, wherein a strong signal is a signal with a signal strength above a threshold, and wherein such signals interfere with other signals. 
     
     
         4 . A method for generating a low-collision code pattern in a radar system, the method comprising:
 transmitting, with a plurality of transmitters, radio signals;   receiving, with a plurality of receivers, radio signals that include radio signals transmitted by the transmitters and reflected from objects in an environment;   generating a fast frequency hopping waveform that uses coded hopping patterns to achieve frequency diversity;   wherein generating the fast frequency hopping waveform comprises the use of anti-causal shifting and pattern comparisons.   
     
     
         5 . The method of  claim 4 , wherein the generation of the fast frequency hopping waveform comprises continuous phase modulation to minimize amplifier nonlinearities in a transmission waveform, wherein at least one of the transmitters comprises a step frequency generator and a phase modulator configured for continuous phase modulation. 
     
     
         6 . The method of  claim 4 , wherein at least one of the receivers of the plurality of receivers comprises a filter bank comprising analog and digital components, wherein the filter bank comprises an analog section having squelch switched inserted in each sub-band receiver. 
     
     
         7 . The method of  claim 4  further comprising estimating, with a strong return estimator, a return delay of strong signals from either signal reflections or power coupling from ones of the transmitters to ones of the receivers, wherein a strong signal is a signal with a signal strength above a threshold, and wherein such signals interfere with other signals.