Method for improving ranging precision of radar based on Gaussian interpolation

[0031] Further, the drawings are further described with reference to the present invention:

[0032] Using the priori information, under the premise of the sampling rate, the bandwidth, and the window function and the noise, select the higher reference sampling rate to fit the echo pulse pressure of the 3DB beam width into a Gaussian distribution function, no matter Whether the amplitude of the pulse pressure results is normalized, the fitting Gaussian distribution variance is a certain constant. Selecting a higher sampling rate to get enough sampling points within the 3DB beam width, and then use the real sampling rate to normalize the sampling time, then use one of the corresponding sample points to fit the Gaussian distribution function. , Get the uniquely determined fitting part of the franchise at this time. Only the maximum value and the second large value sampling point are taken in the echo pulse pressure, and the sample time is normalized to the sampling time unit, and the variance value obtained by combined with the priori information can be treated. It is estimated that the mean of the proposed Gaussian distribution function is estimated, that is, the sampling time unit that occurs in the return peak, and then the returning peak time can be obtained by simple calculation conversion. Using the true sample rate, the position information and amplitude information of the pulse voltage is sampled, and there is no need to workmatively processing the amplitude information, and the gauges can be obtained directly to the sampling position of the return peak. Decrease the distance quantization error, improve the accuracy of radar ranging accuracy. Specific steps are as follows:

[0033] Step 1, the time width t selected in the given project, bandwidth B, sampling rate f s1 And the window function information, in the case of noise, by high sample rate f s2 The simulation analysis of the designed waveform is pulsed, and the sample time is normalized to the sampling time unit with the real sampling rate. Due to only two sampling points in the 3DB beam width, select two sampling time intervals (2 * 1 / f) s1 The sampling time unit data and amplitude data of the inner pulse pressure waveform are combined to obtain a probability density function of the Gaussian distribution, that is, the determined variance value is obtained. For example, the radar parameter design is the time width t = 20us, bandwidth b = 2MHz, sampling rate f, respectively s1 = 2.5MHz, window function Select Hamming Window, Reference Sample R s2 = 50MHz, after the pulse compression and sampling time are normalized, the sampling time unit of the selected partial pulse pressure waveform is 23, 23.05, 23.10 ... 24, 24.05 ...... 25, see figure 2 , The fitted Gaussian distribution curve and probability density function see image 3 , According to the probability density function, the difference is 1.0161;

[0034] Step 2, the maximum value of the pulse pressure of the pulse pressure of the pulse pressure of the pulse pressure after the addition of Gaussian white noise is treated with the Gaussian interpolation processing, which is obtained to fit the mean of the Gaussian distribution function, that is, the return peak value corresponds. Sampling time unit. details as follows:

[0035] Gauss distribution probability density function general expression:

[0036]

[0037] Among them, T 0 Indicates the mean of the Gaussian distribution, and σ represents the variance of the Gaussian distribution. Assuming that the actual two sampling points is Y. 1 Sum 2 , The corresponding sampling time unit is T 1 T 2 There is:

[0038]

[0039] Slimming can get T 0 The expression is:

[0040]

[0041] Since the variance value has been obtained in step 1, T 1 , T 2 Sum 1 Y 2The mean of the Gaussian distribution function can be obtained by substituting the above formula, that is, the sampling time unit corresponding to the return peak;

[0042] Step 3, convert the sampling time unit into a sampling time. Since the sampling time unit is gave to the sampling time with a real sampling rate, the T obtained in step 3 is 0 The corresponding sampling time is T 0 / f s1;

[0043] Step 4, determine the distance after the interpolation processing according to the sampling time corresponding to the echo peak The reduced distance quantization error is:

[0044]

[0045] Under the radar parameters designed in step 1, when the SNR is taken between 10 and 30 dB, the resulting distance quantization error is reduced from 13.1m to 0.9m, which significantly improves the ranging accuracy, and meets the actual demand. .

[0046] During the process of the present invention, the experimental parameter design bandwidth b is 2MHz, the sample rate f S1 For 2.5MHz, the window function selects the Hamming window, by simulation analysis at a higher sampling rate 50MHz, fitting the echo pulse compaction of the 3dB beam width into a Gaussian distribution function, the standard difference of the Gaussian distribution function is 1.0161 The maximum value and the second large value sampling point of the real sample rate 2MHz is then treated with the Gaussian distribution function, which estimates the mean of the Gaussian distribution function, that is, the sampling position corresponding to the return peak. After experimental verification, when the SNR is only 10dB, the final distance quantization error maximum is controlled at 13.1m. This method is compared to the parabola interpolation algorithm, the step is simple, the amount is small, and since the sample point SNR is selected due to the selected main lobe, the fitted model is more matching with the actual pulse pressure, and the error is smaller. Under the same parameter design, the comparison of the two methods see Figure 6. Experiments have shown that this method has a significant effect on improving radar ranging accuracy.

[0047] The method of the invention is not limited to the above examples. Various modifications or modifications can be made using the principles and methods of the present invention, but these improvements are within the scope of the invention.