Dynamic and static combined test method for airflow field in take-off and landing related area of shipboard aircraft

Abstract

A dynamic and static combined test method for an airflow field in a take-off and landing related area of a shipboard aircraft comprises a dynamic test and a static test, and the dynamic test comprises the following steps: S1, arranging a Doppler coherent laser wind finding radar as a first radar on a deck in an area on one side of a ship bow, and scanning by adopting a multi-elevation PPI scanning mode; s2, a second radar is arranged on the second layer of a ship bridge in the middle of the ship, and a downward multi-pitch-angle PPI scanning mode is adopted; the static test comprises the steps that S3, a Doppler coherent laser wind finding radar is arranged on a center deck of a ship bow runway area, and an elevation PPI scanning mode is adopted for scanning; and S4, placing a plurality of vertical radars on a ship stern, and vertically and upwards scanning. According to the invention, high-precision and real-time three-dimensional measurement is carried out on the ocean wind field and wake flow around the ship, and a shipboard aircraft can be guided to take off and land in a real sense. According to the invention, a dynamic test and static test combined mode is designed especially for the situation that a radar cannot be installed on a deck of a landing area.

Description

Technical Field

[0001] The present invention belongs to the field of carrier-based aircraft takeoff and landing environment testing, and particularly relates to a method for testing the airflow field in the areas related to carrier-based aircraft takeoff and landing. Background Art

[0002] A carrier-based plane refers to an aircraft that takes off and lands on an aircraft carrier. When a carrier-based plane performs takeoff and landing operations on the relatively narrow and complexly moving deck of an aircraft carrier, in addition to itself, it is also comprehensively affected by many factors such as meteorological environment, ocean environment, and ship environment, such as marine environment, weather, sea conditions, electromagnetic environment, etc. According to statistics, the takeoff and landing stage is the main stage where safety accidents of carrier-based planes occur. Among them, the air flow field and ship movement in the ship environment are the key environmental factors threatening the safety of carrier-based aircraft takeoff and landing, and the air flow field is particularly prominent. Therefore, the research on the complex environment of carrier-based aircraft takeoff and landing has high significance.

[0003] Different carrier-based planes and ships must have different safety takeoff and landing envelopes and operation specifications. Generally, by solving the flight dynamics equations of carrier-based planes and combining the ship movement characteristics and flight deck flow field characteristics, a wind limit diagram is obtained. The ship air flow field is an important factor for the safe takeoff and landing of carrier-based planes. In order to effectively evaluate the takeoff and landing environment or ensure the precise control of carrier-based aircraft takeoff and landing, real-time or predicted data of the complex flow field in the takeoff and landing area are required.

[0004] The ship movement flow field usually includes stern airflow, deck wind, ship area turbulence, crosswind, etc. The research on the shipboard air flow field is a huge and complex systematic project. The current existing technologies mainly include wind tunnel tests, in-situ ship measurements, and CFD simulations. Due to the very complex superstructure on the ship deck, generally, both wind tunnel tests and CFD need to simplify the actual model, and the model accuracy has a great influence on the results. Therefore, although wind tunnel tests and CFD methods can obtain the flow field distribution of the ship under certain conditions to a certain extent, the actual situation of the ship is more complex, with higher dynamics and randomness, and it is difficult to accurately obtain the actual ship air flow field from the results of wind tunnel experiments and CFD simulations. Whether for wind tunnel simulations or CFD simulations, the wall boundary conditions have a great influence on the measurement results, and atmospheric boundary conditions need to be used. The velocity type distribution in the atmospheric boundary conditions of CFD and wind tunnel simulations also needs to be measured from in-situ ship measurements. Therefore, in-situ ship testing of the ship air flow field has important practical significance for studying the complex flow field of the ship, optimizing the ship model, optimizing the compatibility design of the ship and carrier-based aircraft, or providing data for the takeoff and landing of carrier-based aircraft to provide a reference for safety assessment, etc.

