Attitude correction method and system for space-based Rayleigh laser radar signal and storage medium

Abstract

The invention discloses a space-based Rayleigh laser radar signal attitude correction method and system, and a storage medium. The method comprises the steps of obtaining a photon number profile at each moment and attitude data at the corresponding moment; abnormal attitude data and corresponding photon number profiles are detected and eliminated; an average deflection angle is generated according to the screened attitude data, and the actual altitude is calculated; and generating a corrected temperature profile based on the screened photon number profile and the actual altitude. According to the technical scheme, from the perspective of signal processing, an efficient and low-cost attitude correction tool is provided for scholars in related fields for solving the problem that inversion deviation is generated due to platform attitude change in the space-based Rayleigh laser radar measurement process, inversion deviation caused by laser beam pointing instability is reduced, and the precision of the space-based Rayleigh laser radar is improved. Therefore, a high-precision temperature inversion profile can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of laser radar for atmospheric environment detection, and in particular to attitude correction of an airborne Rayleigh laser radar for middle and upper atmospheric detection. Background Art

[0002] Rayleigh LiDAR is mainly used to measure atmospheric temperature, molecular density and atmospheric fluctuations at altitudes above 30km. Its measurement data has important applications in communications, meteorology and other fields. The measurement principle of Rayleigh LiDAR is that atmospheric aerosols above 30km are considered negligible, so the atmospheric elastic scattering echo signal above 30km is mainly Rayleigh scattering of atmospheric molecules. Using the Rayleigh scattering echo signal of atmospheric molecules, the relevant parameters of the middle and high-level atmosphere can be inverted. Since the airborne Rayleigh LiDAR measurement platform can effectively shorten the distance between the LiDAR and the detected object, reduce the attenuation of the laser beam and its backscattered signal, greatly reduce the laser power and the aperture of the receiving telescope, and thus reduce the complexity and cost of the system. Therefore, compared with ground-based LiDAR equipment of the same size, the airborne Rayleigh LiDAR can obtain better data quality. However, due to the complex dynamic interference in the atmosphere, the airborne measurement platform will fluctuate during the observation process, resulting in unstable laser beam direction. Some scholars have studied the use of attitude control systems on the measurement platform to control the change in the direction of the laser beam. This method is not only time-consuming and labor-intensive, but can only control the relative stability of the platform and cannot prevent small attitude changes of the measurement platform. For airborne Rayleigh lidar, these small attitude changes will still change the atmospheric density along the laser beam transmission path, causing large deviations in the temperature inversion results.

[0003] Therefore, it is necessary to propose an efficient posture correction method and system from the aspect of signal processing. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a method, system and storage medium for attitude correction of airborne Rayleigh lidar signals.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A method for attitude correction of an airborne Rayleigh laser radar signal, comprising:

[0007] S1. Obtaining the photon number profile at each moment and the attitude data at the corresponding moment, the attitude data including: the pitch angle and roll angle data recorded in real time by the inertial navigation system mounted on the measurement platform;

[0008] S2. Detect and remove abnormal posture data and corresponding photon number profiles; specifically including:

[0009] (201) Setting the rejection threshold and angle threshold;

[0010] (202) Abnormal data are eliminated by using the interquartile range of the Euclidean distance between the measured value and the approximate value of the pitch angle to obtain the first screening measured data;

[0011] (203) The interquartile range of the Euclidean distance between the measured value and the approximate value of the rolling angle is used to eliminate abnormal data and obtain the second screening measured data;

[0012] (204) repeating step (201) for the second screening measured data to obtain the third screening measured data;

[0013] (205) repeating step (202) for the third screening measured data to obtain the fourth screening measured data;

[0014] (206) using the rejection threshold and the angle threshold to discriminate the filtered posture data to obtain the final filtered measured data;

[0015] S3. Generate an average deflection angle based on the filtered posture data and calculate the actual altitude; specifically including:

[0016] (301) constructing a carrier coordinate system;

[0017] (302) establishing a relationship model between detection distance and actual altitude based on the carrier coordinate system;

[0018] (303) calculating the average pitch angle and the average roll angle in the filtered measured data, and substituting them into the relationship model to obtain the actual altitude;

[0019] S4. Generate a corrected temperature profile based on the filtered photon number profile and the actual altitude.

