An improved method for analyzing the tailing multiple echo signal model

Abstract

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. The method comprises: step one, constructing a time domain echo signal model of a pulse laser radar; step two, constructing a single echo signal model based on the time domain echo signal model; step three, constructing a multi-target spot detection model, and determining the target distance and spot ratio coefficient corresponding to each target based on the multi-target spot detection model; step four, constructing a multiple echo signal model based on the single echo signal model, as well as the spot ratio coefficient and target distance of each target. The improved tailing 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 laser radar signal processing.

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 pulse lidar signal processing, a pulse 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 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 deficiencies 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 lidar 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 lidar;

[0008] Step 2: constructing a single echo signal model based on 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 pulsed laser radar includes:

[0012] According to the time delay function, the tail function is improved to obtain the tail pulse function;

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

[0014]

[0015] Among them, 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, 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 spot ratio parameter, H d ( ) is a step function.

[0023] In at least one embodiment of the present application, in step three, constructing a multi-target light spot detection model, and determining the target distance and light spot ratio coefficient corresponding to each target according to the multi-target light spot detection model includes:

[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 actual spot area S1, S2, ..., S of 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 based on the single echo signal model, the spot ratio coefficient of each target, and the target distance. 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, f ri (φ) is the bidirectional reflectance distribution function under the incident angle corresponding to the i-th target, 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, step five is further included, performing simulation analysis based on 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 tailing 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 Schematic diagram of an improved tailing multiple echo signal model analysis method according to one embodiment of the present application;

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

[0050] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below in conjunction with the drawings in the embodiments 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 the embodiments. 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 understood 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 this application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this 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. Therefore, it should not be understood as limiting the scope of protection of this application.

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

[0053] This application provides an improved tailing multiple echo signal model analysis method, such as Figure 1 As shown, the following steps are included:

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

[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 process:

[0059] According to the time delay function, the tail function is improved to obtain the tail 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] Among them, 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 actual pulse having a steep rising edge and a slow falling edge, 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 pulse lidar's echo is performed by replacing the traditional Gaussian pulse waveform with the improved tailing pulse waveform.

[0067] In the improved tailed multiple echo signal model analysis method of the present application, in step 2, a single echo signal model is constructed based on the time domain echo signal model. 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, 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 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 lidar, and the echo characteristics of the pulse lidar are described by a power equation. This 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 based on the assumption that the entire spot detection is located in a single expansion plane. However, in actual applications, there are multiple expansion planes, each located in a different position.

[0073] Therefore, in a preferred embodiment of the present application, 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 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 actual spot area S1, S2, ..., S of 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, taking two targets as an example, assuming that target 2 is fixed and target 1 can move in the up and down and forward and backward directions. 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] Get the actual spot areas S1 and S2 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] Moreover, 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 way and used as the 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 based on the single echo signal model, the spot ratio coefficient of each target, and the target distance. 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, f ri (φ) is the bidirectional reflectance distribution function under the incident angle corresponding to the i-th target, 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 tailing 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, a single echo scenario is simulated; when the number of targets is greater than 1, a multiple echo scenario is simulated.

[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 between the pulse waveforms will also cause deformation, that is, the appearance of multiple echo signals. Therefore, by obtaining a multiple echo signal model with an improved tail pulse waveform, the echo signals of different numbers of targets can be simulated by setting different n values. By correspondingly changing the spot ratio coefficient and the size of the target distance, the overlapping of different multiple echo signals can be simulated, so that a more accurate simulation analysis of the real environment can be performed and more realistic simulation data can be obtained. On the basis of the simulation analysis, the corresponding theoretical analysis can be carried out in combination with the multiple echo situation, and the echo decomposition strategy can be further combined to extract 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 beginning and slow at the end, 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 degrees of overlap, 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, the appearance of multiple echo signals. By performing corresponding theoretical analysis of 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 description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection 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 lidar; Step 2: constructing a single echo signal model based on 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, the time domain echo signal model of the pulse lidar is constructed, including: According to the time delay function, the tail function is improved to obtain the tail pulse function; The time domain echo signal model of the pulse laser radar is constructed by the tail pulse function. The time domain echo signal model is: Among them, 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 based on the time domain echo signal model. 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, 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 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 actual spot area S1, S2, ..., S of 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 based on 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, f ri (φ) is the bidirectional reflectance distribution function under the incident angle corresponding to the i-th target, 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 based on the multiple echo signal model. When the number of targets is 1, a single echo scenario is simulated; when the number of targets is greater than 1, a multiple echo scenario is simulated.

8. The improved tailing multiple echo signal model analysis method according to claim 7, characterized in that: 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.

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