[0005] Conventionally, aircraft carriers mainly rely on the wind measurement equipment installed on the central mast of the island to measure the wind direction and speed. In addition, the wind direction and speed conditions for the safe takeoff and landing of carrier-based aircraft are all from the measurement results of the anemometer. Usually, the anemometer includes a wind cup, a wind measurement tower, a Doppler sound radar, a microwave radar, etc. However, due to the influence of the flow field around the flight deck of the aircraft carrier and the island structure (island) on the ship, there is a certain error between the wind field measured by the wind cup and the wind measurement tower installed in the eddy current area and the actual true wind, and it is difficult to ensure a fixed value. There are also defects such as over-high effect, susceptibility to weather, and difficulty in construction and movement. The detection range of the Doppler sound radar is limited, generally in the range of dozens of meters to hundreds of meters. The spatio-temporal resolution is generally 10 minutes and 10 meters, and its availability is particularly reduced at night or in high-altitude areas. In addition, the detection range of the sound radar is short outside the calibrated regional wind field. The "Doppler sound radar" and "microwave radar" can only detect the wind speed at different heights above the equipment and do not have the servo scanning function. Therefore, they cannot detect the wind in the glide path area or the three-dimensional wind field situation within the semicircle above the equipment. The non-coherent wind measurement lidar is relatively large in volume and is not suitable for the shipboard environment. Currently, SHOL designates safe operating conditions for the takeoff and landing of aircraft based on the wind speed and direction (WOD) on the deck measured by the anemometer on the ship and the experience of the pilot. Since the anemometer belongs to single-point measurement and cannot effectively represent the ocean wind field and wake around the ship, there may be a large difference from the actual wind speed situation. Under the condition of high wind speed, this requires high-precision measurement. The SHOL established by the anemometer may give incorrect instructions, further greatly increasing the danger of the landing of carrier-based aircraft. Therefore, there is currently a lack of detailed and accurate in-situ observation means to achieve the measurement of complex airflow environments to guide the safe takeoff and landing of carrier-based aircraft. Summary of the Invention

[0006] In order to achieve the measurement of complex airflow environments to guide the safe takeoff and landing of carrier-based aircraft, the present invention provides a method for testing the airflow field in the relevant area of carrier-based aircraft takeoff and landing. In particular, the present invention is applicable to the situation where a crosswind radar cannot be installed on the deck due to space limitations.

[0007] The specific technical solution is as follows:

[0008] A dynamic and static combined testing method for the airflow field in the relevant area of carrier-based aircraft takeoff and landing, characterized by including dynamic testing and static testing.

[0009] The dynamic testing includes:

[0010] S1, set a Doppler coherent lidar as the first radar on the deck in the area on one side of the bow of the ship. The first radar scans in a multi-elevation PPI scanning mode to obtain radial wind speed data at different azimuth angles and different elevation angles, and inversely calculates the radial data through the VAD algorithm to obtain the horizontal wind field situation at the height around the ship's deck.

[0011] S2. Install a Doppler coherent lidar on the second floor of the bridge in the middle of the ship as the second radar. Adopt a downward multi-elevation angle PPI scanning mode to scan downward to obtain the measurement of the influence area of the ship's wake. Invert the radial data through the VAD algorithm to obtain the horizontal wind field situation in the ship's stern wake area;

[0012] The static test includes:

[0013] S3. Install a Doppler coherent lidar on the central deck of the ship's bow runway area. Adopt an elevation angle PPI scanning mode to scan and obtain the radial wind speed data and horizontal wind field situation behind the ship's stern;

[0014] S4. Place several vertical radars behind the ship's stern and space them at certain intervals. Remove the optical wedge mirror. The lidar scans vertically upward to obtain the vertical wind speeds at multiple positions on the aircraft takeoff and landing route, and then combine them with the above-mentioned horizontal wind field situation to supplement the ship's wake data analysis report.

[0015] Preferably, the Doppler coherent lidar is WindPrint S4000 or S10000. The equipment body occupies at least an area of 1m×1m, and there is no obstruction in the scanning path; the equipment power supply is AC 220V, and the reserved power is 800W; the vertical radar is WindPrint V300.

[0016] Preferably, in step S1, the default 0° direction of the first radar is consistent with the ship's bow direction, and it scans a 180° range in a multi-elevation angle PPI scanning mode from 0° to 4°.

[0017] Preferably, in step S2, the default 0° direction of the second radar is consistent with the ship's bow direction, and it adopts a multi-elevation angle PPI scanning mode from 184° to 180° to scan at least a 40° range downward to obtain the measurement of the influence area of the ship's wake.

