Method for estimating parachute opening point position of meteorological and sounding rocket parachute

Abstract

The invention provides a method for estimating a parachute opening point position of a meteorological and sounding rocket parachute. The method comprises the following steps: step 1, setting a detection target point of a meteorological and sounding rocket as an initial parachute opening point; step 2, presetting an initial launching point, an initial launching angle and a maximum parachute opening position of the meteorological sounding rocket based on the initial parachute opening point; step 3, inputting the initial launching point, the initial launching angle and the maximum parachute opening position into an iteration unit, continuously iterating by the iteration unit, and outputting an estimated parachute opening point; 4, determining a planned launching point and a planned launching angle for launching the meteorological and sounding rocket based on the estimated parachute opening point; and 5, determining a rocket flight path according to the planned launching point and the planned launching angle, and determining a parachute opening point position based on the rocket flight path. According to the method, the flight process of separating the load to the parachute opening section is simplified into inertial motion under the action of gravity, the inflation process of the parachute is ignored, the maximum parachute opening height is estimated by directly utilizing a dynamic pressure formula, so that the relative position of the parachute opening point is estimated, and the estimation process is simple and convenient.

Description

Technical Field

[0001] The invention belongs to the technical field of meteorological data collection, and in particular relates to a method for estimating the position of a parachute opening point of a meteorological sounding rocket parachute. Background Art

[0002] Meteorological sounding rockets are very important means of in-situ measurement of near-space atmospheric environment. They use uncontrolled rockets to send payloads (sondes and parachute packs) to an altitude of more than 70 km. Their working principle is: after the rocket is ignited, the main engine and booster are ignited at the same time to generate a predetermined thrust. Under the action of the thrust, the rocket leaves the launch rail. After leaving the orbit, the rocket continues to rise along the predetermined trajectory under the action of the thrust until the main engine is shut down and the rocket reaches the maximum speed. Then the rocket continues to rise by its inertia until it is close to the apex of the trajectory. The rocket's flight altitude is about 70 km. The timing mechanism on the rocket issues a command, and the ejection separation system ignites to generate ejection thrust, so that the payload (sonde, parachute) is separated from the rocket body recovery cabin and a fixed relative separation speed is obtained. Subsequently, the payload continues to climb to the highest point by inertia, and then begins to fall, with a trajectory similar to a parabola. During the falling process, when the air dynamic pressure reaches the parachute opening condition, the parachute opens to provide lift and decelerate rapidly. The sonde falls slowly under its traction and gradually stabilizes. During the descent, the temperature sensor measures the atmospheric temperature and the pressure sensor measures the atmospheric pressure, which are then transmitted to the ground via a transmitter. After being processed by the data processing system, the atmospheric temperature, pressure, density, wind speed and direction data can be obtained.

[0003] During the descent of the sonde and parachute, the atmospheric temperature, air pressure, density, wind speed and direction data of the near-space within the 20km to 60km range of the descent area are detected in situ. Near-space refers to the Earth's atmosphere between 20km and 100km in altitude. The atmospheric parameters such as atmospheric temperature, air pressure, density, wind speed and wind direction in near-space have important applications in spacecraft flight tests. At present, there are three types of detection methods for near-space atmospheric parameters: the first type is space-based detection, mainly atmospheric detection satellites; the second type is ground-based detection, mainly medium-frequency radar, MST radar, laser radar, etc.; the third type is in-situ detection, mainly including meteorological sounding rockets and sounding balloons. Among the three types of detection methods, both space-based detection and ground-based detection use certain physical principles to invert and obtain atmospheric parameters, while in-situ detection uses sensors to directly detect the passing atmosphere. Therefore, in-situ detection has an inherent advantage in credibility.

[0004] Balloon sounding is relatively mature in China, but the height generally only reaches about 30km, and special large balls can reach about 45km. Meteorological sounding rockets can reach a height of 60km, meeting the needs of specific scenarios such as aerospace.

