Method and system for correcting installation angle of airborne laser wind finding radar

Abstract

The invention belongs to the technical field of laser wind-finding radars, and discloses a method and a system for correcting an installation angle of an airborne laser wind-finding radar, which utilize data measured by the radar in a flight process and reference data provided by an aircraft inertial navigation system to automatically and accurately calculate an installation angle deviation through a mathematical model and correct the installation angle deviation. The problem that a traditional installation angle calibration method is tedious in process and difficult to revise is solved, and the precision and reliability of wind field measurement are improved.

Description

Technical Field

[0001] This invention belongs to the field of laser wind measurement radar technology, specifically relating to a method and system for correcting measurement angle deviations caused by the installation angle of airborne laser wind measurement radar. Background Technology

[0002] Laser wind radar emits a laser beam into the atmosphere and receives the backscattered signals from aerosol particles, using the Doppler principle to invert the velocity vector of the wind field. When mounted on an aircraft platform, it can achieve rapid and accurate measurement of wind fields over a large area below flight paths, and has important applications in meteorological observation, aviation safety, and wind energy assessment.

[0003] The measurement accuracy of airborne laser wind-measuring radar is highly dependent on the accuracy of its installation angle relative to the aircraft's coordinate system. Ideally, the radar's measurement coordinate system should be transformed from the aircraft's navigation coordinate system through a fixed installation matrix. However, in actual installation, mechanical installation errors are unavoidable, causing deviations between the radar's actual installation angles (pitch, roll, and heading) and the theoretical design. These installation angle deviations directly affect wind vector inversion calculations, resulting in errors in wind speed and direction measurements. Traditional installation angle calibration methods typically rely on high-precision optical measurement equipment or ground calibration fields. The process is cumbersome, and during long-term use, the installation angle may undergo slight changes due to vibration, maintenance, etc., which traditional calibration methods struggle to detect and correct. Summary of the Invention

[0004] This invention addresses the problems of cumbersome and difficult-to-correct traditional installation angle calibration methods by providing an installation angle correction method and system for airborne laser wind measuring radar. It does not rely on external calibration equipment, but uses data measured by the radar itself during flight and reference data provided by the aircraft's inertial navigation system to automatically and accurately calculate the installation angle deviation through a mathematical model and correct it, thereby improving the accuracy and reliability of wind field measurement.

[0005] The technical solution of this invention is implemented as follows: In a first aspect, the present invention provides a method for correcting the installation angle of an airborne laser wind-measuring radar, which includes the following steps: Step S1: During the aircraft's level and constant-speed flight phase, and while the aircraft's altitude is within the range of the laser wind radar, simultaneously collect the following data: the raw radial velocity data sequence measured by the laser wind radar and the aircraft ground velocity vector provided by the airborne inertial navigation system. Pitch angle Roll angle and heading angle ; Step S2: Identify ground radial velocity from the laser wind radar radial velocity sequence ; Step S3: Measure the radial velocity of the ground. The ground speed data obtained from the laser wind-measuring radar is used as the basis for calculating the ground speed data measured by the laser radar in the ground coordinate system, based on the attitude angle data provided by the airborne inertial navigation system. ; Step S4: Calculate the ground velocity of the inertial navigation system in the radial direction in the ground coordinate system. ; Step S5: Establish the objective function: This includes setting the installation angle deviation. Define the objective function as the unknown to be solved. ; Step S6: Optimal Installation Angle Deviation Calculation: Find a set of installation angle deviation values ​​through an optimization algorithm. This makes the objective function defined in step S5... The value is the smallest; Step S7: Apply correction: Apply the obtained optimal installation angle deviation The corrected installation angle will be updated in the radar system installation parameters and used during subsequent wind field measurement data inversion. Perform coordinate transformation calculations.

[0006] As a further technical solution of the present invention: In step S2, the specific identification method is to identify a distance gate with the largest signal-to-noise ratio over a radial distance as the ground radial airspeed data.

[0007] As a further technical solution of the present invention: In step S5, the objective function is the ground speed data obtained by laser wind radar measurement. After installation angle deviation correction, the ground speed provided by the inertial navigation system is compared with that of the ground speed provided by the inertial navigation system. The sum of squares of the differences:

[0008] Where *f* is a function that projects the wind vector onto the biased beam direction.