[0020] Furthermore, the approximate value of the pitch angle is the sum of the average value of the pitch angle data and the jitter amount at each moment, and the approximate value of the roll angle is the sum of the average value of the roll angle data and the jitter amount at each moment.

[0021] Furthermore, the jitter amount at each moment is defined as the difference between the posture angle at the next moment and the posture angle at the previous moment of the posture data.

[0022] Furthermore, the step (302) of establishing a relationship model between the detection distance and the actual altitude includes: establishing a spatial position relationship between the carrier coordinate system and the geographic coordinate system; and constructing a spatial relative relationship between the laser beam emission direction and the carrier coordinate system.

[0023] Furthermore, establishing the spatial position relationship of the carrier coordinate system relative to the geographic coordinate system includes: constructing a rotation matrix including a pitch angle and a roll angle for transforming from the carrier coordinate system to the geographic coordinate system.

[0024] Furthermore, the spatial relative relationship between the laser beam emission direction and the carrier coordinate system is constructed, including establishing a polar coordinate system on the carrier coordinate system, describing the laser beam emission direction with the zenith angle and azimuth angle in the polar coordinate system, and describing the detection distance with the polar diameter in the polar coordinate system.

[0025] The present invention also provides an attitude correction system for an airborne Rayleigh laser radar signal, comprising:

[0026] An acquisition module is used to acquire the photon number profile at each moment and the attitude data at the corresponding moment, wherein the attitude data includes: pitch angle and roll angle data recorded in real time by an inertial navigation system mounted on the measurement platform;

[0027] A processing module, used to detect and remove abnormal posture data and corresponding photon number profiles;

[0028] A calculation module, used to generate an average deflection angle based on the filtered posture data and calculate the actual altitude;

[0029] Generation module: Generates the corrected temperature profile based on the filtered photon number profile and the actual altitude;

[0030] The processing module is also used to set a rejection threshold and an angle threshold, and use the interquartile range of the Euclidean distance between the measured value and the approximate value of the pitch angle and the roll angle to perform four abnormal data rejections; use the rejection threshold and the angle threshold to judge the filtered posture data to obtain the final filtered measured data;

[0031] The calculation module is also used to construct a carrier coordinate system; establish a relationship model between the detection distance and the actual altitude; calculate the average pitch angle and the average roll angle in the screened measured data, and substitute them into the relationship model to obtain the actual altitude.

[0032] Furthermore, the processing module is also used to define the difference between the attitude angle of the next moment and the attitude angle of the previous moment as the jitter amount, calculate the sum of the average value of the pitch angle data and the jitter amount as the approximate value of the pitch angle, and calculate the sum of the average value of the roll angle data and the jitter amount as the approximate value of the roll angle.

[0033] Furthermore, the calculation module is also used to construct a rotation matrix including pitch angle and roll angle for transforming from the carrier coordinate system to the geographic coordinate system, so as to establish the spatial position relationship between the carrier coordinate system and the geographic coordinate system; a polar coordinate system is established on the carrier coordinate system, and the zenith angle and azimuth angle in the polar coordinate system are used to describe the laser beam emission direction, and the polar diameter in the polar coordinate system is used to describe the detection distance, so as to construct the spatial relative relationship between the laser beam emission direction and the carrier coordinate system.

[0034] Furthermore, when the computer program is executed by a processor, the steps of the attitude correction method of the airborne Rayleigh lidar signal as described in any one of claims 1 to 6 are implemented.

[0035] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0036] 1. Improve the accuracy of temperature inversion: By accurately correcting the platform's posture changes, the impact of laser beam pointing deviation on the temperature inversion results can be significantly reduced, thereby obtaining a higher-precision temperature profile and solving the measurement error problem that cannot be completely eliminated by traditional posture control methods.

[0037] 2. Improve system stability and adaptability: The present invention effectively reduces the impact of dynamic interference on the echo signal through multiple abnormal data elimination and attitude average deviation angle calculation, ensures the stable operation of the system in complex flight environments, and improves the adaptability of airborne Rayleigh lidar under different atmospheric conditions.

