Wind speed and wind direction determination method for complex scene of helicopter

Abstract

The invention provides a wind speed and wind direction determination method for a complex scene of a helicopter, the helicopter is equipped with a single-shaft atmospheric engine, and the wind speed and wind direction determination method comprises the following steps: step 1, extracting a course angle psi, an east direction speed VE and a north direction speed VN of the helicopter based on an inertial navigation system; 2, extracting the comprehensive vacuum speed Vt of the single-axis atmospheric engine based on an inertial navigation system; 3, determining the wind speed and the wind direction according to the course angle psi, the east speed VE, the north speed VN and the comprehensive vacuum speed Vt; and 4, dynamically adjusting the course angle psi, the east wind speed VWE and the north wind speed VWN according to the errors of the wind speed and the wind direction determined in the step 3, and re-determining the wind speed and the wind direction until the wind speed and the wind direction are determined accurately. The east speed, north speed and course angle of the integrated navigation system and the vacuum speed of the single-axis atmospheric engine are comprehensively utilized, the wind speed and direction are determined through calculation, the problem of inaccurate wind speed and direction calculation in the prior art is solved, and the wind speed and direction output accuracy is effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of helicopters, and in particular relates to a method for determining wind speed and direction for complex helicopter scenes. Background Art

[0002] Helicopters fly by relying on rotors. When the rotor blades rotate in the air, the rotors generate downward airflow. Since the airflow speed on the upper surface of the rotor is faster than that on the lower surface, an upward lift is formed, allowing the helicopter to hover in the air or take off and land vertically. At the same time, the rotation of the rotor generates propulsion, allowing the helicopter to fly horizontally. The rotor controls the attitude and direction of the helicopter by changing the blade angle and rotation speed. The rotor adjusts the size and direction of the lift and propulsion by changing the angle and rotation speed, allowing the helicopter to fly forward, backward, left or right, or climb or descend.

[0003] In addition to the rotor, the helicopter is equipped with a tail wing to offset the torque generated by the rotor. The tail wing balances the torque of the rotor by generating an opposite torque force, thereby maintaining the stability and balance of the helicopter. The tail wing can also control the direction of the helicopter. When the helicopter needs to turn left or right, the angle and position of the tail rotor are adjusted to generate thrust to the left or right, causing the helicopter to change direction.

[0004] The helicopter generates aerodynamic force due to the relative motion between its own rotor and the surrounding air, which is decomposed into lift, torque and horizontal force. The slipstream theory, blade element theory and vortex theory are usually used to analyze and calculate the interaction between the rotor and the surrounding air. Among them: the slipstream theory regards the rotor as a disk that generates pulling force, and the flow field affected by the rotor as a one-dimensional flow in the slipstream with the circumference of the disk as the boundary. According to the momentum theorem and the kinetic energy theorem, the relationship between the pulling force and the required power and the speed change in the slipstream is obtained; the blade element theory divides the rotor blades into many micro-segments (blade elements), and regards the relative flow around each blade element as a two-dimensional flow that is independent of each other, and the aerodynamic force and torque of the blade section are obtained, and then the aerodynamic force and torque of the entire rotor are obtained by integrating along the blade radius and averaging along the azimuth; the vortex theory uses a certain vortex system to replace the effect of the rotor blade on the surrounding air, so as to determine the induced velocity at any point in space.

[0005] The air movement caused by the rotation of a helicopter's own rotor is a complex process. In addition, single-axis atmospheric engines have poor accuracy at low speeds and cannot output airspeed in three directions, resulting in inaccurate calculations of wind speed and direction. Summary of the invention

[0006] The purpose of the present invention is to solve the shortcomings of the prior art that the wind direction and wind speed cannot be accurately determined, and to provide a method for determining the wind speed and wind direction for complex helicopter scenes. The method comprehensively utilizes the east speed, north speed, heading angle of the combined navigation system, and the true airspeed of the single-axis atmospheric engine, and determines the wind speed and wind direction through calculation, thereby solving the problem of inaccurate calculation of wind speed and wind direction and effectively improving the accuracy of wind speed and wind direction output.