[0005] Normally, the flight process of a meteorological sounding rocket is as follows: Figure 1As shown in the figure, after the rocket ignites and takes off, it flies without control. At the preset separation time, the payload separates from the rocket body. After separation, the payload still flies by inertia, and the trajectory is similar to a parabola. It first climbs to the top and then descends. During the descent, the speed increases. When the dynamic pressure of the parachute is met, the parachute opens. After rapid deceleration, the parachute slowly falls with the wind carrying the sonde. During the descent, the atmospheric temperature, pressure, density, wind speed and direction on the falling trajectory are measured, and the data is sent to the ground receiving system.

[0006] During the descent, the timely opening of the parachute is very important for the success of the detection, especially when the descent speed is very fast. If the parachute is not opened normally, the atmospheric fluid state detected by the sensor of the radiosonde is complex, and the sensor measurement error is large, resulting in detection failure. At present, most meteorological sounding rockets use passive parachute opening, that is, during the descent of the payload (sonde, parachute), as the altitude decreases, the speed increases, and the atmospheric density increases. When the critical condition is reached, the parachute opens naturally under the action of the internal and external pressure difference. The entire flight and opening process of the meteorological sounding rocket is uncontrolled, that is, the payload flight before the parachute opens is uncontrolled, and there is no need for manual intervention in the falling speed of the payload. The opening process of the parachute is uncontrolled and passive. Summary of the invention

[0007] The purpose of the present invention is to solve the shortcoming of the uncontrolled opening process of the parachute in the prior art, and to provide a method for estimating the opening point position of a meteorological sounding rocket parachute, which simplifies the flight process from load separation to the opening section into inertial motion under the action of gravity, ignores the inflation process of the parachute, and directly uses the dynamic pressure formula to estimate the maximum opening height, thereby estimating the relative position of the opening point, and the estimation process is simple and convenient.

[0008] To achieve the above purpose, the technical solution provided by the present invention is:

[0009] The present invention provides a method for estimating the position of a parachute opening point of a meteorological sounding rocket parachute, comprising:

[0010] Step 1: setting the detection target point of the meteorological sounding rocket as the initial parachute opening point;

[0011] Step 2: presetting the initial launch point, initial launch angle and maximum parachute opening position of the meteorological sounding rocket based on the initial parachute opening point;

[0012] Step 3: inputting the initial launch point, the initial launch angle and the maximum parachute opening position into an iteration unit, and the iteration unit continuously iterates to output an estimated parachute opening point;

[0013] Step 4: determining a planned launch point and a planned launch angle for launching a meteorological sounding rocket based on the estimated parachute opening point;

[0014] Step 5: Determine the rocket flight trajectory according to the planned launch point and the planned launch angle, and determine the parachute opening point position based on the rocket flight trajectory.

[0015] As a further limitation of the present invention, the step 1 comprises:

[0016] Determine the detection target point, allow the meteorological sounding rocket to enter the expected detection target area, and the parachute's falling speed is within the speed allowed by the sensor carried by the meteorological sounding rocket;

[0017] Based on the detected target point, determining the separation point of the meteorological sounding rocket and the rocket body recovery capsule;

[0018] Determine the trajectory vertex of the meteorological sounding rocket's climbing process according to the separation point;

[0019] The initial parachute opening point of the meteorological sounding rocket during its descent from the apex of the trajectory is determined.

[0020] As a further limitation of the present invention, the process of determining the separation point includes:

[0021] (1) After the main engine that propels the meteorological sounding rocket to ascent is shut down, determine the maximum speed of the meteorological sounding rocket as it continues to ascend along the planned trajectory;

[0022] (2) determining a separation point at which the meteorological sounding rocket separates from the meteorological sounding payload based on the maximum speed during the continued ascending flight; wherein the meteorological sounding payload includes a sonde and a parachute;

[0023] The process of determining the trajectory vertex includes:

[0024] (1) Determine the horizontal flight speed V0 of the meteorological sounding rocket xy , vertical flight speed V0 z and the flight angle of attack φ, and the relative velocity ΔV at separation;

[0025] (2) Calculate the horizontal velocity V of the meteorological sounding payload after the separation point xy and vertical velocity V z ,in:

[0026] The angle γ between the flight speed direction of the meteorological sounding payload and the horizontal plane is:

[0027] The horizontal velocity V of the meteorological sounding load xy =V xy =V0 xy +ΔVcos(φ+γ);

[0028] The vertical velocity V of the meteorological sounding load z=V z =V0 z +ΔVsin(φ+γ).