[0038] 3. Reduce costs and complexity: Compared with relying on high-precision attitude control hardware, the present invention adopts signal processing to perform attitude correction, without adding additional hardware costs, reducing system complexity, and simplifying platform equipment configuration, which is highly economical and practical.

[0039] 4. Efficient data processing method: By using the Euclidean distance of the pitch angle and roll angle data to eliminate abnormal data multiple times, and combining it with the calculation of the jitter amount, the attitude correction method proposed in the present invention can effectively improve the correction efficiency, reduce the complexity of data processing, and is suitable for real-time application scenarios.

[0040] 5. Broad application prospects: The attitude correction method and system provided by the present invention are not only applicable to various application scenarios of air-based Rayleigh LiDAR, but also applicable to the detection of Rayleigh LiDAR carried on other floating platforms such as ships, promoting the diversity of LiDAR-carrying platforms and promoting the application and development of Rayleigh LiDAR technology in the fields of atmospheric detection, meteorological research, and environmental monitoring.

[0041] In summary, the present invention not only solves the attitude control problem in the prior art with a low-cost and high-efficiency data processing method, but also improves the adaptability of airborne Rayleigh lidar under different atmospheric conditions. It has important practical application value and broad promotion prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a flow chart of a method for correcting an attitude of an airborne Rayleigh laser radar signal according to the present invention;

[0043] Figure 2 Flow chart for abnormal posture data detection and elimination;

[0044] Figure 3a and Figure 3b The influence of attitude correction on temperature inversion results is shown as an example; Figure 3a The temperature inversion results before attitude correction are compared with the NRLMSISE-00 model; Figure 3b The comparison chart of the temperature inversion result after attitude correction and the NRLMSISE-00 model;

[0045] Figure 4 It is a module diagram of the airborne Rayleigh lidar signal attitude correction system according to the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other arbitrarily without conflict.

[0047] The embodiment of the present invention provides a method for correcting the attitude of an airborne Rayleigh laser radar signal. Figure 1 As shown, the method includes:

[0048] Step 101, obtaining the photon number profile at each moment and the attitude data at the corresponding moment;

[0049] Step 102, detecting and eliminating abnormal posture data and corresponding photon number profiles;

[0050] Step 103, generating an average deflection angle according to the filtered posture data, and calculating the actual altitude;

[0051] Step 104 : generating a corrected temperature profile based on the screened photon number profile and the actual altitude.

[0052] In this embodiment, the photon number profile in step 101 is the Rayleigh laser radar echo signal, and each echo signal is separated by a distance resolution, and the number of photons detected at each distance resolution is recorded. The attitude data is the pitch angle and roll angle data recorded by the inertial navigation system carried on the measurement platform at intervals of one second.

[0053] In actual measurements, the change in the platform attitude shows a pattern of deviation from the fixed launch angle over a period of time, and is accompanied by slight jitter on the basis of this deviation. Based on this pattern, an attitude correction method based on average deflection can be designed. The average value of the acquired pitch angle data and the average value of the roll angle data are defined as the average deflection, and the difference between the attitude data at the next moment and the attitude data at the previous moment is the jitter. Based on the law of platform attitude change, when the operation of the measurement platform is relatively stable during the selected time period, the platform attitude data can be approximately represented by the sum of the average deflection and the jitter. Since the absolute stability of the measurement platform does not exist in actual measurements, it is necessary to consider eliminating abnormal data, which is mainly reflected in the excessive change in attitude between the previous and next moments, that is, data with obvious jitter. Figure 2 The example demonstrates the process of detecting and removing abnormal posture data and corresponding photon number profiles, which includes:

[0054] Step 201, setting a rejection threshold and an angle threshold;

[0055] Step 202, using the interquartile range of the Euclidean distance between the actual pitch angle measurement value and the approximate value to eliminate abnormal data, to obtain the first screening actual measured data;

[0056] Step 203, using the interquartile range of the Euclidean distance between the actual rolling angle value and the approximate value to eliminate abnormal data, to obtain the second screening actual rolling angle data;

[0057] Step 204, repeating step 201 for the second screening measured data to obtain the third screening measured data;

[0058] Step 205, repeating step 202 for the third screening measured data to obtain the fourth screening measured data;

[0059] Step 206, determine whether the rejection amount is less than the rejection amount threshold, and whether the difference between the maximum and minimum values ​​of the filtered posture data is less than the angle threshold. If both are satisfied, the final filtered measured data is obtained, otherwise the posture data and the corresponding photon number profile will be reselected.