[0007] To achieve the above purpose, the technical solution provided by the present invention is:

[0008] A method for determining wind speed and direction for a complex helicopter scene, wherein the helicopter is equipped with a single-axis atmospheric engine, and the method for determining wind speed and direction comprises:

[0009] Step 1: Extract the heading angle Ψ and eastward speed V of the helicopter based on the inertial navigation system E and northward velocity V N ;

[0010] Step 2: Extract the comprehensive true air speed V of the single-axis atmospheric machine based on the inertial navigation system t ;

[0011] Step 3: According to the heading angle Ψ and the eastward speed V E , northward speed V N and the integrated true airspeed V t , determine wind speed and direction, specifically:

[0012] The wind speed is calculated using formula (1):

[0013]

[0014] In formula (1), V W Indicates wind speed, V WE Indicates the east wind speed, V WN Indicates the north wind speed;

[0015] The wind direction is calculated using formula (2):

[0016]

[0017] In formula (2), Ψ W Indicates wind direction, V WE Indicates the east wind speed, V WN Indicates the north wind speed; if the future wind direction is defined as the wind direction, the wind direction Ψ is determined accordingly W as follows:

[0018] When the east wind speed V WE <0, North wind speed V WN When <0, the wind direction is determined as ΨW ; When the east wind speed V WE =0, north wind speed V WN When the east wind speed V WE >0, North wind speed V WN When <0, the wind direction is determined to be 360°+Ψ W ;

[0019] When the east wind speed V WE <0, North wind speed V WN = 0, the wind direction is determined to be 90°; when the east wind speed V WE =0, north wind speed V WN = 0, the wind direction is determined to be calm; when the east wind speed V WE >0, North wind speed V WN =0, the wind direction is determined to be 270°;

[0020] When the east wind speed V WE <0, North wind speed V WN When >0, the wind direction is determined to be 180°+Ψ W ; When the east wind speed V WE =0, north wind speed V WN >0, the wind direction is determined to be 180°; when the east wind speed V WE >0, North wind speed V WN When >0, the wind direction is determined to be 180°+Ψ W .

[0021] As a further limitation of the present invention, the step 1 comprises:

[0022] Step (11) obtaining the heading angle Ψ of the helicopter through a strapdown inertial navigation system;

[0023] Step (12) obtains the ground speed of the helicopter relative to the earth through the strapdown inertial navigation system, and obtains the eastward speed V of the helicopter according to the ground speed E and northward velocity V N .

[0024] As a further limitation of the present invention, the step 2 comprises:

[0025] Step (21) obtaining the angle of attack α and the sideslip angle β of the helicopter through a strapdown inertial navigation system;

[0026] Step (22) obtains the comprehensive true air speed V of the single-axis atmospheric machine through a strapdown inertial navigation system t , where the comprehensive true air speed V t Including longitudinal velocity component, transverse velocity component and normal velocity component;

[0027] Step (23) calculates the comprehensive true air speed V obtained by the single-axis atmospheric engine according to the angle of attack α and the sideslip angle β. t The conversion expression is:

[0028]

[0029] In formula (3), represents the wind speed matrix, V t ×sin(β) represents the vertical axis velocity component, V t ×cos(α)×cos(β) represents the horizontal axis velocity component, -V t ×sin(α)×cos(β) represents the normal velocity component.

[0030] As a further limitation of the present invention, in the formula (1) of step 3, Indicates the square of wind speed, wind speed V W The larger the wind direction W The smaller the calculation error.

[0031] As a further limitation of the present invention, it also includes:

[0032] Step 4: According to the error of wind speed and wind direction determined in step 3, the heading angle Ψ and the east wind speed V are dynamically adjusted. WE , North wind speed V WN , re-determine the wind speed and wind direction until the wind speed and wind direction are accurately determined.

[0033] As a further limitation of the present invention, in the step 4, the step 3 of determining the error of wind speed and wind direction includes:

[0034] (1) The wind speed V determined in step 3 W When the wind direction is small, W The calculation error increases dramatically;

[0035] (2) When the helicopter is flying backward, flying sideways, turning, climbing or descending, the wind speed V determined in step 3 is W and wind direction W Calculation errors occur during synchronization;

[0036] (3) When the helicopter is flying at a low speed, the duration of the maneuvering flight is short, or before the maneuvering flight resumes high-speed forward flight, the wind direction Ψ determined in step 3 W An error occurred.

