Multi-echo signal model analysis method for improving trailing

Abstract

The invention belongs to the technical field of radar signal processing, and particularly relates to a multi-time echo signal model analysis method for improving trailing. The method comprises the following steps: step 1, constructing a time domain echo signal model of the pulse laser radar; 2, constructing a single echo signal model according to the time domain echo signal model; 3, constructing a multi-target light spot detection model, and determining a target distance and a light spot proportionality coefficient corresponding to each target according to the multi-target light spot detection model; and 4, according to the single-time echo signal model, and the light spot proportionality coefficient and the target distance of each target, constructing a multi-time echo signal model. According to the multi-time echo signal model analysis method for improving trailing, the multi-time echo signal model is analyzed, a technical basis can be provided for extracting echo information of multiple targets, and the problems of information loss and low ranging precision in pulse laser radar signal processing can be solved.

Description

Technical Field

[0001] The present application belongs to the field of radar signal processing technology, and in particular relates to an improved tailing multiple echo signal model analysis method. Background Art

[0002] At present, the research on multiple echo signal processing is mainly focused on the surveying and measurement of lidar systems. In the processing of pulsed lidar signals, a pulsed laser spot usually contains multiple echo pulse signals. The current processing method mainly includes two aspects. On the one hand, the echo signal is regarded as a single echo. This processing method leads to a large ranging error when the spot is irradiated on multiple targets, especially in the application of large-footprint lidar, which faces the situation of different degrees of overlap of multiple echo signals; on the other hand, the Gaussian model is usually used for multiple echo decomposition and analysis, but the actual pulse is not a standard Gaussian model, which leads to a large fitting error with the actual pulse echo waveform, resulting in information loss and low ranging accuracy.

[0003] Therefore, it is desired to have a technical solution to overcome or at least alleviate at least one of the above-mentioned defects of the prior art. Summary of the invention

[0004] The purpose of this application is to provide an improved tailing multiple echo signal model analysis method to solve the problem that the existing pulse laser radar model does not accurately characterize the actual pulse echo.

[0005] The technical solution of this application is:

[0006] An improved tailing multiple echo signal model analysis method, comprising:

[0007] Step 1: Construct a time domain echo signal model of the pulse laser radar;

[0008] Step 2: constructing a single echo signal model according to the time domain echo signal model;

[0009] Step 3: construct a multi-target light spot detection model, and determine the target distance and light spot ratio coefficient corresponding to each target according to the multi-target light spot detection model;

[0010] Step 4: construct a multiple echo signal model based on the single echo signal model, the spot ratio coefficient of each target and the target distance.

[0011] In at least one embodiment of the present application, in step 1, constructing a time domain echo signal model of a pulse laser radar includes:

[0012] The tailing function is improved according to the time delay function to obtain the tailing pulse function;

[0013] The time domain echo signal model of the pulse laser radar is constructed by the tail pulse function, and the time domain echo signal model is:

[0014]

[0015] Where, f is the time domain echo signal, η n is the atmospheric attenuation coefficient, P r ( ) is the echo signal power, t is the current time, t d is the time corresponding to the target distance, τ is the transmission pulse width, H d ( ) is a step function.

[0016] In at least one embodiment of the present application, the step function is:

[0017]

[0018] Among them, e is the adjustment parameter.

[0019] In at least one embodiment of the present application, in step 2, a single echo signal model is constructed according to the time domain echo signal model, and the single echo signal model is:

[0020]

[0021]

[0022] Among them, P r ( ) is the echo signal power, At is the echo intensity, t is the current time, R is the target distance, c is the speed of light, τ is the transmit pulse width, w is the beam waist radius, φ is the incident angle, P0 is the initial transmit power, D is the optical aperture of the receiving system, and f r (φ) is the bidirectional reflectance distribution function at the corresponding incident angle, η atm is the one-way atmospheric permeability coefficient, η sys is the optical transmittance of the system, k is the light spot ratio parameter, H d ( ) is a step function.

[0023] In at least one embodiment of the present application, in step three, a multi-target spot detection model is constructed, and a target distance and a spot ratio coefficient corresponding to each target are determined according to the multi-target spot detection model, including:

[0024] Arrange multiple targets within the detection range of the pulse laser radar;

[0025] Get the target distance R1, R2, R between the pulse laser radar and each target n ;

[0026] Calculate the spot area of ​​each target at the corresponding target distance:

[0027]

[0028]

[0029] …

[0030]

[0031] in, is the divergence angle, n is the number of targets;

[0032] Get the spot area S1, S2, ..., S actually irradiated on each target n ;

[0033] Calculate the spot ratio coefficient corresponding to each target:

[0034] k1=S1 / S'1

[0035] k2=S2 / S'2

[0036] …

[0037] k n =S n / S' n

[0038] in:

[0039] k1+k2+…+k n =1.

