ELECTRONIC SCANNING RADAR APPARATUS

• US 20080036645A1
• Filed: 02/20/2007
• Published: 02/14/2008
• Est. Priority Date: 02/27/2006
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Watanabe, Yuu, Sakamoto, Mai, Yamano, Chiharu, Natsume, Kazuma
• Granted Patent: US 7,495,604 B2
• Time in Patent Office: Days
• US Class Current: 342/109
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 7/023 Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques auxiliary means for detecting or identifying radar signals or the like G01S7/021; means for anti-jamming G01S7/36
• CPC Class Codes: G01S 7/352 Receivers
• CPC Class Codes: G01S 7/356 involving particularities of FFT processing
• CPC Class Codes: G01S 7/4021 of receivers

Abstract

A sampled beat signal is cut out into two or more short time data in a time direction concerning each antenna component. From a frequency spectrum of the short time data, an interference element frequency of an interference wave is detected. From the interference element frequency of the interference wave, two or more candidates of the frequency before aliasing of the interference wave are produced, and phase correction is executed on each candidate. Digital Beamforming is executed on the corrected frequency so as to extract maximum peaks of the power of an azimuth direction, and the frequency candidate showing the maximum peak power is selected and the arrival azimuth of the interference element is estimated. A filter for suppressing the interference element is applied on the short time data from the estimated arrival azimuth of the interference element so as to suppress the interference element.

Claims

1. Electronic scanning radar apparatus, having

a transmission antenna for ejecting a transmitted signal which is comprised of a continuous wave;

a reception antenna which is comprised of two or more antenna components;

a mixer for mixing a received signal received by each of said two or more antenna components and said transmitted signal and for obtaining beat signals for two or more channels corresponding to said two or more antenna components;

a switcher provided between said mixer and said two or more antenna components, for selectively connecting said two or more antenna components with said mixer;

an A/D converter for sampling said beat signal obtained by said mixer with a predetermined sampling frequency and for obtaining received data respectively corresponding to said two or more antenna components for two or more channels; and

a target detector for detecting distance and relative speed of a target on the basis of said receiving data for said two or more channels which is sampled by said A/D converter, said electronic scanning radar apparatus, comprising;

a short time data cutting for cutting said sampled received data for two or more channels into two or more short time data in a time direction for each channel;

a frequency spectrum computing portion for computing frequency spectra of said two or more short time data for each said channel;

an interference frequency detector for detecting an interference element frequency of an interference wave from said frequency spectra;

two or more phase correctors, each corrector for producing two or more candidates of a frequency before aliasing of said interference wave from said interference element frequency of said interference wave, and for computing phase correcting amount for each candidate, and for correcting phase on said interference element frequency on the basis of said phase correcting amount;

two or more maximum peak direction extractors, each extractor for executing Digital Beamforming processing on said interference element frequency after respective phase corrections, and for extracting the maximum peak in an electric power of an azimuth direction on said each frequency candidate;

an interference direction selecter for selecting said frequency candidate showing the maximum peak power of the maximum peaks of said respective frequency candidates, and for estimating an arrival azimuth of said interference element from said azimuth of said maximum peak power of said selected frequency candidate;

an interference direction element remover for applying a filter for suppressing said interference element to said short time data cut out by said short time data cutting in said estimated arrival azimuth of said interference element so as to suppress said interference element; and

a buffer for merging said short time data wherein said interference element has been suppressed and for restoring to data having length before cutting;

whereby distance and relative speed of said target are detected on the basis of said restored data.

3. The electronic scanning radar apparatus according to claim 1, further comprising a signal suppressing amount map producer for computing and outputting lowered amount of said beat signal excluding said interference element suppressed by said filter in said interference direction element remover on the basis of said arrival azimuth of said interference element estimated by said interference direction selecter as a signal suppressing amount map.

2. Electronic scanning radar apparatus, having

a transmission antenna for ejecting a transmitted signal which is comprised of a continuous wave;

a reception antenna which is comprised of two or more antenna components;

a mixer for mixing a received signal received by each of said two or more antenna components and said transmitted signal and for obtaining beat signals for two or more channels corresponding to said two or more antenna components;

a switcher provided between said mixer and said two or more antenna components, for selectively connecting said two or more antenna components with said mixer;

an A/D converter for sampling said beat signal obtained by said mixer with a predetermined sampling frequency and for obtaining received data respectively corresponding to said two or more antenna components for two or more channels; and

a target detector for detecting distance and relative speed of a target on the basis of said receiving data for said two or more channels which is sampled by said A/D converter, said electronic scanning radar apparatus, comprising;

a short time data cutting for cutting said sampled received data for two or more channels into two or more short time data in a time direction for each channel;

a frequency spectrum computing portion for computing frequency spectra of said two or more short time data for each said channel;

an interference frequency detector for detecting an interference element frequency of an interference wave from said frequency spectra;

two or more phase correctors, each corrector for producing two or more candidates of a frequency before aliasing of said interference wave from said interference element frequency of said interference wave, and for computing phase correcting amount for each candidate, and for correcting phase on said interference element frequency on the basis of said phase correcting amount;

two or more maximum peak direction extractors, each extractor for executing Digital Beamforming processing on said interference element frequency after respective phase corrections, and for extracting the maximum peak in an electric power of an azimuth direction on said each frequency candidate;

an interference direction selecter for selecting said frequency candidate showing the maximum peak power of the maximum peaks of said respective frequency candidates, and for estimating an arrival azimuth of said interference element from said azimuth of said maximum peak power of said selected frequency candidate;

a memory for storing in advance two or more transition patterns of said beat frequency of said interference element which may occur at the time of mixing with said interference wave in said mixer;

a filter for correcting frequency before aliasing, for comparing said frequency before aliasing of said interference wave estimated by said interference direction selecter and said two or more transition patterns in said memory so as to judge to which transition pattern of these transition patterns said estimated frequency before aliasing of said interference wave can be applied and for selecting the pattern, and correcting an estimated result of said frequency before aliasing of said interference wave on the basis of said selected transition pattern, and for outputting said result; and

an interference direction element remover for applying a filter for suppressing said interference element to said sampled received data for said two or more channels on the basis of said arrival azimuth of said estimated interference element and said estimated result of said corrected frequency before aliasing of said interference wave outputted from said transition correcting filter so as to suppress said interference element of said received data.