[0009] As a further technical solution of the present invention: In step S1, the aircraft ground velocity vector Pitch angle Roll angle and heading angle It can be obtained through satellite navigation systems or Doppler radar systems.

[0010] As a further technical solution of the present invention: the installation angle deviation includes pitch angle deviation, roll angle deviation and heading angle deviation.

[0011] As a further technical solution of the present invention: if the pitch angle Roll angle and heading angle With any 1-2 installation angles already fixed, only calculation is needed. The remaining angular deviation.

[0012] As a further technical solution of the present invention: calculating the ground velocity of the inertial navigation system in the radial direction. Specifically: The ground velocity vector of the inertial navigation system By decomposing the beam direction of the airborne lidar, the ground velocity of the inertial navigation system in the radial direction can be obtained. .

[0013] As a further technical solution of the present invention: Calculate the ground velocity data obtained by lidar measurement in the ground coordinate system. Specifically: According to the pitch angle provided by the inertial navigation system Roll angle and heading angle Using the Euler transformation matrix, the ground velocity data obtained from lidar measurements is transformed... Transform to the geodetic coordinate system to obtain the ground velocity data measured by lidar in the ground coordinate system. .

[0014] As a further technical solution of the present invention: the optimization algorithm adopts the least squares method, gradient descent method or Levenberg-Marquardt algorithm for iterative solution.

[0015] Secondly, the present invention provides an installation angle correction system for an airborne laser wind measuring radar, comprising: Data Acquisition Module: During the aircraft's level, constant-speed flight phase, and when the aircraft's altitude is within the range of the laser wind radar, the following data are simultaneously acquired: the raw radial velocity data sequence measured by the laser wind radar and the aircraft ground velocity vector provided by the onboard inertial navigation system. Pitch angle Roll angle and heading angle ; The ground radial velocity identification module identifies ground radial velocity from the radial velocity sequence of a laser wind radar. Specifically, the method involves identifying a range gate with the highest signal-to-noise ratio over a radial distance, which is then used as the ground radial airspeed data. The radial ground velocity calculation module calculates the ground radial velocity. The ground speed data obtained from the laser wind-measuring radar is used as the basis for calculating the ground speed data measured by the laser radar in the ground coordinate system, based on the attitude angle data provided by the airborne inertial navigation system. Calculate the ground velocity of the inertial navigation system in the radial direction in the ground coordinate system. ; Install the angle deviation calculation and correction module to calculate the installation angle deviation. Define the objective function as the unknown to be solved. By optimizing the algorithm, a set of installation angle deviation values ​​is found. This makes the defined objective function Minimize the value of the optimal installation angle deviation obtained by the solution; The corrected installation angle will be updated in the radar system installation parameters and used during subsequent wind field measurement data inversion. Perform coordinate transformation calculations.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. High precision and self-containment: Direct analysis using flight data eliminates errors introduced by external calibration equipment, resulting in high correction accuracy. The system has self-calibration capabilities.

[0017] 2. Real-time and dynamic: This method can be executed in each flight mission or multiple flight phases, and can monitor and correct long-term drift of the installation angle caused by aircraft structural deformation or vibration, ensuring the long-term stability of the measurement.

[0018] 3. Low cost and high efficiency: No expensive calibration equipment or complex calibration process is required, saving time and economic costs and facilitating engineering applications.

[0019] 4. High reliability: This method is based on the physical principle of wind vector conservation. Under flat and uniform flight conditions, the data signal-to-noise ratio is high and the solution results are stable and reliable.

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 A flowchart illustrating the overall process of correcting the installation angle of an airborne laser wind-measuring radar according to the present invention; Figure 2 This is a schematic diagram of the installation angle deviation of the airborne laser wind measuring radar; Figure 3 This is a schematic diagram showing how the objective function changes with the installation angle deviation. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be described in more detail below with reference to the accompanying drawings.

[0023] In the accompanying drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of the present invention.

[0024] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0025] The following is in conjunction with the appendix Figure 1-3 The embodiments of the present invention will be described in detail below.

