CN-121559534-B - Radar ranging method and device and radar level gauge

CN121559534BCN 121559534 BCN121559534 BCN 121559534BCN-121559534-B

Abstract

The invention relates to the technical field of radar ranging, and discloses a radar ranging method, a radar ranging device and a radar level gauge, wherein the radar ranging method comprises the steps of receiving a plurality of echo signals reflected by a ranging target, and superposing the echo signals to obtain a superposed echo signal; the method comprises the steps of screening a plurality of target spectral lines from a frequency spectrum of a superimposed echo signal, carrying out Rife interpolation on the basis of the plurality of target spectral lines to obtain a plurality of interpolation points, calculating initial distances between the target interpolation points and a ranging target, screening a plurality of target interpolation points from the plurality of interpolation points on the basis of the initial distances, carrying out cubic spline interpolation on the basis of the plurality of target interpolation points to obtain a cubic spline interpolation function, and substituting the initial distances into the cubic spline interpolation function to obtain the target distances. According to the radar ranging method, the plurality of echo signals reflected by the ranging target are overlapped, so that noise can be obviously restrained, the signal to noise ratio is improved, and the efficient and accurate radar ranging is realized by adopting double interpolation of local fine Rife interpolation and global optimized cubic spline interpolation.

Inventors

Ye Zhizeng
WANG ZHIGANG
WU JIE
ZOU LINA
ZHENG ZHAN

Assignees

浙江美仪智能传感技术有限公司
杭州美仪自动化有限公司

Dates

Publication Date: 20260508
Application Date: 20260122

Claims (10)

1. A radar ranging method, the method comprising: receiving a plurality of echo signals reflected by a ranging target, and superposing the echo signals to obtain a superposed echo signal; Screening a plurality of standard spectral lines from the frequency spectrum of the superimposed echo signals; Performing Rife interpolation based on the multi-item standard spectral line to obtain a plurality of interpolation points, and calculating the initial distance between the interpolation points and the ranging target; screening a plurality of target interpolation points from the plurality of interpolation points based on the initial distance; and performing cubic spline interpolation based on the target interpolation points to obtain a cubic spline interpolation function, and substituting the initial distance into the cubic spline interpolation function to obtain the target distance.
2. The method of claim 1, wherein the target spectral line comprises a peak spectral line, a left adjacent spectral line adjacent to the peak spectral line, and a right adjacent spectral line; When the amplitude of the left adjacent spectral line is greater than the amplitude of the right adjacent spectral line, the initial distance is calculated by the following formula: when the amplitude of the left adjacent spectral line is smaller than the amplitude of the right adjacent spectral line, the initial distance is calculated by the following formula: wherein distance represents an initial distance; DeltaR represents the distance grid; representing the greater of the frequencies of the left adjacent spectral line and the right adjacent spectral line; representing the smaller of the frequencies of the left adjacent line and the right adjacent line, and RES representing the frequency difference between any two adjacent interpolation points.
3. The method of claim 1, wherein the screening a plurality of target interpolation points from the plurality of interpolation points based on the initial distance comprises: obtaining the distance corresponding to each interpolation point, and sorting the interpolation points in descending order according to the distance; Traversing each sequenced interpolation point, and determining a plurality of related interpolation points of the interpolation points; Judging whether the interpolation points meet a first condition or not based on the initial distance, the distance corresponding to the interpolation points and the distance corresponding to each relevant interpolation point; And when the interpolation point does not meet the first condition, traversing the next interpolation point until the interpolation point meets the first condition, and determining the interpolation point and a plurality of corresponding related interpolation points as the target interpolation points.
4. A method according to claim 3, wherein the first condition is expressed by the following formula: wherein, i represents the index of the interpolation point, i-1, i+1, i+2 represent the index of the relevant interpolation point respectively; Representing the distance corresponding to the interpolation point; Respectively represent the corresponding distance of the relevant interpolation points, distance represents the initial distance, and N represents the total number of interpolation points.
5. The method according to claim 4, wherein the method further comprises: and when all the interpolation points do not meet the first condition, determining the interpolation points meeting any second condition as the target interpolation points.
6. The method of claim 5, wherein the second condition is represented by the formula: where distance represents the initial distance and N represents the total number of interpolation points.
7. The method according to claim 1, wherein performing cubic spline interpolation based on the target interpolation points to obtain a cubic spline interpolation function, substituting the initial distance into the cubic spline interpolation function to obtain a target distance, includes: Respectively constructing a cubic polynomial for each interpolation interval formed by the target interpolation points; constructing a matrix equation based on a plurality of cubic polynomials by adopting a free boundary condition, wherein the order of the matrix equation is consistent with the number of the target interpolation points; solving the matrix equation by adopting a catch-up method to obtain a cubic spline interpolation function corresponding to each interpolation interval; Substituting the initial distance into a cubic spline interpolation function of an interpolation interval where the initial distance is located, and obtaining the target distance.
8. The method of claim 1, wherein the superimposing the plurality of echo signals results in a superimposed echo signal, comprising: Aligning pulse phases of the plurality of echo signals; and aligning the echo signals according to sampling positions, then carrying out point-by-point summation, and obtaining the superimposed echo signals through amplitude normalization.
9. A radar ranging device, the device comprising: The superposition module is used for receiving a plurality of echo signals reflected by the ranging target, and superposing the echo signals to obtain superposition echo signals; The first screening module is used for screening a plurality of standard spectral lines from the frequency spectrum of the superimposed echo signals; The first interpolation module is used for carrying out Rife interpolation based on the multi-item standard spectral line to obtain a plurality of interpolation points and calculating the initial distance between the first interpolation module and the ranging target; the second screening module is used for screening a plurality of target interpolation points from the plurality of interpolation points based on the initial distance; and the second interpolation module is used for carrying out cubic spline interpolation based on the target interpolation points to obtain a cubic spline interpolation function, and substituting the initial distance into the cubic spline interpolation function to obtain the target distance.
10. A radar level gauge, comprising: A memory and a processor in communication with each other, the memory having stored therein computer instructions, the processor executing the computer instructions to perform the radar ranging method of any of claims 1 to 8.