[0018] More preferably, scan a 135° area downward.

[0019] Preferably, in step S3, it scans a 160° range in an elevation angle PPI scanning mode of 1° and 3°.

[0020] Preferably, in step S4, set 3 vertical radars to obtain the vertical wind speeds at 3 positions on the aircraft takeoff and landing route.

[0021] Preferably, it includes a combined navigation device that combines inertial navigation and satellite positioning. The inertial navigation system includes a gyroscope and an accelerometer. The main box of the combined navigation device is installed on the surface of the installation platform of the Doppler coherent lidar.

[0022] Preferably, two horizontal crossbars of inertial navigation antennas are installed on the fence beside the Doppler coherent lidar wind measurement radar, and the length of the crossbars is 2m.

[0023] The beneficial effects of the present invention are as follows:

[0024] The Doppler coherent lidar wind measurement radar selected in the present invention has achieved an all-fiber design, has low requirements for lasers and the environment, has high system stability, small volume, small blind area, and high spatio-temporal resolution. Because it has a scanning function, it can realize three-dimensional real-time detection of the airflow changes on the aircraft takeoff and landing routes.

[0025] Compared with other wind field measurement methods, the lidar measurement scheme can not only achieve high-resolution real-time three-dimensional wind field detection, but also avoid the influence of other detection devices on the flow field itself due to its small size and portability. The present invention is aimed at the characteristics of the small spatial scale and rapid temporal scale change of the ocean wind field and wake around the ship, as well as the particularity of the shipborne platform and application environment, and has the following characteristics:

[0026] 1. It is applicable to harsh environments such as high mobility, high temperature, high humidity, and high salinity of shipborne platforms;

[0027] 2. In view of the complex change of the relationship between the Doppler spectrum and the wind speed caused by the rapid change of the attitude of the highly mobile shipborne platform, the airflow field test can quickly, robustly, and efficiently measure the wind speed and direction;

[0028] 3. An attitude and motion measurement device combining an inertial navigation unit IMU and a satellite navigation unit is adopted, which has adaptive attitude measurement and motion compensation, and can measure the real-time and accurate complete ocean wind field, and can quickly and stably measure the motion and rotation of the shipborne radar in all directions for a long time;

[0029] 4. It has the ability of low blind area, high range resolution, and fast scanning, and can measure the real-time distribution of the ship wake.

[0030] The present invention conducts high-precision, real-time three-dimensional measurement of the ocean wind field and wake around the ship, which is of great significance for establishing an effective SHOL and can truly guide the takeoff and landing of shipborne aircraft. Moreover, the in-situ test of the ship airflow field also has important practical significance for studying the complex flow field of the ship, optimizing the ship model, optimizing the compatibility design of the ship and the shipborne aircraft, or providing data for the takeoff and landing of the shipborne aircraft to provide a reference for safety assessment, etc.

[0031] The present invention specifically aims at the situation where, due to limited on-site conditions of the ship, the radar cannot be installed on the landing area deck, and the radars on the bridge and the bow deck cannot measure the vertical wind speed in the area behind the stern of the ship. The measurement scheme is divided into two parts: one part is the dynamic measurement of the wind field around the ship by the lidar following the movement of the ship during the ship's navigation; the other part is the static measurement of the wind field around the ship during the ship's docking. By capturing the wind field data under the same working conditions during the static measurement to supplement the dynamic measurement data, the analysis of the stern airflow field is completed. Description of the Drawings

[0032] Figure 1 Schematic diagram of the installation of the Doppler coherent lidar for Example 1;

[0033] Figure 2 Schematic diagram of the radial wind speed map of Radar No. 1 for Example 1;

[0034] Figure 3 Schematic diagram of the static mode for Example 1;

[0035] Figure 4 Schematic diagram of the installation of the Doppler coherent lidar and the automatic weather station for Example 2. Detailed Implementation Manner

[0036] The present invention will be further described below with reference to the drawings and embodiments.

[0037] Example 1

[0038] A dynamic and static combined test method for the airflow field in the relevant area of carrier aircraft takeoff and landing in this embodiment divides the measurement scheme into two parts: one part is the dynamic measurement of the wind field around the ship by the lidar following the movement of the ship during the ship's navigation; the other part is the static measurement of the wind field around the ship during the ship's docking. By capturing the wind field data under the same working conditions during the static measurement to supplement the dynamic measurement data, the analysis of the stern airflow field is completed.