[0026] Example 1 This invention provides a method for correcting the installation angle of an airborne laser wind-measuring radar, which includes the following steps: Step S1: During the aircraft's level and constant-speed flight phase, and while the aircraft's altitude is within the range of the laser wind radar, simultaneously collect the following data: the raw radial velocity data sequence measured by the laser wind radar and the aircraft ground velocity vector provided by the airborne inertial navigation system. Pitch angle Roll angle and heading angle ; Step S2: Identify ground radial velocity from the laser wind radar radial velocity sequence ; Step S3: Measure the radial velocity of the ground. The ground speed data obtained from the laser wind-measuring radar is used as the basis for calculating the ground speed data measured by the laser radar in the ground coordinate system, based on the attitude angle data provided by the airborne inertial navigation system. ; Step S4: Calculate the ground velocity of the inertial navigation system in the radial direction in the ground coordinate system. ; Step S5: Establish the objective function: This includes setting the installation angle deviation. Define the objective function as the unknown to be solved. ; Step S6: Optimal Installation Angle Deviation Calculation: Find a set of installation angle deviation values ​​through an optimization algorithm. This makes the objective function defined in step S5... The value is the smallest; Step S7: Apply correction: Apply the obtained optimal installation angle deviation The corrected installation angle will be updated in the radar system installation parameters and used during subsequent wind field measurement data inversion. Perform coordinate transformation calculations.

[0027] Furthermore, in step S2, the specific identification method is to identify a distance gate with the highest signal-to-noise ratio over a radial distance, which is then used as the ground radial airspeed data.

[0028] Furthermore, in step S5, the objective function is the ground speed data obtained from the laser wind radar measurement. After installation angle deviation correction, the ground speed provided by the inertial navigation system is compared with that of the ground speed provided by the inertial navigation system. The sum of squares of the differences:

[0029] Where *f* is a function that projects the wind vector onto the biased beam direction.

[0030] Furthermore, in step S1, the aircraft ground velocity vector Pitch angle Roll angle and heading angle It can be obtained through satellite navigation systems or Doppler radar systems.

[0031] Furthermore, installation angle deviation includes pitch angle deviation, roll angle deviation, and yaw angle deviation.

[0032] Furthermore, if the pitch angle Roll angle and heading angle With any 1-2 installation angles already fixed, only calculation is needed. The remaining angular deviation.

[0033] Furthermore, the ground velocity of the inertial navigation system in the radial direction is calculated. Specifically: The ground velocity vector of the inertial navigation system By decomposing the beam direction of the airborne lidar, the ground velocity of the inertial navigation system in the radial direction can be obtained. .

[0034] Furthermore, the ground velocity data obtained from lidar measurements in the ground coordinate system is calculated. Specifically: According to the pitch angle provided by the inertial navigation system Roll angle and heading angle Using the Euler transformation matrix, the ground velocity data obtained from lidar measurements is transformed... Transform to the geodetic coordinate system to obtain the ground velocity data measured by lidar in the ground coordinate system. .

[0035] Furthermore, the optimization algorithm employs the least squares method, gradient descent method, or Levenburg-Marquardt algorithm for iterative solution.

[0036] Example 2 This invention provides a method for correcting the installation angle of an airborne laser wind measurement system, which includes the following steps: Step S1: Data Synchronization Acquisition. During the aircraft's level, constant-speed flight phase, the following data will be collected synchronously: The raw radial wind speed data sequence measured by laser wind radar; The airborne inertial navigation system provides the aircraft's ground velocity vector ( ), pitch angle ( ), roll angle ( ) and heading angle ( ); Step S2: Calculate the theoretical radial wind speed. Based on INS data and airspeed data, and combined with the principle of wind vector synthesis, calculate the theoretical radial wind speed in each beam direction of the lidar under ideal conditions with no installation deviation.

[0037] Specifically: a) Calculate the airspeed vector from airspeed and aircraft attitude.

[0038] b) Solve for the true wind vector based on the ground speed vector and air speed vector. (Needs to be converted to the same coordinate system).

[0039] c) The actual wind vector Projecting the beams onto the laser array at its nominal installation angle yields a series of theoretical radial wind speed values. .

[0040] Step S3: Establish the error model and objective function. The installation angle deviation will be considered. As the unknown to be determined, an error model is established between the actual measurement and the theoretical value.