[0037] As a further limitation of the present invention, in step 4, the heading angle Ψ and the east wind speed V are dynamically adjusted. WE , North wind speed V WN , re-determine the wind speed and direction until the wind speed and direction are accurate, including:

[0038] (1) Determine whether condition 1 is met. If condition 1 is met, cache the current heading angle Ψ and eastward speed V of the helicopter every 1 second. E , northward speed V N , 1s average east wind speed V WE and north wind speed V WN , the maximum cache data is 30s; Substitute into formula (1) and formula (2) to determine the wind speed and direction;

[0039] Among them, the condition 1 is: the helicopter meets the current ground speed> 36km / h and the comprehensive true air speed V in complex scenes at the same time. t >40km / h, the absolute value of (track angle - heading angle Ψ) <45°;

[0040] (2) Starting from the time when the cached data is full for 30 seconds, determine whether condition 2 is met every 1 second. If condition 2 is met, cache the 30 seconds of east wind speed V WE and north wind speed V WN After taking the average value, record it as and If condition 2 is not met or the cached data is less than 30 seconds, the 1-second average east wind speed V WE and north wind speed V WN Assign to and Will and Substitute into formula (1) and formula (2) to determine the wind speed and direction;

[0041] Among them, the condition 2 is: (a) the maximum cruising speed V of the helicopter within the current 30 seconds xmax and the minimum cruising speed V xmin The absolute value of the difference |ΔV x |≤20km / h; (b) The maximum heading value of the helicopter within the current 30s H max , minimum heading value H min The absolute value of the difference |ΔH|≤10°;

[0042] (3) Starting from the time when the cached data is full for 30 seconds, determine whether condition 3 is met every 1 second. If condition 3 is met, cache the east wind speed V for 30 seconds. WE and north wind speed V WN After taking the average value, record the calculation time and the 30s average. 30s average Current heading angle Ψ, current integrated true airspeed V t ;like and If neither is substituted into formula (1) or formula (2) for calculation, then like and Substituting into formula (1) and formula (2) for calculation, we get Will and Substitute into formula (1) and formula (2) to determine the wind speed and direction;

[0043] Among them, the condition 3 is: (a) the maximum cruising speed V of the helicopter within the current 30 seconds xmax and the minimum cruising speed V xmin The absolute value of the difference |ΔV x |≤5km / h; (b) The maximum heading value of the helicopter within the current 30s H max , minimum heading value H min The absolute value of the difference |ΔH|≤3°.

[0044] As a further limitation of the present invention, in step 4, the heading angle Ψ and the east wind speed V are dynamically adjusted. WE , North wind speed V WN , re-determine the wind speed and direction until the wind speed and direction are accurately determined, and also include:

[0045] (4) Select the current average of the helicopter and Substitute into formula (1) and formula (2) to determine the wind speed and direction; where, and The expression is:

[0046]

[0047] In formula (4), and Obtained through step 4 (3), and Obtained by step 4 (2);

[0048] (5) Select the helicopter's current 30-second average easterly wind speed and northerly wind speed after calibration compensation and Substitute into formula (1) and formula (2) to determine the wind speed and direction;

[0049] (6) When condition 4 is met, the wind speed and direction determined by formula (1) and formula (2) remain unchanged; wherein condition 4 is: comprehensive true air speed Vt ≤40km / h, or ground speed ≤36km / h, or the absolute value of the drift angle is >90°.

[0050] The advantages of the present invention are:

[0051] The present invention comprehensively utilizes the easting speed, northing speed, heading angle of the combined navigation system and the true airspeed of the single-axis atmospheric engine to determine the wind speed and direction through calculation, thereby solving the problem of inaccurate calculation of wind speed and direction and effectively improving the accuracy of wind speed and direction output.

[0052] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0054] Figure 1 :The present invention provides a method for determining wind speed and direction for complex helicopter scenes Figure 1 ;

[0055] Figure 2 :The present invention provides a method for determining wind speed and direction for complex helicopter scenes Figure 2 ;

[0056] Figure 3 : The wind direction truth table outputted externally in step 3 provided by the present invention;

[0057] Figure 4 : The velocity vector triangle diagram of the complex helicopter scene provided by the present invention;

[0058] Figure 5 : Illustration of wind speed and direction simulation data provided by the present invention;

[0059] Figure 6 : Illustration of the simulation data of the bias angle provided by the present invention;

[0060] Figure 7 : The present invention provides a parameter diagram of the speed and angle of a helicopter in a complex scene. DETAILED DESCRIPTION

[0061] Embodiments of the present invention are described in detail below. The embodiments are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0062] See also Figure 1 and Figure 2The embodiment of the present invention provides a method for determining wind speed and direction for a complex helicopter scene. The helicopter is equipped with a single-axis atmospheric engine. The method for determining wind speed and direction in the embodiment of the present invention includes:

[0063] Step 1: Extract the heading angle Ψ and eastward speed V of the helicopter based on the inertial navigation system E and northward velocity V N .