[0039] Specifically, it is preferably to use the WindPrint S1000 coherent Doppler wind lidar system, which is a small, fully automatic, and environmentally electromagnetic interference-free Doppler wind lidar, capable of realizing all-weather and uninterrupted three-dimensional low-altitude wind field detection. By configuring a multi-lidar networking observation service software platform, it can realize the networking detection and service analysis functions of wind profiles, vertical airflows, and PPI / RHI / horizontal wind fields. The system adopts eye-safe near-infrared laser detection technology, has high time resolution, spatial resolution, and accuracy, and can realize fully automatic unattended observation of the atmospheric three-dimensional wind field silently and safely. The system consists of a small fully automatic boundary layer Doppler wind lidar, a ground meteorological element system, a communication transmission system, a power supply system, etc.

[0040] When the Doppler coherent lidar for wind measurement works, the laser emits laser pulses with a wavelength of 1550 nm into the atmosphere at a certain repetition rate through an optical transmitting system. During the propagation of the laser pulses in the atmosphere, they collide with aerosol particles, scatter, and undergo frequency changes (i.e., Doppler frequency shifts). The backscattered light among them carries the Doppler frequency shift information of the aerosol particles and is received by the optical receiving system of the lidar. The light received by the receiving system and the local oscillator light of the laser generate a difference frequency signal (i.e., the Doppler frequency shift amount of the aerosol particles) after coherent mixing. This signal can obtain the radial wind speed of the aerosol particles (i.e., the wind) after photoelectric conversion and processing. The distance of the detection position can be calculated based on the time of the received signal and the speed of light.

[0041] By analyzing the time delay and frequency offset of the echo signal, the lidar can determine the velocity of the aerosol particles, and thus infer the wind speed and wind direction in the atmosphere. In this way, the data of wind speed and wind direction at different heights in the atmosphere can be obtained in real time, so as to generate wind profile diagrams and other related application products.

[0042] The scanning mode of the Doppler coherent lidar for side wind measurement used in the present invention:

[0043] The servo scanning system of the Doppler coherent lidar for side wind measurement uses closed-loop control to eliminate the accumulated motion error and ensure that the pointing accuracy is always stable. The horizontal scanning range of the servo scanning system is 0 - 360°, and the pitch scanning range is -10 - 190°. Different scanning modes can be adopted according to different test requirements, including PPI / RHI / DBS / VAD / CAPPI / LOS / script programming (freely combining any two or more scanning modes, formulating specific scanning modes), etc., fully meeting the user's needs.

[0044] (1) DBS scanning mode

[0045] To obtain the vector wind speed, it is necessary to use the laser beam scanning technology to direct the laser beam to at least two different directions. The laser beam can be directed to the zenith direction (vertical z direction), the oblique east direction (x direction), and the due north direction (y direction), and vector synthesis is performed to calculate the actual vector wind speed V.

[0046] (2) PPI mode scanning mode

[0047] The PPI scanning mode is that the radar servo fixes the pitch angle, and the laser beam obtains the radial wind speed data in the scanning mode of azimuth angle transformation. The PPI scanning mode can obtain the radial wind speed, speed spectrum width, spectrum intensity, and signal-to-noise ratio information of each range bin. The radial wind speed refers to the wind speed of the projection of the actual wind field in the direction indicated by the radar beam at a certain time. The radial wind speed at each distance is not the actual wind speed at that point, but the component of the actual three-dimensional wind field in the beam direction. The horizontal wind speed is much greater than the vertical wind speed, and it is impossible to accurately calculate the vertical wind speed from the radial wind speed. The vertical speed must be vertically upward to accurately measure the vertical wind speed by scanning.

[0048] In addition, if the azimuth angle range of PPI scanning is large enough, according to the wind speed inversion algorithm in the VAD algorithm, the wind speed and wind direction of each range gate in some areas within the PPI scanning range can be calculated; if the scanning range covers 360°, the wind direction and wind speed of the full azimuth range can be calculated.

