Instantaneous ultra-wideband sensing using frequency-domain channelization
View Patent ↗A radar system wherein a radar return is channelized by frequency into a plurality of channels, and each of the channels is sampled by a respective analog-to-digital converter that has a sampling rate less than the Nyquist rate of the radar return. The digitally sampled channel signals are Fourier transformed into the frequency domain, where each of the frequency-domain channel signals is matched-filtered according to a respective partial matched filter. The channel signals are then transformed back to the time domain, whereupon they are added together to generate the impulse response of the radar system responsive to the radar return.
1. A method, comprising:
responsive to receipt of a radar return from a scene, the radar return having a bandwidth comprising a plurality of frequencies, outputting a first channel signal and a second channel signal, the first channel signal representative of the radar return for first frequencies in the frequencies, the second channel signal representative of the signal for second frequencies in the frequencies, the first frequencies including at least some of the second frequencies;
applying a first partial matched filter to the first channel signal;
applying a second partial matched filter to the second channel signal; and
outputting a response signal based upon the matched-filtered first channel signal and the matched-filtered second channel signal, the response signal indicative of a target in the scene.
2. The method of claim 1 , wherein the first partial matched filter is based upon the first frequencies and the second partial matched filter is based upon the second frequencies.
3. The method of claim 1 , wherein the radar return comprises an echo of a radar signal transmitted toward the scene.
4. The method of claim 3 , further comprising prior to the radar signal being transmitted toward the scene, computing a calibrated matched filter based upon a test signal, wherein the test signal is the same signal as the radar signal.
5. The method of claim 4 , wherein the first partial matched filter and the second partial matched filter are based upon the calibrated matched filter.
6. The method of claim 1 , the first partial matched filter and the second partial matched filter based upon a complete matched filter defined over the bandwidth.
7. The method of claim 6 , the first partial matched filter taking first values for the first frequencies and taking zeros for all other frequencies in the bandwidth.
8. The method of claim 7 , the second partial matched filter taking second values for the second frequencies and taking zeros for all other frequencies in the bandwidth.
9. The method of claim 1 , wherein the first channel signal and the second channel signal are output by way of a first bandpass filter and a second bandpass filter, respectively.
10. The method of claim 1 , further comprising:
prior to applying the first partial matched filter to the first channel signal, digitally sampling the first channel signal by way of a first analog-to-digital converter (ADC); and
prior to applying the second partial matched filter to the second channel signal, digitally sampling the second channel signal by way of a second ADC.
11. The method of claim 10 , wherein the first ADC and the second ADC have respective sampling rates that are less than twice the bandwidth of the radar return.
12. A signal processing system configured to perform acts comprising:
responsive to receipt of an input signal having a bandwidth, outputting a first channel signal and a second channel signal, the first channel signal representative of the signal for first frequencies in the bandwidth, the second channel signal representative of the signal for second frequencies in the bandwidth, the first frequencies including at least some of the second frequencies;
generating a first discrete-time channel signal by sampling the first channel signal at a first rate that is less than twice the bandwidth of the input signal;
generating a second discrete-time channel signal by sampling the second channel signal at a second rate that is less than twice the bandwidth of the input signal; and
outputting a response signal based upon the first discrete-time channel signal and the second discrete-time channel signal.
13. The signal processing system of claim 12 , wherein outputting the response signal is based upon applying a first partial matched filter to the first discrete-time channel signal and applying a second partial matched filter to the second discrete-time channel signal.
14. The signal processing system of claim 13 , wherein the first partial matched filter is based upon the first frequencies and the second partial matched filter is based upon the second frequencies.
15. The signal processing system of claim 13 , the first partial matched filter and the second partial matched filter based upon a complete matched filter defined over the bandwidth.
16. The signal processing system of claim 15 , the first partial matched filter taking first values for the first frequencies and taking zeros for all other frequencies in the bandwidth.
17. The signal processing system of claim 16 , the second partial matched filter taking second values for the second frequencies and taking zeros for all other frequencies in the bandwidth.
18. The signal processing system of claim 12 , wherein the input signal is a radar return.
19. The signal processing system of claim 12 , wherein the first channel signal is output by way of a first filter configured to pass the first frequencies and the second channel signal is output by way of a second filter configured to pass the second frequencies.
20. A system comprising:
a radar transmitter that emits a radar signal toward a scene; and
a radar receiver that receives a return echo of the radar signal emitted by the trader transmitter, the radar receiver configured to perform the following acts:
responsive to receipt of an input signal having a bandwidth, outputting a first channel signal and a second channel signal, the first channel signal representative of the signal for first frequencies in the bandwidth, the second channel signal representative of the signal for second frequencies in the bandwidth, the first frequencies including at least some of the second frequencies;
generating a first discrete-time channel signal by sampling the first channel signal at a first rate that is less than twice the bandwidth of the input signal;
generating a second discrete-time channel signal by sampling the second channel signal at a second rate that is less than twice the bandwidth of the input signal; and
outputting a response signal based upon applying a first partial matched filter to the first discrete-time channel signal and applying a second partial matched filter to the second discrete-time channel signal, the response signal indicative of a target in the scene.