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CN-116736284-B - High-precision speed measurement method for FSK radar and computer readable medium

CN116736284BCN 116736284 BCN116736284 BCN 116736284BCN-116736284-B

Abstract

The invention discloses a high-precision speed measurement method for FSK radar and a computer readable medium. The method comprises the steps of carrying out N-point sampling on an echo signal reflected by a target and a difference frequency signal after mixing with a transmitting signal of the echo signal received by an FSK radar to obtain two paths of discrete difference frequency signals with different frequencies, carrying out fast Fourier transform on the two paths of discrete difference frequency signals to obtain FFT spectrums of the two paths of discrete difference frequency signals, taking the frequency of the peak positions of the spectrums as rough estimated frequencies respectively, taking the adjacent spectral line ranges on two sides of the rough estimated frequencies as reference intervals, calculating a periodic chart according to the reference intervals, taking the frequency corresponding to the periodic chart reaching the maximum value as final fine estimated frequency, and calculating the speed of the target based on the fine estimated frequency. The method can obtain the specific value of the required frequency more accurately, thereby improving the speed measurement precision of the FSK radar, and compared with a CZT algorithm, the method can greatly reduce the operation amount, thereby being better applied to engineering.

Inventors

  • SHENG ZHICHAO
  • LIN MIN
  • Peng Yechao

Assignees

  • 睿迪纳(无锡)科技有限公司

Dates

Publication Date
20260512
Application Date
20230706

Claims (7)

  1. 1. A high accuracy speed measurement method for an FSK radar, comprising: step 1, carrying out N-point sampling on a difference frequency signal obtained by mixing an echo signal reflected by a target and a transmitting signal received by an FSK radar to obtain two paths of discrete difference frequency signals with different frequencies; Step 2, performing fast Fourier transform on the two paths of discrete difference frequency signals to obtain FFT spectrums of the two paths of discrete difference frequency signals, and taking the frequencies of the spectrum peak positions of the FFT spectrums as rough estimated frequencies respectively; Step 3, taking the adjacent spectral line ranges on two sides of the rough estimated frequency as a reference interval, calculating a periodic chart according to the reference interval, and taking the frequency corresponding to the periodic chart reaching the maximum value as the final fine estimated frequency; and 4, calculating the speed of the target based on the fine estimated frequency.
  2. 2. A high accuracy speed measurement method for FSK radar according to claim 1, wherein the discrete difference frequency signal is expressed as: Wherein, the I= {1,2}, n=0, 1..n-1, In order to be a doppler frequency, The frequency of the transmitted signal, C is the speed of light, T s is the sampling period, and R 0 is the target position at zero time.
  3. 3. A high precision velocimetry for FSK radar according to claim 2, characterized in that the FFT spectrum of the discrete difference frequency signal is represented as: Wherein, the For the FFT spectrum of the i-th discrete difference signal, k=0, 1..n-1, e j(.) is the phase spectrum of the fourier transform, λ i is the wavelength of the transmitted signal; The corresponding frequencies of the spectrum peak positions are: Wherein, the For the peak position of the FFT spectrum of the i-th discrete difference signal, f i is the rough estimated frequency of the FFT spectrum of the i-th discrete difference signal, and f s is the sampling frequency of the signal.
  4. 4. A high accuracy speed measurement method for FSK radar according to claim 3, wherein the reference interval is (f i -Δf,f i +Δf), where Δf=f s /N.
  5. 5. The method for high-precision velocimetry for FSK radar according to claim 4, wherein the periodic chart is calculated in the following manner: Wherein, the For the calculated periodogram, T is the transpose of the matrix, x is the observation sequence of the difference frequency signal, x= [ x (0), x (1),.., x (N-1) ], Then searching for the reference interval (f i -Δf,f i +Δf) The value is the largest As a fine estimated frequency
  6. 6. The method for high accuracy speed measurement of FSK radar according to claim 5, wherein the speed of the target is calculated as follows:
  7. 7. a computer readable medium storing a computer program, which when executed by a processor implements the method of any one of claims 1-6.