[0049] (3) Vertical air flow scanning mode

[0050] The vertical air flow is the radial wind speed value of each range bin measured by the radial beam of the lidar vertically at the zenith (directly above the radar), without inversion.

[0051] The lidar parameters used in this embodiment:

[0052] Lidar WindPrint S10000 technical parameters

[0053]

[0054]

[0055] The specific test process is as follows:

[0056] Dynamic test:

[0057] According to the installation position determined on site, deploy two sets of S10000 coherent wind lidars to measure the three-dimensional wind field around the ship, mainly including the wind field above the deck, the ship wake, and the wind field around the ship. The installation schematic diagram is as Figure 1 shown:

[0058] The first radar is located on the deck in the right front area of the ship's bow. The default 0° direction of the lidar is consistent with the ship's bow direction, and it uses the PPI scanning mode with multiple elevation angles from 0° to 4° to scan approximately 180° range ( Figure 1 red area). The radial wind speed data at different azimuth angles and different elevation angles in this area can be obtained, and the drawn radial wind speed map Figure 2 can intuitively show the horizontal wind field above the ship's deck and the wind field around the ship.

[0059] The VAD algorithm can be used to invert radial data to obtain the horizontal wind field conditions around the ship deck. If the measurement effect is not obvious, the scanning range and scanning pitch angle can be expanded to obtain the horizontal wind field conditions around the ship in a larger range.

[0060] The second radar is located on the second floor of the bridge (such as Figure 1 As shown in the figure, the default 0° direction of the laser radar is consistent with the bow direction. If there is a railing blocking it, the laser radar scanner head can avoid the railing by adjusting the scanning angle. Considering that the laser radar is located on the second floor of the bridge, about 3m above the deck plane, in order to better capture the trajectory of the stern airflow, a 184° to 180° (-4° to 0) multi-pitch angle PPI scanning mode is used to scan a 40° range ( Figure 1 If the measurement effect is not obvious, you can expand the scanning range and scan the 135° area ( Figure 1 Green area), get a clear view of the wake. At the same time, the VAD algorithm can be used to invert radial data to obtain the horizontal wind field conditions in the wake area at the stern of the ship.

[0061] A PPI scan behind the stern of the ship can obtain the radial wind speed data of the path lidar at a 3° elevation angle at the entrance of the glide path, and analyze the changes in the top wind of the glide path with different wind directions.

[0062] All LiDAR data products are generated based on radial wind speed data. Radial wind speed refers to the wind speed projected in the direction of the radar beam at a certain moment in time. The radial wind speed at each distance is not the actual wind speed at that point, but the component of the actual three-dimensional wind field in the direction of the beam.

[0063] The elevation angle measured in this scheme is relatively low, and the horizontal wind speed is much greater than the vertical wind speed. The accurate vertical wind speed cannot be calculated using the radial wind speed. The vertical speed must be measured by scanning vertically upwards. The vertical wind speed 500m behind the stern cannot be obtained by low-elevation-angle PPI scanning. Therefore, a static test was designed based on the dynamic test.

[0064] Static test:

[0065] Due to location limitations, the dynamic test was unable to obtain the wind field information of the airflow at the stern of the ship. The static test mainly tested the wind field information behind the stern of the ship and supplemented the ship wake data analysis report.

[0066] When the ship is docked, the vertical wind data on the take-off and landing routes is captured using one scanning laser radar WindPrint S10000 (radar No. 1) and three vertical laser radars WindPrint V300 (radar No. 2, radar No. 3, radar No. 4). Figure 3 shown.

[0067] The No. 1 radar is installed on the central deck of the bow runway area. By default, the 0° direction of the lidar is consistent with the direction of aircraft takeoff and landing navigation. It uses a PPI scanning mode with elevation angles of 1° and 3° to scan a range of approximately 160° ( Figure 3 green area) to obtain the radial wind speed data and horizontal wind field conditions behind the stern. (Since the wind speed is relatively high during dynamic observation and combined with the ship's navigation speed, the effect of PPI scanning for dynamic testing will be more ideal than static observation. The data here is only used for verification and comparison with the data of the No. 2 radar in dynamic testing.)

[0068] The No. 2 radar, No. 3 radar, and No. 4 radar are respectively placed at positions 150m / 300m / 500m behind the stern (adjustable according to the on-site position).