[0060] Specifically, the rejection threshold in step 201 can filter out the stage where the platform is running more stably and control the amount of data. When the platform is in a state of rapid fluctuation, the amount of data will be greatly reduced after abnormal elimination. Therefore, this embodiment sets the rejection threshold to one-sixth of the posture data. When the rejection amount is greater than this threshold, it is considered that the platform fluctuates violently at this stage, and the acquired data is of little use value and should be filtered. Considering that the interval between the maximum and minimum values ​​of the posture data is too large, which will affect the posture correction effect, the angle threshold is set to 1° to control the posture data quality after the abnormal data is eliminated.

[0061] Steps 202-205 are to use the quartile method to perform four abnormal eliminations on the posture data. For abnormal posture data, the jitter is too large, which leads to a significant difference between the approximate value and the measured value. Therefore, the interquartile range of the Euclidean distance between the approximate value and the measured value is used as the elimination standard. It is found through observation that after four abnormal eliminations, there is no obvious abnormal data. At this time, it is believed that the actual observation angle can be approximately expressed by the sum of the average deflection angle and the jitter amount. Furthermore, since the abnormal data with excessive jitter has been eliminated, the jitter amount of the screened data is approximately negligible. Therefore, the average deflection angle can be further used to replace the measured posture data for steps 103 and 104.

[0062] The following is the pseudo code for detecting and removing abnormal posture data and the corresponding photon number profile process:

[0063]

[0064]

[0065] In this embodiment, to obtain the actual altitude in step 103, it is necessary to establish a coordinate system that describes the position of the laser radar system and the direction of the laser beam emission. Since the laser radar is carried on an air-based measurement platform, it is necessary to first construct a carrier coordinate system (ox b y b z b ), whose origin coincides with the center of gravity of the carrier, and the ox b The axis is positive to the right along the horizontal axis of the carrier, oy b The axis is positive along the longitudinal axis of the carrier, oz b The axis is perpendicular to the longitudinal axis of the carrier and is positive upward.

[0066] Based on the rotation matrix containing the pitch angle θ and the roll angle γ The carrier coordinate system and the geographic coordinate system (ox g y g z g )’s spatial relationship:

[0067]

[0068] Considering the emission direction of the laser beam, a polar coordinate system is established on the carrier coordinate system. The zenith angle θ0 and azimuth angle α in the polar coordinate system are used to describe the emission direction of the laser beam, and the polar radius R in the polar coordinate system is used to describe the detection distance, as shown in formula (3):

[0069]

[0070] By combining formula (2) and formula (3), a relationship model between the detection distance R and the actual altitude z can be established;

[0071] z=z g =Rcosθcosγcosθ0-Rcosθsinγsinθ0sinα+Rsinθsinθ0cosα, (4)

[0072] Substitute the average deflection angle obtained in step 102 into θ and γ in formula (4), and combine the actual detection distance R, the actual laser beam emission direction θ0 and α to obtain the actual altitude.

[0073] In this embodiment, the corrected temperature profile generated in step 104 can be calculated by formula (5):

[0074]

[0075] Where g is the acceleration due to gravity, R d is the gas constant of dry air, z is the actual altitude obtained in step 103, and T(z) is the atmospheric temperature at altitude z. ρ(z) is the atmospheric density at altitude z, which is calculated from the filtered photon number profile obtained in step 102. Z0 is the reference altitude, which is generally the top of the detection signal. ρ Z0 and T Z0 are the atmospheric density and atmospheric temperature at the reference altitude, respectively. Figure 3a and Figure 3b The effect of the attitude correction method of the airborne Rayleigh lidar signal proposed in the present invention is demonstrated by example, and the results show that the inversion deviation can be effectively reduced by the attitude correction method, and the inversion result is more consistent with the atmospheric standard model.