[0040] In at least one embodiment of the present application, in step 4, a multiple echo signal model is constructed according to the single echo signal model, the spot ratio coefficient of each target and the target distance, and the multiple echo signal model is:

[0041]

[0042]

[0043] Among them, P r ( ) is the echo signal power, n is the number of targets, A ti is the echo intensity corresponding to the i-th target, t is the current moment, R i is the target distance corresponding to the i-th target, c is the speed of light, τ is the transmit pulse width, w is the beam waist radius, φ is the incident angle, P0 is the initial transmit power, D is the optical aperture of the receiving system, and f ri (φ) is the bidirectional reflectance distribution function of the i-th target at the corresponding incident angle, η atm is the one-way atmospheric permeability coefficient, ηsys is the optical transmittance of the system, k i is the spot ratio parameter corresponding to the i-th target, H d ( ) is a step function.

[0044] In at least one embodiment of the present application, the method further includes step five, performing simulation analysis according to the multiple echo signal model, simulating a single echo scenario when the target number is 1, and simulating a multiple echo scenario when the target number is greater than 1.

[0045] In at least one embodiment of the present application, the method further includes step six, obtaining simulation analysis data of the multiple echo signal models, and constructing a data model library based on the simulation analysis data.

[0046] The invention has at least the following beneficial technical effects:

[0047] The improved trailing multiple echo signal model analysis method of the present application can provide a technical basis for extracting echo information of multiple targets by analyzing the multiple echo signal model, and can overcome the problems of information loss and low ranging accuracy in pulse lidar signal processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of an improved tailing multiple echo signal model analysis method according to an embodiment of the present application;

[0049] Figure 2 This is a schematic diagram of a pulse laser radar generating multiple echo signals according to an embodiment of the present application. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the embodiment of this application will be described in more detail below in conjunction with the drawings in the embodiment of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of this application, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be construed as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of this application are described in detail below in conjunction with the drawings.

[0051] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present application.

[0052] The following is combined with Figure 1 to Figure 2 This application is described in further detail.

[0053] The present application provides a method for analyzing a multiple echo signal model with improved tailing, such as Figure 1 As shown, the following steps are included:

[0054] Step 1: Construct a time domain echo signal model of the pulse laser radar;

[0055] Step 2: construct a single echo signal model based on the time domain echo signal model;

[0056] Step 3: construct a multi-target spot detection model, and determine the target distance and spot ratio coefficient corresponding to each target according to the multi-target spot detection model;

[0057] Step 4: Construct a multiple echo signal model based on the single echo signal model, the spot ratio coefficient of each target and the target distance.

[0058] The improved tailing multiple echo signal model analysis method of the present application, in step 1, constructing the time domain echo signal model of the pulse laser radar specifically includes the following processes:

[0059] The tailing function is improved according to the time delay function to obtain the tailing pulse function;

[0060] The time domain echo signal model of the pulse lidar is constructed by the tail pulse function. The time domain echo signal model is:

[0061]

[0062] Where, f is the time domain echo signal, η n is the atmospheric attenuation coefficient, P r ( ) is the echo signal power, t is the current time, t d is the time corresponding to the target distance, τ is the transmission pulse width, H d ( ) is a step function.

[0063] The step function is:

[0064]

[0065] Among them, e is an adjustment parameter, and its value is between (0, 1).

[0066] In this embodiment, taking into account the characteristics of the steep rising edge and slow falling edge of the actual pulse, the heavy-tail function is improved by the time delay function to obtain the tailing pulse function. On the basis of the tailing pulse function, a time domain model of the improved tailing pulse waveform of the pulse lidar is constructed. The time domain waveform modeling of the echo of the pulse lidar is performed by replacing the traditional Gaussian pulse waveform with the improved tailing pulse waveform.

[0067] In the improved tailing multiple echo signal model analysis method of the present application, in step 2, a single echo signal model is constructed according to the time domain echo signal model, and the single echo signal model is:

[0068]

[0069]

[0070] Among them, P r ( ) is the echo signal power, A t is the echo intensity, t is the current time, R is the target distance, c is the speed of light, τ is the transmit pulse width, w is the beam waist radius, φ is the incident angle, P0 is the initial transmit power, D is the optical aperture of the receiving system, and f r (φ) is the bidirectional reflectance distribution function at the corresponding incident angle, η atm is the one-way atmospheric permeability coefficient, η sys is the optical transmittance of the system, k is the light spot ratio parameter, H d ( ) is a step function.

