IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0252005
(2002-09-23)
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우선권정보 |
DE-0046643 (2001-09-21) |
발명자
/ 주소 |
- Bickert, Bernhard
- Meyer-Hilberg, Jochen
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출원인 / 주소 |
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대리인 / 주소 |
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인용정보 |
피인용 횟수 :
1 인용 특허 :
7 |
초록
▼
In a process for computing the radar signals present at the output of two subapertures of an antenna of a two-channel radar system, the two subaperture channels are combined by means of a wave guide part to a sum and difference channel, and the signals of the sum and difference channel are used to c
In a process for computing the radar signals present at the output of two subapertures of an antenna of a two-channel radar system, the two subaperture channels are combined by means of a wave guide part to a sum and difference channel, and the signals of the sum and difference channel are used to compute the radar signals at the subaperture channels. The signals of the two subaperture channels are computed from the amplitude- and phase-shifted sum and difference channel signal by being placed in the following equations: wherein X1(r,f), X2(r,f): Frequency spectrum of the two subaperture channels; XS(r,f),XD(r,f): Frequency spectrum of the sum and difference channel, r: distance cell, f: Doppler frequency, Φ0: phase correction factor, and a0: amplitude correction factor.
대표청구항
▼
1. A process for computing radar signals present at subapertures of an antenna of a two-channel radar system, comprising: combining two subaperture channels by means of a wave guide element to form a sum and difference channel; and using signals of the sum and difference channel to compute the r
1. A process for computing radar signals present at subapertures of an antenna of a two-channel radar system, comprising: combining two subaperture channels by means of a wave guide element to form a sum and difference channel; and using signals of the sum and difference channel to compute the radar signals at the subaperture channels; wherein, the signals of the two subaperture channels are computed from amplitude- and phase-shifted sum and difference channel signal according to the relation X1(r,f), X2(r,f) are frequency spectra of the two subaperture channels; XS(r,f),XD(r,f) are frequency spectra of the sum and difference channel; r is the distance cell; f is the Doppler frequency; Φ0is the phase correction factor; and a0is the amplitude correction factor. 2. The process according to claim 1, wherein the phase correction factor Φ0is estimated by a process comprising: computing the Doppler frequency position of the major lobe clutter; correcting the sum and difference channel signal, wherein, for each of the various distance gates in the phase, the sum and difference channel signal is shifted as a function of the pulse repetition time into the frequency zero position; filtering corrected sum and difference channel signals via a low pass filter for suppressing high-frequency phase noise; reducing a scanning rate of the sum and difference channel signal to reduce processing time and increase spectral resolution; transforming the filtered sum and difference channel signal XS(r,t), XD(r,t) via a windowed Fast Fourier transformation (FFT) into a Doppler frequency range; for each Doppler frequency position, computing a cross-correlation of the sum and difference channel signal XS(r,f), XD(r,f) by way distance gates; determining a course of a phase difference between the sum and difference channel signals XS(r,f), XD(r,f) from said cross-correlations, by way of an adaptively computed frequency range; and determining a phase correction factor Φ0by computing the arithmetic mean value of the phase difference between the sum and difference channel by way of a frequency range of said major lobe clutter. 3. The process according to claim 1, wherein the amplitude correction factor a0is estimated by a process comprising: computing spectra for the two subaperture channels according equations (1) and (2) with a0=1; computing a mean spectrum for one and the other subaperture channel by taking the geometric mean of the spectra computed in equation (1) and (2) over different distance gates; computing a mean difference spectrum from the mean spectrum of one and the other subaperture channel; determining the amplitude correction factor a0as an arithmetic mean value of a difference over the frequency range of said major lobe clutter of the phase correction computation. 4. The process according to claim 1, wherein: estimation takes place on the basis of a packet of signal pulses; a frequency distribution of the estimated values is computed for each pulse packet; and a value with a greatest frequency is used as the estimated value.
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