[0076] Preferably, an embodiment of the present invention further provides a module diagram of an attitude correction system for an airborne Rayleigh laser radar signal, such as Figure 4 As shown, the system includes:

[0077] The acquisition module 401 is used to acquire the photon number profile at each moment and the attitude data at the corresponding moment, wherein the attitude data includes: the pitch angle and roll angle data recorded by the inertial navigation system carried on the measurement platform;

[0078] Processing module 402, used to detect and remove abnormal posture data and corresponding photon number profiles;

[0079] A calculation module 403 generates an average deflection angle according to the filtered posture data and calculates the actual altitude;

[0080] The generating module 404 generates a corrected temperature profile based on the filtered photon number profile and the actual altitude.

[0081] Specifically, the processing module 402 is also used to set a rejection threshold and an angle threshold; use the interquartile range of the Euclidean distance between the measured values ​​and the approximate values ​​of the pitch angle and roll angle to perform four abnormal data rejections; use the rejection threshold and the angle threshold to judge the filtered posture data to obtain the final filtered measured data.

[0082] The processing module 402 is also used to define the difference between the attitude angle of the next moment and the attitude angle of the previous moment of the measured data as the jitter amount. The average value of the pitch angle data and the sum of the jitter amount are calculated as the approximate value of the pitch angle, and the average value of the roll angle data and the sum of the jitter amount are calculated as the approximate value of the roll angle.

[0083] The calculation module 403 is also used to construct a carrier coordinate system; establish a relationship model between the detection distance and the actual altitude; substitute the average values ​​of the pitch angle and the roll angle generated according to the filtered attitude data into the relationship model to obtain the actual altitude.

[0084] The calculation module 403 is also used to construct a rotation matrix including pitch angle and roll angle for transforming from the carrier coordinate system to the geographic coordinate system, so as to establish the spatial position relationship between the carrier coordinate system and the geographic coordinate system; a polar coordinate system is established on the carrier coordinate system, and the zenith angle and azimuth angle in the polar coordinate system are used to describe the laser beam emission direction, and the polar diameter in the polar coordinate system is used to describe the detection distance, so as to construct the spatial relative relationship between the laser beam emission direction and the carrier coordinate system.

[0085] The present invention proposes a method and system for attitude correction of airborne Rayleigh lidar signals. In view of the problem that the platform attitude change during the airborne Rayleigh lidar measurement process is difficult to completely overcome by hardware control alone and will cause deviations in subsequent inversion, the attitude correction of the echo signal is achieved from the perspective of signal processing, providing scholars in related fields with an efficient and low-cost attitude correction tool, promoting the progress of related technologies, and at the same time, the technical solution of the present invention also reduces the inversion deviation caused by the instability of laser beam pointing and improves the temperature inversion accuracy.

[0086] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those of ordinary skill in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0087] The present invention is not limited to the embodiments described above. The above description of the specific embodiments is intended to describe and illustrate the technical solution of the present invention. The above specific embodiments are merely illustrative and not restrictive. Without departing from the scope of the present invention and the scope of protection of the claims, a person of ordinary skill in the art can also make many forms of specific changes under the guidance of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A method for attitude correction of airborne Rayleigh laser radar signals, characterized in that: include: S1. Obtaining the photon number profile at each moment and the attitude data at the corresponding moment, the attitude data including: the pitch angle and roll angle data recorded in real time by the inertial navigation system mounted on the measurement platform; S2. Detect and remove abnormal posture data and corresponding photon number profiles; specifically including: (201) Setting the rejection threshold and angle threshold; (202) Abnormal data are eliminated by using the interquartile range of the Euclidean distance between the measured value and the approximate value of the pitch angle to obtain the first screening measured data; (203) The interquartile range of the Euclidean distance between the measured value and the approximate value of the rolling angle is used to eliminate abnormal data and obtain the second screening measured data; (204) repeating step (201) for the second screening measured data to obtain the third screening measured data; (205) repeating step (202) for the third screening measured data to obtain the fourth screening measured data; (206) using the rejection threshold and the angle threshold to discriminate the filtered posture data to obtain the final filtered measured data; S3. Generate an average deflection angle based on the filtered posture data and calculate the actual altitude; specifically including: (301) constructing a carrier coordinate system; (302) establishing a relationship model between detection distance and actual altitude based on the carrier coordinate system; (303) calculating the average pitch angle and the average roll angle in the filtered measured data, and substituting them into the relationship model to obtain the actual altitude; S4. Generate a corrected temperature profile based on the filtered photon number profile and the actual altitude.