[0041] Define the objective function This function represents the radar-measured radial wind speed at the effective sampling points of the beam. The sum of squares of the difference between the theoretical radial wind speed and the speed after correction for installation angle deviation.

[0042]

[0043] in This is a function that projects the wind vector onto the direction of the biased beam.

[0044] Step S4: Calculation of Optimal Installation Angle Deviation. A set of installation angle deviation values ​​is found through an optimization algorithm. This makes the objective function defined in step S3... The value of is minimized. Optimization algorithms can be used to iteratively solve the problem using the least squares method, gradient descent method, or Levenburg-Marquardt algorithm.

[0045] Step S5: Apply corrections. Apply the obtained optimal installation angle deviation... The corrected installation angle will be updated in the radar system installation parameters and used during subsequent wind field measurement data inversion. Perform coordinate transformation calculations.

[0046] Example 3 This invention provides a method for correcting the installation angle of a laser wind-measuring radar, which includes the following steps: S1: Synchronous Data Acquisition. During the aircraft's level and constant-speed flight phase, radial wind speed measurement data from the laser wind radar, attitude data from the inertial navigation system, and ground speed data are acquired simultaneously.

[0047] S2: Based on the collected inertial navigation data and airspeed data, and combined with the principle of wind vector synthesis, calculate the theoretical radial wind speed in each beam direction of the lidar under ideal conditions without installation deviation.

[0048] S3: Using the installation angle deviation as the unknown to be determined, establish an error model between the actual measurement and the theoretical value.

[0049] S4: The optimal installation angle deviation is obtained by optimizing the minimum value of the objective function.

[0050] S5: The subsequent measurements of the laser wind measuring radar are corrected using the optimal installation angle deviation.

[0051] Even if the aircraft's attitude and ground speed data are not collected using an inertial navigation system.

[0052] Installation angle deviations include pitch angle deviation, roll angle deviation, and yaw angle deviation.

[0053] This invention provides an installation angle correction system for an airborne laser wind-measuring radar, comprising: Data Acquisition Module: During the aircraft's level, constant-speed flight phase, and when the aircraft's altitude is within the range of the laser wind radar, the following data are simultaneously acquired: the raw radial velocity data sequence measured by the laser wind radar and the aircraft ground velocity vector provided by the onboard inertial navigation system. Pitch angle Roll angle and heading angle ; The ground radial velocity identification module identifies ground radial velocity from the radial velocity sequence of a laser wind radar. Specifically, the method involves identifying a range gate with the highest signal-to-noise ratio over a radial distance, which is then used as the ground radial airspeed data. The radial ground velocity calculation module calculates the ground radial velocity. The ground speed data obtained from the laser wind-measuring radar is used as the basis for calculating the ground speed data measured by the laser radar in the ground coordinate system, based on the attitude angle data provided by the airborne inertial navigation system. Calculate the ground velocity of the inertial navigation system in the radial direction in the ground coordinate system. ; Install the angle deviation calculation and correction module to calculate the installation angle deviation. Define the objective function as the unknown to be solved. By optimizing the algorithm, a set of installation angle deviation values ​​is found. This makes the defined objective function Minimize the value of the optimal installation angle deviation obtained by the solution; The corrected installation angle will be updated in the radar system installation parameters and used during subsequent wind field measurement data inversion. Perform coordinate transformation calculations.

[0054] Thus, the objective of this invention has been achieved.

[0055] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for correcting the installation angle of an airborne laser wind-measuring radar, characterized in that, Includes the following steps: Step S1: During the aircraft's level and constant-speed flight phase, and while the aircraft's altitude is within the range of the laser wind radar, simultaneously collect the following data: the raw radial velocity data sequence measured by the laser wind radar and the aircraft ground velocity vector provided by the airborne inertial navigation system. Pitch angle Roll angle and heading angle ; Step S2: Identify ground radial velocity from the laser wind radar radial velocity sequence ; Step S3: Measure the radial velocity of the ground. The ground speed data obtained from the laser wind-measuring radar is used as the basis for calculating the ground speed data measured by the laser radar in the ground coordinate system, based on the attitude angle data provided by the airborne inertial navigation system. ; Step S4: Calculate the ground velocity of the inertial navigation system in the radial direction in the ground coordinate system. ; Step S5: Establish the objective function: This includes setting the installation angle deviation. Define the objective function as the unknown to be solved. ; Step S6: Optimal Installation Angle Deviation Calculation: Find a set of installation angle deviation values ​​through an optimization algorithm. This makes the objective function defined in step S5... The value is the smallest; Step S7: Apply correction: Apply the obtained optimal installation angle deviation The corrected installation angle will be updated in the radar system installation parameters and used during subsequent wind field measurement data inversion. Perform coordinate transformation calculations.