[0064] Specifically, step 1 of the embodiment of the present invention specifically includes:

[0065] Step (11) obtaining the heading angle Ψ of the helicopter through a strapdown inertial navigation system;

[0066] Step (12) obtains the ground speed of the helicopter relative to the earth through the strapdown inertial navigation system, and obtains the eastward speed V of the helicopter based on the ground speed E and northward velocity V N .

[0067] In step 1, the embodiment of the present invention reasonably sets the inertial navigation data of the strapdown inertial navigation system, optimizes the sliding filter parameters of the strapdown inertial navigation system, and dynamically self-calibrates during reciprocating flight, and adaptively adjusts the weighted time scale of real-time calculation and historical data to obtain the heading angle Ψ and eastward speed V of the helicopter in complex scenes. E and northward velocity V N .

[0068] Step 2: Extract the comprehensive true air speed V of the single-axis atmospheric machine based on the inertial navigation system t .

[0069] Specifically, the above step 2 of the embodiment of the present invention includes:

[0070] Step (21) obtains the attack angle α and sideslip angle β of the helicopter through a strapdown inertial navigation system;

[0071] Step (22) obtains the integrated true air speed V of the single-axis atmospheric machine through the strapdown inertial navigation system t ; Among them, the comprehensive true air speed V t Including longitudinal velocity component, transverse velocity component and normal velocity component;

[0072] Step (23) calculates the comprehensive true air speed V obtained by the single-axis atmospheric engine according to the angle of attack α and the sideslip angle β. t The conversion expression is:

[0073]

[0074] In formula (3), represents the wind speed matrix, V t×sin(β) represents the vertical axis velocity component, V t ×cos(α)×cos(β) represents the horizontal axis velocity component, -V t ×sin(α)×cos(β) represents the normal velocity component.

[0075] In the above step 2 of the embodiment of the present invention, the attack angle α, the sideslip angle β, and the comprehensive true air speed V of the helicopter are obtained by reasonably setting the atmospheric data. t .

[0076] Step 3: According to the heading angle Ψ and the eastward speed V E , northward speed V N and the integrated true airspeed V t , determine wind speed and direction. See Figure 4 , specifically:

[0077] The embodiment of the present invention uses formula (1) to calculate the wind speed, which is expressed as:

[0078]

[0079] In formula (1), V W Indicates wind speed, V WE Indicates the east wind speed, V WN Indicates the north wind speed;

[0080] The embodiment of the present invention uses formula (2) to calculate the wind direction, which is expressed as:

[0081]

[0082] In formula (2), Ψ W Indicates wind direction, V WE Indicates the east wind speed, V WN Indicates the north wind speed. If the incoming wind direction is defined as wind direction, please refer to Figure 3 , thus determining the wind direction Ψ W as follows:

[0083] When the east wind speed V WE <0, North wind speed V WN When <0, the wind direction is determined as Ψ W ; When the east wind speed V WE =0, north wind speed V WN When the east wind speed V WE >0, North wind speed V WN When <0, the wind direction is determined to be 360°+Ψ W ;

[0084] When the east wind speed V WE <0, North wind speed VWN = 0, the wind direction is determined to be 90°; when the east wind speed V WE =0, north wind speed V WN = 0, the wind direction is determined to be calm; when the east wind speed V WE >0, North wind speed V WN =0, the wind direction is determined to be 270°;

[0085] When the east wind speed V WE <0, North wind speed V WN When >0, the wind direction is determined to be 180°+Ψ W ; When the east wind speed V WE =0, north wind speed V WN >0, the wind direction is determined to be 180°; when the east wind speed V WE >0, North wind speed V WN When >0, the wind direction is determined to be 180°+Ψ W .

[0086] In the formula (1) of the above step 3 of the embodiment of the present invention, Indicates the square of wind speed, wind speed V W The larger the wind direction W The smaller the calculation error.

[0087] The embodiment of the present invention optimizes the wind direction calculation output conditions, optimizes the drift angle calculation, the steady-state and real-time solution weighting and other technical measures, optimizes the wind speed and wind direction calculation output logic, and uses formula (1) and formula (2) to obtain the wind direction and wind speed.

[0088] Preferably, the physical quantities involved in determining the wind speed and direction in the embodiment of the present invention include: the eastward speed, northward speed, pitch angle, roll angle, heading angle of the strapdown inertial navigation system, and the true air speed of the vacuum air machine. Figure 7 , Figure 7 (a) Figure 7 (b) Figure 7 (d) Figure 7 (e) shows the direction of the load factor, velocity vector and air flow when the helicopter moves along the flight path. The climb angle, pitch angle and angle of attack of the helicopter during the movement are shown in Figure 7 As shown in (a), the sideslip angle, track angle and heading change angle during the helicopter movement are as follows: Figure 7 As shown in (b), the roll angle of the helicopter during motion is Figure 7 As shown in (c), the angle of attack, pitch angle and climb angle during the helicopter movement are as follows: Figure 7 As shown in (d), the sideslip angle, track angle and heading change angle during the helicopter movement are as follows: Figure 7 (e) as shown.

