US-12625231-B2 - Reduced latency look-ahead for signal detector

US12625231B2US 12625231 B2US12625231 B2US 12625231B2US-12625231-B2

Abstract

Techniques are provided for reduced latency look-ahead for signal detection. An example methodology implementing the techniques according to an embodiment includes down converting a digitized signal to a first baseband signal at a first decimation rate such that the first baseband signal is provided at a first latency with a first signal to noise ratio (SNR) based on the first decimation rate. The method also includes down converting the digitized signal to a second baseband signal at a second decimation rate, greater than the first decimation rate, such that the second baseband signal is provided at a second latency with a second SNR based on the second decimation rate, the second latency greater than the first latency and the second SNR greater than the first SNR. The method continues with generating a detection threshold based on the first baseband signal prior to completion of the second baseband signal generation.

Inventors

Richard J. Lavery
Peter Ladubec, JR.

Assignees

BAE SYSTEMS INFORMATION AND ELECTRONIC SYSTEMS INTEGRATION INC.

Dates

Publication Date: 20260512
Application Date: 20231211

Claims (17)

1 . A signal detection system comprising: a first processing channel configured to down convert a digitized signal to a first baseband signal at a first decimation rate such that the first baseband signal is provided at a first latency with a first signal to noise ratio (SNR), the first latency and the first SNR based on the first decimation rate; a second processing channel configured to down convert the digitized signal to a second baseband signal at a second decimation rate such that the second baseband signal is provided at a second latency with a second SNR, the second latency and the second SNR based on the second decimation rate, wherein the second decimation rate is greater than the first decimation rate, the second latency is greater than the first latency, and the second SNR is greater than the first SNR; and a detection threshold calculator configured to generate a detection threshold based on the first baseband signal, the detection threshold generated prior to completion of the generation of the second baseband signal.
2 . The system of claim 1 , wherein the first processing channel comprises: a numerically controlled oscillator (NCO) configured to generate a down-conversion frequency signal; a mixer configured to mix the digitized signal with the down-conversion frequency signal to generate a mixed signal; a decimation circuit configured to decimate the mixed signal at the first decimation rate; and a low pass filter configured to attenuate high frequency noise from the decimated mixed signal to generate the first baseband signal.
3 . The system of claim 2 , wherein the low pass filter is an infinite impulse response filter.
4 . The system of claim 1 , wherein the second processing channel comprises: a numerically controlled oscillator (NCO) configured to generate a down-conversion frequency signal; a mixer configured to mix the digitized signal with the down-conversion frequency signal to generate a mixed signal; a decimation circuit configured to decimate the mixed signal at the second decimation rate; and a low pass filter configured to attenuate high frequency noise from the decimated mixed signal to generate the second baseband signal.
5 . The system of claim 4 , wherein the low pass filter is a finite impulse response filter.
6 . A radio frequency (RF) system-on-a-chip (SoC) comprising the signal detection system of claim 1 .
7 . A computer program product including one or more non-transitory machine-readable mediums encoded with instructions that when executed by one or more processors cause a process to be carried out for signal detection, the process comprising: down converting a digitized signal to a first baseband signal at a first decimation rate such that the first baseband signal is provided at a first latency with a first signal to noise ratio (SNR), the first latency and the first SNR based on the first decimation rate; down converting the digitized signal to a second baseband signal at a second decimation rate such that the second baseband signal is provided at a second latency with a second SNR, the second latency and the second SNR based on the second decimation rate, wherein the second decimation rate is greater than the first decimation rate, the second latency is greater than the first latency, and the second SNR is greater than the first SNR; and generating a detection threshold based on the first baseband signal, the detection threshold generated prior to completion of the generation of the second baseband signal.
8 . The computer program product of claim 7 , wherein the process further comprises: generating a down-conversion frequency signal; mixing the digitized signal with the down-conversion frequency signal to generate a mixed signal; decimating the mixed signal at the first decimation rate to generate a first decimated signal; filtering high frequency noise from the first decimated signal to generate the first baseband signal; decimating the mixed signal at the second decimation rate to generate a second decimated signal; and filtering high frequency noise from the second decimated signal to generate the second baseband signal.
9 . The computer program product of claim 7 , wherein the process further comprises attenuating, using an infinite impulse response filter, a high frequency noise from the first decimated signal, and attenuating, using a finite impulse response filter, the high frequency noise from a second decimated signal.
10 . The computer program product of claim 7 , wherein the digitized signal is a pulse modulated continuous wave signal, and the detection threshold is calculated as proportional to a peak sample value of the first baseband signal or as proportional to an average of sample values of the first baseband signal.
11 . The computer program product of claim 7 , wherein the digitized signal is a spread spectrum signal, and the detection threshold is calculated as proportional to a correlation of the first baseband signal and a spreading function.
12 . The computer program product of claim 7 , wherein the digitized signal is an identification friend or foe (IFF) interrogator signal, and the process comprises detecting an IFF suppression pulse based on the first baseband signal.
13 . A method for signal detection, the method comprising: down converting, by a processor-based system, a digitized signal to a first baseband signal at a first decimation rate such that the first baseband signal is provided at a first latency with a first signal to noise ratio (SNR), the first latency and the first SNR based on the first decimation rate; down converting, by the-processor based system, the digitized signal to a second baseband signal at a second decimation rate such that the second baseband signal is provided at a second latency with a second SNR, the second latency and the second SNR based on the second decimation rate, wherein the second decimation rate is greater than the first decimation rate, the second latency is greater than the first latency, and the second SNR is greater than the first SNR; and generating, by the processor-based system, a detection threshold based on the first baseband signal, the detection threshold generated prior to completion of the generation of the second baseband signal.
14 . The method of claim 13 , further comprising: generating a down-conversion frequency signal; mixing the digitized signal with the down-conversion frequency signal to generate a mixed signal; decimating the mixed signal at the first decimation rate to generate a first decimated signal; filtering high frequency noise from the first decimated signal to generate the first baseband signal; decimating the mixed signal at the second decimation rate to generate a second decimated signal; and filtering high frequency noise from the second decimated signal to generate the second baseband signal.
15 . The method of claim 13 , further comprising attenuating, using an infinite impulse response filter, a high frequency noise from the first decimated signal, and attenuating, using a finite impulse response filter, a high frequency noise from the second decimated signal.
16 . The method of claim 13 , wherein the digitized signal is a pulse modulated continuous wave signal, and the detection threshold is calculated as proportional to a peak sample value of the first baseband signal or as proportional to an average of sample values of the first baseband signal.
17 . The method of claim 13 , wherein the digitized signal is a spread spectrum signal, and the detection threshold is calculated as proportional to a correlation of the first baseband signal and a spreading function.