[0069] The principle of the vertical radar WindPrint V300 is to use a scanning mirror system (optical wedge mirror) to change the elevation angle of the light output direction (fixed elevation angle of 60°). Considering that the purpose of this measurement is to measure vertical wind speed data, the optical wedge mirror is removed, and the lidar will scan vertically upward. The three radars can obtain the vertical wind speed at three positions on the aircraft takeoff and landing route.

[0070] Due to the measurement blind area existing in the principle system of the lidar, the vertical radar can collect the vertical wind speed in the range of 40m - 300m. By combining it with the horizontal wind field data measured by the scanning radar, the analysis report of the ship wake flow can be supplemented.

[0071] Embodiment 2

[0072] As Figure 4 shown, in this embodiment, 4 automatic weather stations are used to measure the horizontal wind speed and direction in each area of the deck as a supplement to the horizontal wind field on the ship deck during static measurement, so as to increase the measurement equipment as much as possible to obtain more deck wind (near-surface wind).

[0073] The above specific implementation manners are the preferred embodiments of the present invention and cannot limit the present invention. Any change or other equivalent replacement method that does not deviate from the technical solution of the present invention is included in the protection scope of the present invention.

Claims

1. A dynamic and static combined test method for the airflow field in the area related to take-off and landing of carrier-based aircraft, characterized in that Including dynamic test and static test, The dynamic test includes: S1, a Doppler coherent laser wind measuring radar is set on the deck in the bow area as the No. 1 radar, and the No. 1 radar adopts a multi-elevation PPI scanning mode to obtain radial wind speed data at different azimuths and elevations, and the radial data is inverted by the VAD algorithm to obtain the horizontal wind field conditions around the height of the ship deck; S2, a Doppler coherent laser wind measurement radar is set up on the second floor of the bridge in the middle of the ship as the second radar, using a downward multi-pitch angle PPI scanning mode to obtain the measurement of the impact of the ship wake area, and the VAD algorithm is used to invert radial data to obtain the horizontal wind field conditions of the stern wake area; The static test includes: S3, a Doppler coherent laser wind measuring radar is installed on the central deck of the bow runway area, and the elevation PPI scanning mode is used to obtain the radial wind speed data and horizontal wind field conditions behind the stern of the ship; S4, place several vertical radars behind the stern of the ship and space them at a certain distance, remove the optical wedge mirror, and scan the laser radar vertically upward to obtain the vertical wind speed at multiple locations of the aircraft take-off and landing routes, and then combine it with the horizontal wind field conditions to supplement the ship wake data analysis report.

2. The method according to claim 1, characterized in that The Doppler coherent laser wind measurement radar is WindPrintS4000 or S10000, the device body occupies an area of ​​at least 1m×1m, and there is no obstruction in the scanning path; the device is powered by AC220V, and the power reserved is 800W; the vertical radar is WindPrint V300.

3. The method according to claim 1, characterized in that In step S1, the No. 1 radar assumes that the 0° direction is consistent with the bow direction, and scans a 180° range in a 0° to 4° multi-elevation PPI scanning mode.

4. The method according to claim 1, characterized in that In step S2, the second radar defaults to the 0° direction being consistent with the bow direction, and adopts a 184° to 180° multi-pitch angle PPI scanning mode to scan at least 40° to obtain measurements of the impact of the ship wake area.

5. The method according to claim 4, characterized in that Scan the area of ​​135°.

6. The method according to claim 1, characterized in that In step S3, a 160° range is scanned in a PPI scanning mode with elevation angles of 1° and 3°.

7. The method according to claim 1, characterized in that In step S4, three vertical radars are set up to obtain the vertical wind speeds at three locations of the aircraft take-off and landing routes.

8. The method according to claim 1, characterized in that The invention comprises a combined navigation device combining an inertial navigation system with satellite positioning, wherein the inertial navigation system comprises a gyroscope and an accelerometer, and a main box of the combined navigation device is installed on the surface of the installation platform of the Doppler coherent laser wind measurement radar.

9. The method according to claim 8, characterized in that Two inertial navigation antenna horizontal cross bars are installed on the fence next to the Doppler coherent laser wind measurement radar mine.

10. The method according to claim 9, characterized in that The crossbar is 2m long.

Images