Description

Radar ranging method and device and radar level gauge Technical Field The invention relates to the technical field of radar ranging, in particular to a radar ranging method and device and a radar level gauge. Background The radar level gauge measures distance by transmitting a signal and receiving a target reflected signal and utilizing the frequency difference (i.e. beat frequency) of the two signals. In the conventional radar ranging process, the continuous beat spectrum is scattered into fence-shaped spectral lines with fixed intervals by the fast fourier transform, and the ranging result is accurate only when the real beat frequency of a ranging target just falls on a certain fence. If the true difference frequency is between two fences, a fence effect error can be generated. To alleviate this problem, a conventional approach is to increase the number of fourier transform points to increase the spectral resolution. However, the method can greatly improve the demands on the operand and the storage capacity, not only causes the rising of the hardware cost and the increasing of the design difficulty, but also prolongs the signal processing time and reduces the ranging efficiency of the radar. Disclosure of Invention The invention provides a radar ranging method and device and a radar level gauge, which are used for solving the problems that the number of Fourier transform points is increased to greatly increase the demands on the operation amount and the storage capacity, the hardware cost is increased, the design difficulty is increased, the signal processing time is prolonged, and the ranging efficiency of a radar is reduced in the traditional radar ranging. In a first aspect, the present invention provides a radar ranging method, the method comprising: receiving a plurality of echo signals reflected by a ranging target, and superposing the echo signals to obtain a superposed echo signal; Screening a plurality of standard spectral lines from the frequency spectrum of the superimposed echo signals; Performing Rife interpolation based on the multiple target spectral lines to obtain multiple interpolation points, and calculating the initial distance between the multiple interpolation points and a ranging target; Screening a plurality of target interpolation points from the plurality of interpolation points based on the initial distance; And performing cubic spline interpolation based on the plurality of target interpolation points to obtain a cubic spline interpolation function, and substituting the initial distance into the cubic spline interpolation function to obtain the target distance. According to the invention, by superposing a plurality of echo signals reflected by the ranging target, noise can be obviously suppressed, and the signal-to-noise ratio can be improved. Multiple target spectral lines are screened from the frequency spectrum of the superimposed echo signals to perform Rife interpolation, so that the fence effect error of the fast Fourier transform can be effectively reduced, and the distance between the target and the distance measurement target can be calculated preliminarily. And screening target interpolation points from interpolation points obtained by interpolation of Rife based on the initial distance, ensuring that the follow-up cubic spline interpolation is only fit for local points which are strongly related to the initial distance, and reducing calculation force occupation. And performing global smooth fitting on a plurality of target interpolation points through cubic spline interpolation, and eliminating noise fluctuation and systematic errors introduced by hardware nonlinearity. Substituting the initial distance into a cubic spline interpolation function to output an accurate target distance. The radar ranging is realized efficiently and accurately through double interpolation of local fine Rife interpolation and global optimized cubic spline interpolation. In an alternative embodiment, the target spectral line includes a peak spectral line, a left adjacent spectral line adjacent to the peak spectral line, and a right adjacent spectral line; when the amplitude of the left adjacent spectral line is greater than the amplitude of the right adjacent spectral line, the initial distance is calculated by the following formula: When the amplitude of the left adjacent spectral line is smaller than that of the right adjacent spectral line, the initial distance is calculated by the following formula: wherein distance represents an initial distance; DeltaR represents the distance grid; representing the greater of the frequencies of the left adjacent spectral line and the right adjacent spectral line; representing the smaller of the frequencies of the left adjacent line and the right adjacent line, and RES representing the frequency difference between any two adjacent interpolation points. In this embodiment, the coarse distance is corrected to an initial distance closer to the true va