Description

STATEMENT OF GOVERNMENT INTEREST This invention was made with United States Government assistance under Contract No. FA8232-17-D-0027/FA8232-21-F-0286. The United States Government has certain rights in this invention. FIELD OF DISCLOSURE The present disclosure relates to signal detection, and more particularly to reduced latency look-ahead for a signal detection system. BACKGROUND Radar systems often have requirements for relatively rapid response times after detection of a signal of interest. For example, the time required to detect a signal and act upon that detection may be constrained based on operational requirements. Additionally, such systems may have requirements to detect signals at relatively low power levels. Meeting both sets of requirements simultaneously can be challenging. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a radar system including a detector with reduced latency look-ahead, in accordance with certain embodiments of the present disclosure. FIG. 2 is a block diagram of the detector with reduced latency look-ahead of FIG. 1, configured in accordance with certain embodiments of the present disclosure. FIG. 3 is a block diagram of the reduced latency channel of the detector of FIG. 2, configured in accordance with certain embodiments of the present disclosure. FIG. 4 is a block diagram of the high signal to noise ratio (SNR) channel of the detector of FIG. 2, configured in accordance with certain embodiments of the present disclosure. FIG. 5 is a flowchart illustrating a methodology for signal detection based on reduced latency look-ahead, in accordance with an embodiment of the present disclosure. FIG. 6 is a block diagram of a processing platform configured to provide a signal detection system comprising a low latency channel and a high SNR channel, in accordance with an embodiment of the present disclosure. Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications, and variations thereof will be apparent in light of this disclosure. DETAILED DESCRIPTION Techniques are provided herein for a signal detector with reduced latency look-ahead capability. The techniques are particularly useful in the context of a radar system, but can be used in other applications that can benefit from reduced latency look-ahead capability. As noted above, simultaneously meeting the requirements for both rapid response to signal detection and the ability to detect signals at relatively low power levels can be challenging for a given signal detection system. To this end, and in accordance with an embodiment of the present disclosure, a signal detection system is disclosed which provides first and second channels. The first channel is configured to provide reduced latency, and the second channel is configured for higher SNR operation. The reduced latency channel applies a lower decimation rate in conjunction with a wider decimation filter. This results in a lower SNR but reduces latency of the samples. Signal detection applications that require reduced latency and that can function with a lower SNR may be fed from this channel. In contrast, the second channel, or high SNR channel, applies a higher decimation rate in conjunction with a narrower decimation filter. This results in a higher SNR but increases delay or latency of the samples. Signal detection applications that require a higher SNR input and that can function with greater latency can be fed from this channel. In some such examples, the reduced latency channel can be employed to provide an early detection threshold that is useful to a detector that processes the later arriving signal delivered from the high SNR channel, as will be explained in greater detail below. In an example, a signal detection system includes a first processing channel (e.g., a reduced latency channel) configured to down convert a digitized signal to a first baseband signal (e.g., in-phase and quadrature or I/Q samples) at a first decimation rate such that the first baseband signal is provided at a first latency with a first SNR. The first latency and the first SNR are based on the first decimation rate. The system also includes a second processing channel (e.g., a high SNR channel) configured to down convert the digitized signal to a second baseband signal (I/Q samples) at a second decimation rate such that the second baseband signal is provided at a second latency with a second SNR. The second latency and the second SNR are based on the second decimation rate. The second decimation rate is greater than the first decimation rate, such that the second latency is greater than the first latency and the second SNR is greater than the first SNR. The system further includes a detection threshold calculator configured to generate a detection threshold based on the first baseband signal. The detection threshold is generated prior to completion of the generation of the second baseband signal.