2. The method for correcting the installation angle of an airborne laser wind-measuring radar according to claim 1, characterized in that, In step S2, the specific identification method is to identify a distance gate with the highest signal-to-noise ratio over a radial distance, which is then used as the ground radial airspeed data.

3. The method for correcting the installation angle of an airborne laser wind-measuring radar according to claim 1, characterized in that, In step S5, the objective function is the ground speed data obtained from the laser wind radar measurement. After installation angle deviation correction, the ground speed provided by the inertial navigation system is compared with that of the ground speed provided by the inertial navigation system. The sum of squares of the differences: Where *f* is a function that projects the wind vector onto the biased beam direction.

4. The method for correcting the installation angle of an airborne laser wind-measuring radar according to claim 1, characterized in that, In step S1, the aircraft ground velocity vector Pitch angle Roll angle and heading angle It can be obtained through satellite navigation systems or Doppler radar systems.

5. The method for correcting the installation angle of an airborne laser wind-measuring radar according to claim 1, characterized in that, Installation angle deviations include pitch angle deviation, roll angle deviation, and yaw angle deviation.

6. The method for correcting the installation angle of an airborne laser wind-measuring radar according to claim 5, characterized in that, If pitch angle Roll angle and heading angle With any 1-2 installation angles already fixed, only calculation is needed. The remaining angular deviation.

7. The method for correcting the installation angle of an airborne laser wind-measuring radar according to claim 1, characterized in that, Calculate the ground velocity of the inertial navigation system in the radial direction. Specifically: The ground velocity vector of the inertial navigation system By decomposing the beam direction of the airborne lidar, the ground velocity of the inertial navigation system in the radial direction can be obtained. .

8. The method for correcting the installation angle of an airborne laser wind-measuring radar according to claim 1, characterized in that, Calculate the ground velocity data obtained from lidar measurements in the ground coordinate system. Specifically: According to the pitch angle provided by the inertial navigation system Roll angle and heading angle Using the Euler transformation matrix, the ground velocity data obtained from lidar measurements is transformed... Transform to the geodetic coordinate system to obtain the ground velocity data measured by lidar in the ground coordinate system. .

9. The method for correcting the installation angle of an airborne laser wind-measuring radar according to claim 1, characterized in that, The optimization algorithm uses the least squares method, gradient descent method, or Levenburg-Marquardt algorithm for iterative solution.

10. A system for correcting the installation angle of an airborne laser wind-measuring radar, characterized in that, include: Data Acquisition Module: During the aircraft's level, constant-speed flight phase, and when the aircraft's altitude is within the range of the laser wind radar, the following data are simultaneously acquired: the raw radial velocity data sequence measured by the laser wind radar and the aircraft ground velocity vector provided by the onboard inertial navigation system. Pitch angle Roll angle and heading angle ; The ground radial velocity identification module identifies ground radial velocity from the radial velocity sequence of a laser wind radar. Specifically, the method involves identifying a range gate with the highest signal-to-noise ratio over a radial distance, which is then used as the ground radial airspeed data. The radial ground velocity calculation module calculates the ground radial velocity. The ground speed data obtained from the laser wind-measuring radar is used as the basis for calculating the ground speed data measured by the laser radar in the ground coordinate system, based on the attitude angle data provided by the airborne inertial navigation system. Calculate the ground velocity of the inertial navigation system in the radial direction in the ground coordinate system. ; Install the angle deviation calculation and correction module to calculate the installation angle deviation. Define the objective function as the unknown to be solved. By optimizing the algorithm, a set of installation angle deviation values ​​is found. This makes the defined objective function Minimize the value of the optimal installation angle deviation obtained by the solution; The corrected installation angle will be updated in the radar system installation parameters and used during subsequent wind field measurement data inversion. Perform coordinate transformation calculations.

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