2. The method for attitude correction of airborne Rayleigh laser radar signals according to claim 1, characterized in that: The approximate value of the pitch angle is the sum of the average value of the pitch angle data and the jitter amount at each moment, and the approximate value of the roll angle is the sum of the average value of the roll angle data and the jitter amount at each moment.

3. The method for attitude correction of airborne Rayleigh laser radar signals according to claim 2, characterized in that: The jitter amount at each moment is defined as the difference between the posture angle at the next moment and the posture angle at the previous moment of the posture data.

4. The method for attitude correction of airborne Rayleigh laser radar signals according to claim 1, characterized in that: The step (302) of establishing a relationship model between the detection distance and the actual altitude includes: establishing a spatial position relationship between the carrier coordinate system and the geographic coordinate system; and constructing a spatial relative relationship between the laser beam emission direction and the carrier coordinate system.

5. The method for attitude correction of airborne Rayleigh laser radar signals according to claim 4, characterized in that: Establishing the spatial position relationship of the carrier coordinate system relative to the geographic coordinate system includes: constructing a rotation matrix including a pitch angle and a roll angle for transforming from the carrier coordinate system to the geographic coordinate system.

6. The method for attitude correction of airborne Rayleigh laser radar signals according to claim 4, characterized in that: Constructing the spatial relative relationship between the laser beam emission direction and the carrier coordinate system includes establishing a polar coordinate system on the carrier coordinate system, describing the laser beam emission direction with the zenith angle and azimuth angle in the polar coordinate system, and describing the detection distance with the polar diameter in the polar coordinate system.

7. An attitude correction system for airborne Rayleigh laser radar signals, characterized in that: include: An acquisition module is used to acquire the photon number profile at each moment and the attitude data at the corresponding moment, wherein the attitude data includes: pitch angle and roll angle data recorded in real time by an inertial navigation system mounted on the measurement platform; A processing module, used to detect and remove abnormal posture data and corresponding photon number profiles; A calculation module, used to generate an average deflection angle based on the filtered posture data and calculate the actual altitude; Generation module: Generates the corrected temperature profile based on the filtered photon number profile and the actual altitude; The processing module is also used to set a rejection threshold and an angle threshold, and use the interquartile range of the Euclidean distance between the measured value and the approximate value of the pitch angle and the roll angle to perform four abnormal data rejections; use the rejection threshold and the angle threshold to judge the filtered posture data to obtain the final filtered measured data; The calculation module is also used to construct a carrier coordinate system; establish a relationship model between the detection distance and the actual altitude; calculate the average pitch angle and the average roll angle in the screened measured data, and substitute them into the relationship model to obtain the actual altitude.

8. The attitude correction system of the airborne Rayleigh laser radar signal according to claim 7 is characterized in that: The processing module is also used to define the difference between the attitude angle at the next moment and the attitude angle at the previous moment of the attitude data as the jitter amount, calculate the sum of the average value of the pitch angle data and the jitter amount as the approximate value of the pitch angle, and calculate the sum of the average value of the roll angle data and the jitter amount as the approximate value of the roll angle.

9. The attitude correction system of the airborne Rayleigh laser radar signal according to claim 7, characterized in that: The calculation module is also used to construct a rotation matrix including pitch angle and roll angle for transforming from the carrier coordinate system to the geographic coordinate system, so as to establish the spatial position relationship of the carrier coordinate system relative to the geographic coordinate system; establish a polar coordinate system on the carrier coordinate system, use the zenith angle and azimuth angle in the polar coordinate system to describe the laser beam emission direction, and use the polar diameter of the polar coordinate system to describe the detection distance, so as to construct the spatial relative relationship between the laser beam emission direction and the carrier coordinate system.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for attitude correction of an airborne Rayleigh lidar signal as described in any one of claims 1 to 6 are implemented.

Images