[0089] Among the physical quantities used in the process of determining wind speed and wind direction in the embodiment of the present invention, the ground speed, heading angle, and attitude angle of the strapdown inertial navigation system have high accuracy, while the true air speed accuracy of the vacuum atmospheric machine is low, and the smaller the true air speed, the greater the error in the measurement of the true air speed. When 0<atmospheric true air speed≤20km / h, the true air speed accuracy output by the vacuum atmospheric machine is too low to be assessed. In the embodiment of the present invention, due to the error in the calculation of the northeast component parameters of the wind speed, the east wind speed V WE , North wind speed V WN Differentiate to get wind speed V W The calculation error equation is expressed as:

[0090]

[0091] In formula (5), δψ W Indicates wind speed V W The calculation error, V WN Indicates the north wind speed, δV WE Indicates the north wind speed error, V WE Indicates the east wind speed, δV WN Indicates the east wind speed error. In the denominator of formula (5), It represents the square of wind speed. Under the condition of the same wind speed component measurement error, the greater the wind speed, the smaller the calculation error of wind direction. When the wind speed is small, the calculation error of wind direction will increase sharply.

[0092] In the embodiment of the present invention, the north wind speed error δV WE , East wind speed error δV WN , is due to the wind speed error caused by the helicopter in backward flight, side flight, turning, climbing, and descending scenarios, including: (1) There is an error in the calculation of the northeast component parameters of the wind speed; (2) The actual longitudinal airspeed of the helicopter in the carrier environment is a valid value, but because the single-axis atmospheric machine cannot measure the backward airspeed, the comprehensive true airspeed V obtained in step 2 is t The longitudinal airspeed is 0; (3) The forward flight heading of the carrier aircraft and the integrated true airspeed V t The actual direction does not coincide with the wind direction Ψ W Real-time calculation; (4) Changes in the aircraft's forward flight heading, comprehensive true airspeed V t The change of projection component causes the wind direction value to jump.

[0093] Furthermore, the above (4) of the embodiment of the present invention specifically subtracts the projections of the helicopter's ground speed and the comprehensive true air speed of the single-axis vacuum machine on the longitudinal axis, the transverse axis, and the normal axis to obtain the three-axis components of the wind speed, and then calculates the three-axis composite wind speed based on the three-axis components, and calculates the wind direction through the three-axis components of the wind speed. When the heading of the helicopter does not coincide with the actual direction of the comprehensive true air speed, the wind direction is calculated in real time; however, when the heading of the carrier aircraft changes, the projection component of the comprehensive true air speed changes, thereby causing the value of the wind direction to jump. In order to overcome the error and improve the accuracy of the wind speed and wind direction, the embodiment of the present invention adjusts the errors of the wind speed and wind direction through the following step four until the wind speed and wind direction are accurately determined.

[0094] Step 4: According to the wind speed and wind direction errors determined in step 3, dynamically adjust the heading angle Ψ and the east wind speed V WE , North wind speed V WN , re-determine the wind speed and wind direction until the wind speed and wind direction are accurately determined.

[0095] Specifically, in the above step 4 of the embodiment of the present invention, determining the errors of wind speed and wind direction according to step 3 includes:

[0096] (1) Wind speed V determined in step 3 W When the wind direction is small, W The calculation error increases dramatically;

[0097] (2) When the helicopter is flying backward, flying sideways, turning, climbing, or descending, the wind speed V determined in step 3 is W and wind direction W Calculation errors occur during synchronization;

[0098] (3) When the helicopter is flying at a low speed, the duration of the maneuvering flight is short, or before the maneuvering flight resumes high-speed forward flight, the wind direction determined in step 3 is W An error occurred.

[0099] Furthermore, in the above step 4 of the embodiment of the present invention, the heading angle Ψ and the east wind speed V are dynamically adjusted. WE , North wind speed V WN , re-determine the wind speed and direction until the wind speed and direction are accurate, including:

[0100] (1) Determine whether condition 1 is met. If condition 1 is met, cache the current heading angle Ψ and eastward speed V of the helicopter every 1 second. E , northward speed V N , 1s average east wind speed V WE and north wind speed V WN , the maximum cache data is 30s; substitute into formula (1) and formula (2) to determine the wind speed and direction.