[0071] In this embodiment, a single echo signal model is derived based on the time domain echo signal model of the pulse laser radar, and the echo characteristics of the pulse laser radar are described by the power equation. The equation expresses the change of the power of the laser pulse signal with distance and provides information about the echo signal strength.

[0072] The single echo signal model is established on the assumption that the entire spot detection is in a single expansion plane. However, in actual applications, there are multiple expansion planes, each located at a different position.

[0073] Therefore, in the preferred embodiment of the present application, in step 3, a multi-target spot detection model is constructed, and the target distance and spot ratio coefficient corresponding to each target are determined according to the multi-target spot detection model, including the following process:

[0074] Arrange multiple targets within the detection range of the pulse laser radar;

[0075] Get the target distance R1, R2, R between the pulse laser radar and each target n ;

[0076] Calculate the spot area of ​​each target at the corresponding target distance:

[0077]

[0078]

[0079]

[0080]

[0081] in, is the divergence angle, n is the number of targets;

[0082] Get the spot area S1, S2, ..., S actually irradiated on each target n ;

[0083] Calculate the spot ratio coefficient corresponding to each target:

[0084] k1=S1 / S'1

[0085] k2=S2 / S'2

[0086] …

[0087] k n =S n / S' n

[0088] in:

[0089] k1+k2+…+k n =1.

[0090] In one embodiment of the present application, Figure 2 As shown in the figure, take two targets as an example, assuming that target 2 is fixed and target 1 can move up and down and forward and backward. As can be seen from the figure, the target distance between the pulse laser radar and target 1 is R1, and the distance between the pulse laser radar and target 2 is R2. Therefore, the corresponding spot area at each target distance is calculated as:

[0091]

[0092]

[0093] Obtain the spot areas S1 and S2 actually irradiated on target 1 and target 2;

[0094] The ratio of the spot area irradiated on target 1 and target 2 to the spot area corresponding to the respective target distances is the spot ratio coefficient:

[0095] k1=S1 / S'1

[0096] k2=S2 / S'2

[0097] And, k1+k2=1.

[0098] The spot ratio coefficient and target distance of each target in the multiple echo signal processing scenario are calculated in the above manner and used as input conditions for constructing the multiple echo signal model.

[0099] In the improved tailing multiple echo signal model analysis method of the present application, in step 4, a multiple echo signal model is constructed according to the single echo signal model, the spot ratio coefficient of each target and the target distance, and the obtained multiple echo signal model is:

[0100]

[0101]

[0102] Among them, P r ( ) is the echo signal power, n is the number of targets, A ti is the echo intensity corresponding to the i-th target, t is the current moment, R i is the target distance corresponding to the i-th target, c is the speed of light, τ is the transmit pulse width, w is the beam waist radius, φ is the incident angle, P0 is the initial transmit power, D is the optical aperture of the receiving system, and f ri (φ) is the bidirectional reflectance distribution function of the i-th target at the corresponding incident angle, η atm is the one-way atmospheric permeability coefficient, η sys is the optical transmittance of the system, k i is the spot ratio parameter corresponding to the i-th target, H d () is a step function.

[0103] The improved trailing multiple echo signal model analysis method of the present application also includes step five, performing simulation analysis based on the multiple echo signal model, when the number of targets is 1, simulating a single echo scenario; when the number of targets is greater than 1, simulating a multiple echo scenario.

[0104] In actual environments, due to the different targets and the energy attenuation during the transmission process, the echo signal may be deformed. According to the multiple echo signal model, when there are multiple targets in the pulse spot, the superposition of the pulse waveforms will also cause deformation, that is, multiple echo signals appear. Therefore, by obtaining the multiple echo signal model of the improved trailing pulse waveform, the echo signals of different numbers of targets can be simulated by setting different n values, and the overlap of different multiple echo signals can be simulated by correspondingly changing the spot ratio coefficient and the size of the target distance, so as to make it possible to perform more accurate simulation analysis on the real environment and obtain more realistic simulation data. On the basis of the simulation analysis, the corresponding theoretical analysis can be combined with the multiple echo situations, and the echo decomposition strategy can be further combined to extract the target information and reduce the ranging error caused by deformation.

[0105] The improved tailing multiple echo signal model analysis method of the present application also includes step six, obtaining multiple echo signal model simulation analysis data, and constructing a data model library based on the simulation analysis data, which can be used as a training model library for methods such as neural networks and deep learning.

