A Hovering Helicopter Detection Method Based on Time Domain Autocorrelation of Rotor Echo Signals
A technology of echo signal and detection method, applied in radio wave measurement system, radio wave reflection/re-radiation, measurement device, etc., can solve slow or hovering helicopter pulse Doppler radar system detection performance degradation, helicopter Low flight altitude and other issues, to achieve the effect of simple design, good versatility, and small amount of calculation
Active Publication Date: 2018-04-17
SHANGHAI RADIO EQUIP RES INST
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Problems solved by technology
The main difficulty in the detection of slow or hovering helicopters is that the helicopter’s flying altitude is low, and the Doppler frequency of the echo of the fuselage is close to zero frequency and superimposed with the ground clutter, which is greatly affected by the ground-sea clutter. The Doppler radar system cannot use the body echo Doppler information for detection and identification, resulting in a serious decline in the detection performance of the pulse Doppler radar system for slow or hovering helicopters
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[0025] based on the following Figure 1 to Figure 4 , specifically explain the preferred embodiment of the present invention.
[0026] Ordinary radar target echo energy is continuous in the time domain, and is accumulated and concentrated in the Doppler frequency domain. On the contrary, the helicopter rotor echo is shown as a periodic scintillation pulse in the shape of a Sinc function in the time domain, which is a periodic The scintillation pulses are permanent and hour-wide, and the pulse decays rapidly after the peak. There is almost no rotor echo energy before the next scintillation pulse, but it is scattered in the Doppler frequency domain, and there is broadening, so it is unlikely to be coherently accumulated. For rotor echo detection, radar echoes from the fuselage of a slow or hovering helicopter can be considered target clutter. When the rotor echo is detected in the time domain, the signal has the maximum instantaneous power, which has certain advantages. If the ...
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The invention discloses an auto-correlative hovering helicopter detection method based on rotor echo signal time domain, comprising steps of performing intermediate frequency sampling on echo signal data, performing analog-to-digital conversion on sampled data, performing digit orthogonalization processing on converted digital signals, converting sampled data to a baseband signal, calculating the baseband signal module value, performing constant false alarm detection, performing time domain window position searching according to the constant false alarm detection result, detecting scintillation pulse signal data, extracting the scintillation pulse signal, calculating a scintillation cycle, combining the extracted scintillation pulse signal into a new series, performing auto-correlative processing on the scintillation pulse series to obtain an auto-correlative sequence, performing constant false alarm detection on the self-correlative sequence, and finishing the slow speed or hovering helicopter detection identification according to the constant false alarm detection result The invention is simple in design, small in calculated quantity, good in universality and easy to implement.
Description
technical field [0001] The invention relates to a hovering helicopter detection method based on time-domain autocorrelation of rotor echo signals, and is particularly suitable for detection and identification of hovering helicopters by a pulse Doppler radar system of a single frequency domain detection system. Background technique [0002] The intermediate frequency sampling of the helicopter echo in the traditional pulse Doppler radar system is mainly composed of four parts: the fuselage echo, the rotor echo, the ground clutter and the receiver thermal noise. For sports helicopters, there is Doppler in the echo of the fuselage, and the radar system uses the Doppler information to extract guidance information. The main difficulty in the detection of slow or hovering helicopters is that the helicopter’s flying altitude is low, and the Doppler frequency of the echo of the fuselage is close to zero frequency and superimposed with the ground clutter, which is greatly affected by...
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IPC IPC(8): G01S7/41G01S13/50
CPCG01S7/412G01S13/50
Inventor 汤继伟王树文赵学州吴振凯李俊山郭冬梅
Owner SHANGHAI RADIO EQUIP RES INST