[0101] Among them, condition 1 is: the helicopter meets the current ground speed > 36km / h and the comprehensive true air speed V in complex scenes at the same time. t >40km / h, the absolute value of (track angle - heading angle Ψ) is <45°.

[0102] (2) Starting from the time when the cached data is full for 30 seconds, determine whether condition 2 is met every 1 second. If condition 2 is met, cache the 30 seconds of east wind speed V WE and north wind speed V WN After taking the average value, record it as and If condition 2 is not met or the cached data in (1) is less than 30 seconds, the 1-second average east wind speed V WE and north wind speed V WN Assign to and Will and Substitute into formula (1) and formula (2) to determine the wind speed and direction.

[0103] Among them, condition 2 is: (a) the maximum cruising speed V of the helicopter within the current 30 seconds xmax and the minimum cruising speed V xmin The absolute value of the difference |ΔV x |≤20km / h; (b) The maximum heading value of the helicopter within the current 30s H max , minimum heading value H min The absolute value of the difference |ΔH|≤10°.

[0104] (3) Starting from the time when the cached data is full for 30 seconds, determine whether condition 3 is met every 1 second. If condition 3 is met, cache the east wind speed V for 30 seconds. WE and north wind speed V WN After taking the average value, record the calculation time and the 30s average. 30s average Current heading angle Ψ, current integrated true airspeed V t ;like and If neither is substituted into formula (1) or formula (2) for calculation, then like and Substituting into formula (1) and formula (2) for calculation, we get Will and Substitute into formula (1) and formula (2) to determine the wind speed and direction.

[0105] Among them, condition 3 is: (a) the maximum cruising speed V of the helicopter within the current 30 seconds xmax and the minimum cruising speed V xmin The absolute value of the difference |ΔV x |≤5km / h; (b) The maximum heading value of the helicopter within the current 30s H max , minimum heading value H min The absolute value of the difference |ΔH|≤3°;

[0106] (4) Select the current average of the helicopter and Substitute into formula (1) and formula (2) to determine the wind speed and direction; where, and The expression is:

[0107]

[0108] In formula (4), and Obtained through step 4 (3), and Obtained through step 4 (2).

[0109] (5) Select the helicopter's current 30-second average easterly wind speed and northerly wind speed after calibration compensation and Substitute into formula (1) and formula (2) to determine the wind speed and direction;

[0110] (6) When condition 4 is met, the wind speed and direction determined by formula (1) and formula (2) remain unchanged; where condition 4 is: comprehensive true air speed V t ≤40km / h, or ground speed ≤36km / h, or the absolute value of the drift angle is >90°.

[0111] It should be noted that in (3) of the embodiment of the present invention, if (a) and (b) of condition 3 are met, the east wind speed and north wind speed buffered for 30 seconds are averaged, and the time of this calculation, the 30-second average, and the average value are recorded. 30s average Current heading angle, attitude matrix, integrated true airspeed, and damping height. If two records are met, the heading angle, time, integrated true airspeed, and damping height recorded after the conditions are met this time are compared with the heading angle, time, integrated true airspeed, and damping height recorded after the conditions are met last time. If the following conditions (1)-(4) are met, calibration calculation is performed. Otherwise, only the record is updated without updating the calibration matrix:

[0112] (1) The absolute value of the heading difference between two consecutive records (normalized to -180° to 180°) is greater than 160 degrees;

[0113] (2) The true airspeed recorded twice is greater than 100 km / h;

[0114] (3) The time interval between two records is less than 540 seconds;

[0115] (4) The difference in damping height between the two records is less than 200m.

[0116] Specifically, the calibration matrix calculation formula is:

[0117]

[0118] In formula (6), is the wind speed component of two consecutive records, the matrix and matrix is the posture matrix of two adjacent records.

[0119] More specifically, the expression for determining whether the calibration matrix is ​​updated is:

[0120]

[0121] In formula (7), c p represents the update matrix, true air speed V t1 and true airspeed V t2 It represents the atmospheric true air speed of the single-axis atmospheric machine recorded twice consecutively. True airspeed V t1 、True air speed V t2 If the unit dimension of the matrix is ​​consistent, update the matrix c p If |c p (1)|>5° / 57.3 or c p (2)|>30km / h, then c is not updated p . Matrix c p The initial value of is 0, and it is updated if the above judgment conditions are met.