[0029] As a further limitation of the present invention, the process of determining the initial parachute opening point includes:

[0030] (1) Determine that the meteorological sounding payload moves inertially under the action of gravity after the separation point, and continues to move horizontally according to V xy Uniform motion, subject to the force of gravity in the vertical direction;

[0031] (2) Determine the time t1 of the meteorological sounding load rising from the separation point to the top as: Wherein, g represents the acceleration of gravity; the height H of the meteorological sounding load from the separation point to the top dd for: Among them, H fl represents the height of the separation point, ΔH1 represents the climbing height;

[0032] (3) Establish the function of the flight speed V and the height H of the meteorological sounding payload during its descent from the vertex under the action of gravity

[0033] Obtain the relationship between flight speed, flight time and altitude during descent from the apex;

[0034] (4) Establish a function of parachute opening dynamic pressure and altitude, and determine the parachute opening altitude based on the parachute opening dynamic pressure.

[0035] As a further limitation of the present invention, in the function of establishing the dynamic pressure and height of the parachute, the function expression of the dynamic pressure P and the height H of the parachute is:

[0036] Among them, V represents the parachute flight speed, Atmos (H) represents the atmospheric density;

[0037] The minimum parachute opening dynamic pressure is determined, and the height that satisfies the minimum parachute opening dynamic pressure is determined as the maximum parachute opening height.

[0038] As a further limitation of the present invention, the step 2 comprises:

[0039] Based on the detection target point in step one, initial values ​​are set for the launch point and launch angle of the meteorological sounding rocket, and based on the initial values, the separation point position and speed of the meteorological sounding rocket climbing in the initial state are determined.

[0040] As a further limitation of the present invention, the preset maximum parachute opening position in step 2 includes:

[0041] The minimum parachute opening dynamic pressure of the meteorological sounding rocket is determined based on the function expression of the parachute dynamic pressure P and the height H, and the maximum parachute opening position is preset based on the height that meets the minimum parachute opening dynamic pressure.

[0042] As a further limitation of the present invention, the step three comprises:

[0043] Inputting the initial launch point, the initial launch angle and the maximum parachute opening position determined in step 2 into an iteration unit of a detection mission planning system;

[0044] The iteration unit adjusts the position and the launch angle of the launch point, and changes the position and the speed of the separation point based on the position and the launch angle of the launch point;

[0045] The iterative unit continuously iteratively adjusts the position and the launch angle of the launch point until the parachute opening point is close to the detection target point, and outputs the estimated parachute opening point.

[0046] As a further limitation of the present invention, the step 4 comprises:

[0047] Based on the estimated parachute opening point determined in step 3, the launch point position and the launch point angle in the state of the estimated parachute opening point in step 3 are determined as the planned launch point and the planned launch angle.

[0048] As a further limitation of the present invention, the step five comprises:

[0049] Determine the flight trajectory of the meteorological sounding rocket according to the planned launch point and the planned launch angle determined in step 4;

[0050] The meteorological sounding rocket flies along the flight trajectory, and the final parachute opening point is close to the detection target point, so that after the parachute opens, it slowly descends with the sonde to detect atmospheric parameters.

[0051] The advantages of the present invention are:

[0052] 1. Based on the characteristics of simple flight process, small payload volume and low atmospheric density at the parachute opening point of meteorological sounding rocket, the present invention ignores the atmospheric resistance effect before parachute opening and simplifies the flight process from payload separation to parachute opening section into inertial motion under gravity.

[0053] 2. The present invention takes into account that the parachute opening speed is relatively fast, and therefore ignores the parachute inflation process, and directly uses the dynamic pressure formula to estimate the maximum parachute opening height.

[0054] 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

[0055] 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:

[0056] Figure 1 : A flow chart of a method for estimating the position of a parachute opening point of a meteorological sounding rocket provided by the present invention;

[0057] Figure 2 : Illustration of the flight process of the meteorological sounding rocket provided by the present invention;

[0058] Figure 3 : A vector diagram of the load velocity at the separation moment of the meteorological sounding rocket provided by the present invention;

[0059] Figure 4 : Schematic diagram of the flight of the meteorological sounding rocket after payload separation provided by the present invention. DETAILED DESCRIPTION

[0060] 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.