Description

High-precision speed measurement method for FSK radar and computer readable medium Technical Field The invention relates to the technical field of radar speed measurement, in particular to a high-precision speed measurement method for an FSK radar and a computer readable medium. Background Radar is an electronic device that detects the spatial position of a target using electromagnetic waves, and obtains desired information by processing and analyzing a transmission signal and a received echo signal. Radar is now widely used in many fields, such as automotive scenes, structural health monitoring, biomedical environments, etc. The radar waveforms used are different depending on the application scenario. For example, the frequency modulation continuous wave radar (Frequency Modulate Continuous WAVE RADAR, FMCW) has the characteristics of rich frequency modulation waveforms, strong anti-interference capability and the like, and is suitable for the aspects of automobile obstacle avoidance functions and the like. Frequency shift keying (Frequency SHIFT KEYING, FSK) continuous wave radar is receiving attention of researchers in many fields due to the advantages of low hardware cost, low Frequency band resource requirement and the like. Therefore, research on how to improve the speed measurement accuracy based on the FSK radar has important significance. The FSK radar mainly acquires speed information through Doppler effect, frequency information is usually acquired by Fourier transform, the frequency resolution is often not ideal enough due to fence effect caused by continuous signal discretization, and the conventional improved method is performed from the two aspects of controlling the sampling point to be unchanged, reducing the sampling rate or controlling the sampling rate to be unchanged and increasing the sampling point. The method has the defects of high complexity, high consumption of computing resources, high storage cost and the like. Disclosure of Invention The invention aims at overcoming the defects in the prior art and provides a high-precision speed measurement method for an FSK radar and a computer readable medium. To achieve the above object, in a first aspect, the present invention provides a high-precision speed measurement method for an FSK radar, including: step 1, carrying out N-point sampling on a difference frequency signal obtained by mixing an echo signal reflected by a target and a transmitting signal received by an FSK radar to obtain two paths of discrete difference frequency signals with different frequencies; Step 2, performing fast Fourier transform on the two paths of discrete difference frequency signals to obtain FFT spectrums of the two paths of discrete difference frequency signals, and taking the frequencies of the spectrum peak positions of the FFT spectrums as rough estimated frequencies respectively; Step 3, taking the adjacent spectral line ranges on two sides of the rough estimated frequency as a reference interval, calculating a periodic chart according to the reference interval, and taking the frequency corresponding to the periodic chart reaching the maximum value as the final fine estimated frequency; and 4, calculating the speed of the target based on the fine estimated frequency. Further, the discrete difference frequency signal is expressed as: Wherein, the I= {1,2}, n=0, 1..n-1,In order to be a doppler frequency,The frequency of the transmitted signal, C is the speed of light, T s is the sampling period, and R 0 is the target position at zero time. Further, the FFT spectrum of the discrete difference signal is expressed as: Wherein, the For the FFT spectrum of the i-th discrete difference signal, k=0, 1..n-1, e j(·) is the phase spectrum of the fourier transform, λ i is the wavelength of the transmitted signal; The corresponding frequencies of the spectrum peak positions are: Wherein, the For the peak position of the FFT spectrum of the i-th discrete difference signal, f i is the rough estimated frequency of the FFT spectrum of the i-th discrete difference signal, and f s is the sampling frequency of the signal. Further, the reference interval is (f i-Δf,fi +Δf), where Δf=f s/N. Further, the periodic chart is calculated as follows: Wherein, the For the calculated periodogram, T is the transpose of the matrix, X is the observation sequence of the difference frequency signal, x= [ X (0), X (1),.., X (N-1) ], Then searching for the reference interval (f i-Δf,fi +Δf)The value is the largestAs a fine estimated frequency Further, the speed of the target is calculated as follows: In a second aspect, the invention provides a computer readable medium storing a computer program which when executed by a processor implements the method described above. The method has the advantages that the FFT conversion is combined with the frequency estimation, the specific value of the required frequency is obtained more accurately, so that the speed measurement precision of the FSK