[0122] See also Figure 5 and Figure 6 , the embodiment of the present invention compares the flight test data with the calculation simulation data, Figure 5 The wind direction is shown at the top and the wind speed is shown at the bottom. The blue line is the test flight data and the yellow line is the simulation data. Figure 5 It can be seen that the wind speed and direction calculated by the embodiment of the present invention are basically stable and basically consistent with the actual situation. Figure 6The figure shows the comparison between the test flight data and the calculation simulation data of the drift angle, where the orange line is the test flight data and the blue line is the simulation data. Figure 6 By comparison, it can be seen that the deviation angle fluctuation phenomenon obtained in the embodiment of the present invention is basically consistent with the actual situation.

[0123] The embodiment of the present invention comprehensively utilizes the easting speed, northing speed, heading angle of the combined navigation system, and the true airspeed of the single-axis atmospheric engine, and determines the wind speed and direction through calculation, thereby solving the problem of inaccurate calculation of wind speed and direction and effectively improving the accuracy of wind speed and direction output.

[0124] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be included in the protection scope of the present invention.

Claims

1. A method for determining wind speed and direction in complex helicopter scenes, characterized in that: The helicopter is equipped with a single-axis atmospheric engine, and the method for determining wind speed and direction includes: Step 1: Extract the heading angle Ψ and eastward speed V of the helicopter based on the inertial navigation system E and northward velocity V N ; Step 2: Extract the comprehensive true air speed V of the single-axis atmospheric machine based on the inertial navigation system t ; Step 3: According to the heading angle Ψ and the eastward speed V E , northward speed V N and the integrated true airspeed V t , determine wind speed and direction, specifically: The wind speed is calculated using formula (1): In formula (1), V W Indicates wind speed, V WE Indicates the east wind speed, V WN Indicates the north wind speed; The wind direction is calculated using formula (2): In formula (2), Ψ W Indicates wind direction, V WE Indicates the east wind speed, V WN Indicates the north wind speed; if the future wind direction is defined as the wind direction, the wind direction Ψ is determined accordingly W as follows: When the east wind speed V WE <0, North wind speed V WN When <0, the wind direction is determined as Ψ W ; When the east wind speed V WE =0, north wind speed V WN When the east wind speed V WE >0, North wind speed V WN When <0, the wind direction is determined to be 360°+Ψ W ; When the east wind speed V WE <0, North wind speed V WN = 0, the wind direction is determined to be 90°; when the east wind speed V WE =0, north wind speed V WN = 0, the wind direction is determined to be calm; when the east wind speed V WE >0, North wind speed V WN =0, the wind direction is determined to be 270°; When the east wind speed V WE <0, North wind speed V WN When >0, the wind direction is determined to be 180°+Ψ W ; When the east wind speed V WE =0, north wind speed V WN >0, the wind direction is determined to be 180°; when the east wind speed V WE >0, North wind speed V WN When >0, the wind direction is determined to be 180°+Ψ W .

2. A method for determining wind speed and direction for complex helicopter scenes according to claim 1, characterized in that: The step one comprises: Step (11) obtaining the heading angle Ψ of the helicopter through a strapdown inertial navigation system; Step (12) obtains the ground speed of the helicopter relative to the earth through the strapdown inertial navigation system, and obtains the eastward speed V of the helicopter according to the ground speed E and northward velocity V N .

3. The method for determining wind speed and direction for complex helicopter scenes according to claim 1, characterized in that: The second step comprises: Step (21) obtaining the angle of attack α and the sideslip angle β of the helicopter through a strapdown inertial navigation system; Step (22) obtains the comprehensive true air speed V of the single-axis atmospheric machine through a strapdown inertial navigation system t , where the comprehensive true air speed V t Including longitudinal velocity component, transverse velocity component and normal velocity component; Step (23) calculates the comprehensive true air speed V obtained by the single-axis atmospheric engine according to the angle of attack α and the sideslip angle β. t The conversion expression is: In formula (3), represents the wind speed matrix, V t ×sin(β) represents the vertical axis velocity component, V t ×cos(α)×cos(β) represents the horizontal axis velocity component, -V t ×sin(α)×cos(β) represents the normal velocity component.

4. The method for determining wind speed and direction for a complex helicopter scene according to claim 1, characterized in that: In the formula (1) of step 3, Indicates the square of wind speed, wind speed V W The larger the wind direction W The smaller the calculation error.

5. The method for determining wind speed and direction for complex helicopter scenes according to claim 1, characterized in that: Also includes: Step 4: According to the error of wind speed and wind direction determined in step 3, the heading angle Ψ and the east wind speed V are dynamically adjusted. WE , North wind speed V WN , re-determine the wind speed and wind direction until the wind speed and wind direction are accurately determined.