[0106] The improved tailing multiple echo signal model analysis method of the present application, by establishing a tailing model of multiple echoes to model the actual echo pulse that is steep at the front and slow at the back, can make up for the problem of low fitting and correlation of Gaussian pulses in characterizing echo pulses. And by being able to perform simulation analysis on the established model, by changing the spot ratio coefficient and the target distance to characterize multiple echo signals with different overlapping degrees, a multiple echo signal model is constructed. According to the multiple echo signal model, when there are multiple targets in the pulse spot, the superposition between the pulse waveforms will also cause deformation, that is, multiple echo signals appear. By performing corresponding theoretical analysis on the multiple echo situation through the multiple echo signal model, it is possible to extract target information and reduce the ranging error caused by deformation, providing theoretical support for overcoming the problems of information loss and low ranging accuracy in multiple echo signals.

[0107] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. An improved tailing multiple echo signal model analysis method, characterized in that: include: Step 1: Construct a time domain echo signal model of the pulse laser radar; Step 2: constructing a single echo signal model according to the time domain echo signal model; Step 3: construct a multi-target light spot detection model, and determine the target distance and light spot ratio coefficient corresponding to each target according to the multi-target light spot detection model; Step 4: construct a multiple echo signal model based on the single echo signal model, the spot ratio coefficient of each target and the target distance.

2. The improved tailing multiple echo signal model analysis method according to claim 1, characterized in that: In step 1, a time domain echo signal model of the pulsed lidar is constructed, including: The tailing function is improved according to the time delay function to obtain the tailing pulse function; The time domain echo signal model of the pulse laser radar is constructed by the tail pulse function, and the time domain echo signal model is: Where, f is the time domain echo signal, η n is the atmospheric attenuation coefficient, P r () is the echo signal power, t is the current time, t d is the time corresponding to the target distance, τ is the transmission pulse width, H d () is a step function.

3. The improved tailing multiple echo signal model analysis method according to claim 2, characterized in that: The step function is: Among them, e is the adjustment parameter.

4. The improved tailing multiple echo signal model analysis method according to claim 3, characterized in that: In step 2, a single echo signal model is constructed according to the time domain echo signal model, and the single echo signal model is: Among them, P r () is the echo signal power, A t is the echo intensity, t is the current time, R is the target distance, c is the speed of light, τ is the transmit pulse width, w is the beam waist radius, φ is the incident angle, P0 is the initial transmit power, D is the optical aperture of the receiving system, and f r (φ) is the bidirectional reflectance distribution function at the corresponding incident angle, η atm is the one-way atmospheric permeability coefficient, η sys is the optical transmittance of the system, k is the light spot ratio parameter, H d () is a step function.

5. The improved tailing multiple echo signal model analysis method according to claim 4, characterized in that: In step three, a multi-target spot detection model is constructed, and the target distance and spot ratio coefficient corresponding to each target are determined according to the multi-target spot detection model, including: Arrange multiple targets within the detection range of the pulse laser radar; Get the target distance R1, R2, R between the pulse laser radar and each target n ; Calculate the spot area of ​​each target at the corresponding target distance: in, is the divergence angle, n is the number of targets; Get the spot area S1, S2, ..., S actually irradiated on each target n ; Calculate the spot ratio coefficient corresponding to each target: k1=S1 / S'1 k2=S2 / S'2 … k n =S n / S’ n in: k1+k2+…+k n =1。 6. The improved tailing multiple echo signal model analysis method according to claim 5, characterized in that: In step 4, a multiple echo signal model is constructed according to the single echo signal model, the spot ratio coefficient of each target and the target distance. The multiple echo signal model is: Among them, P r () is the echo signal power, n is the number of targets, A ti is the echo intensity corresponding to the i-th target, t is the current moment, R i is the target distance corresponding to the i-th target, c is the speed of light, τ is the transmit pulse width, w is the beam waist radius, φ is the incident angle, P0 is the initial transmit power, D is the optical aperture of the receiving system, and f ri (φ) is the bidirectional reflectance distribution function of the i-th target at the corresponding incident angle, η atm is the one-way atmospheric permeability coefficient, η sys is the optical transmittance of the system, k i is the spot ratio parameter corresponding to the i-th target, H d () is a step function.

7. The improved tailing multiple echo signal model analysis method according to claim 6, characterized in that: The method further includes step 5 of performing simulation analysis according to the multiple echo signal model, simulating a single echo scenario when the number of targets is 1, and simulating a multiple echo scenario when the number of targets is greater than 1.

8. The improved tailing multiple echo signal model analysis method according to claim 7, characterized in that: The method also includes step six, obtaining simulation analysis data of the multiple echo signal models, and constructing a data model library based on the simulation analysis data.

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