6. A method for determining wind speed and direction for complex helicopter scenes according to claim 5, characterized in that: In the step 4, the step 3 determines the error of wind speed and wind direction, including: (1) The wind speed V determined in step 3 W When the wind direction is small, W The calculation error increases dramatically; (2) When the helicopter is flying backward, flying sideways, turning, climbing or descending, the wind speed V determined in step 3 is W and wind direction W Calculation errors occur during synchronization; (3) When the helicopter is flying at a low speed, the duration of the maneuvering flight is short, or before the maneuvering flight resumes high-speed forward flight, the wind direction Ψ determined in step 3 W An error occurred.

7. The method for determining wind speed and direction for complex helicopter scenes according to claim 5, characterized in that: In step 4, the heading angle Ψ and the east wind speed V are dynamically adjusted. WE , North wind speed V WN , re-determine the wind speed and direction until the wind speed and direction are accurate, including: (1) Determine whether condition 1 is met. If condition 1 is met, cache the current heading angle Ψ and eastward speed V of the helicopter every 1 second. E , northward speed V N , 1s average east wind speed V WE and north wind speed V WN , the maximum cache data is 30s; Substitute into formula (1) and formula (2) to determine the wind speed and direction; Among them, the condition 1 is: the helicopter meets the current ground speed> 36km / h and the comprehensive true air speed V in complex scenes at the same time. t >40km / h, the absolute value of (track angle - heading angle Ψ) <45°; (2) Starting from the time when the cached data is full for 30 seconds, determine whether condition 2 is met every 1 second. If condition 2 is met, cache the 30 seconds of east wind speed V WE and north wind speed V WN After taking the average value, it is recorded as the easterly wind speed and north wind speed If condition 2 is not met or the cached data is less than 30 seconds, the 1-second average east wind speed V WE and north wind speed V WN Assign value to east wind speed and north wind speed The east wind speed and north wind speed Substitute into formula (1) and formula (2) to determine the wind speed and direction; Among them, the condition 2 is: (a) the maximum cruising speed V of the helicopter within the current 30 seconds xmax and the minimum cruising speed V xmin The absolute value of the difference |ΔV x |≤20km / h; (b) The maximum heading value of the helicopter within the current 30s H max , minimum heading value H min The absolute value of the difference |ΔH|≤10°; (3) Starting from the time when the cached data is full for 30 seconds, determine whether condition 3 is met every 1 second. If condition 3 is met, cache the east wind speed V for 30 seconds. WE and north wind speed V WN After taking the average value, record the time of this calculation and the 30s average east wind speed 30s average north wind speed Current heading angle Ψ, current integrated true airspeed V t ; If the east wind speed and north wind speed If neither is substituted into formula (1) or formula (2) for calculation, then the east wind speed is East wind speed North wind speed =North wind speed If the east wind speed and north wind speed Substituting into formula (1) and formula (2) for calculation, the east wind speed is =East wind speed North wind speed =North wind speed The east wind speed and north wind speed Substitute into formula (1) and formula (2) to determine the wind speed and direction; Among them, the condition 3 is: (a) the maximum cruising speed V of the helicopter within the current 30 seconds xmax and the minimum cruising speed V xmin The absolute value of the difference |ΔV x |≤5km / h; (b) The maximum heading value of the helicopter within the current 30s H max , minimum heading value H min The absolute value of the difference |ΔH|≤3°.

8. The method for determining wind speed and direction for complex helicopter scenes according to claim 7, characterized in that: In step 4, adjust the heading angle Ψ and the east wind speed V WE , North wind speed V WN , until the wind speed and direction are determined accurately, including: (4) Select the current average easterly wind speed of the helicopter and north wind speed Substitute into formula (1) and formula (2) to determine the wind speed and direction; where the east wind speed is and north wind speed The expression is: In formula (4), the east wind speed and north wind speed The east wind speed is obtained by step 4 (3). and north wind speed Obtained by step 4 (2); (5) Select the helicopter's current 30-second average easterly wind speed and northerly wind speed after calibration compensation. and north wind speed Substitute into formula (1) and formula (2) to determine the wind speed and direction; (6) When condition 4 is met, the wind speed and direction determined by formula (1) and formula (2) remain unchanged; wherein condition 4 is: comprehensive true air speed V t ≤40km / h, or ground speed ≤36km / h, or the absolute value of the drift angle is >90°.

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