[0061] Since the planning goal is to make the parachute opening point as close as possible to the specified detection target point when planning the meteorological detection mission, the planning result is to determine the launch point position and the launch angle. When planning the meteorological detection mission in the embodiment of the present invention, (1) the detection target point is set as the parachute opening point, that is, the initial parachute opening point of the embodiment of the present invention. (2) Based on the initial value of the launch point, the initial value of the launch angle, the separation point position and the separation point speed, the meteorological detection mission is simulated under the initial conditions to estimate the maximum parachute opening height, that is, the maximum parachute opening position of the embodiment of the present invention. (3) The task planning is continuously adjusted and iterated until the parachute opening point position is close to the detection target point, and the estimated parachute opening point of the embodiment of the present invention is obtained. (4) After completing the preliminary task planning and determining the launch point position and launch angle of the meteorological sounding rocket, the rocket flight trajectory can be determined, and the parachute opening position when simulating the meteorological detection mission can be determined, that is, the parachute opening point position of the embodiment of the present invention.

[0062] See also Figure 1 The embodiment of the present invention provides a method for estimating the position of the parachute opening point of a meteorological sounding rocket parachute, comprising the following steps:

[0063] Step 1: Set the detection target point of the meteorological sounding rocket as the initial parachute opening point.

[0064] The above step 1 of the embodiment of the present invention includes:

[0065] Determine the detection target point, and after the meteorological sounding rocket enters the expected detection target area, the parachute's falling speed is within the speed allowed by the sensor carried by the meteorological sounding rocket;

[0066] Based on the detected target point, determine the separation point between the meteorological sounding rocket and the rocket body recovery capsule;

[0067] Determine the trajectory apex of the meteorological sounding rocket's climbing process according to the separation point;

[0068] Determine the initial parachute opening point of the meteorological sounding rocket during its descent from the trajectory apex.

[0069] The process of determining the separation point in the embodiment of the present invention includes:

[0070] (1) After the main engine that propels the meteorological sounding rocket to ascent is shut down, determine the maximum speed of the meteorological sounding rocket as it continues to ascend along the planned trajectory;

[0071] (2) Determine the separation point of the meteorological sounding rocket from the meteorological sounding payload based on the maximum velocity during the continued ascent flight; the meteorological sounding payload includes the sonde and the parachute;

[0072] The process of determining the trajectory vertex includes:

[0073] (1) Determine the horizontal flight speed V0 of the meteorological sounding rocket xy , vertical flight speed V0 z and the flight angle of attack φ, and the relative velocity ΔV at separation;

[0074] (2) Calculate the horizontal velocity V of the meteorological sounding payload after the separation point xy and vertical velocity V z ,in:

[0075] The angle γ between the flight speed direction of the meteorological sounding payload and the horizontal plane is:

[0076] Horizontal velocity V of meteorological sounding payload xy =V xy =V0 xy +ΔVcos(φ+γ);

[0077] Vertical velocity V of meteorological sounding payload z =V z =V0 z +ΔVsin(φ+γ);

[0078] The process of determining the initial parachute opening point includes:

[0079] (1) Determine the inertial motion of the meteorological sounding payload from the separation point under the action of gravity, and continue to move horizontally according to V xy Uniform motion, subject to the force of gravity in the vertical direction;

[0080] (2) The time t1 for the meteorological sounding load to rise from the separation point to the top is determined as: Where g represents the acceleration of gravity; the height H of the meteorological sounding load from the separation point to the top dd for: Among them, H fl represents the height of the separation point, ΔH1 represents the climbing height;

[0081] (3) Establish the function of the flight speed V and the height H of the meteorological sounding payload during its descent from the vertex under the action of gravity

[0082] Obtain the relationship between flight speed, flight time and altitude during descent from the apex;

[0083] (4) Establish a function of parachute opening dynamic pressure and altitude, and determine the parachute opening altitude based on the parachute opening dynamic pressure.

[0084] In the above-mentioned function of establishing the dynamic pressure and height of the parachute opening in the embodiment of the present invention, the function expression of the dynamic pressure P and the height H of the parachute is:

[0085] Among them, V represents the parachute flight speed, Atmos (H) represents the atmospheric density;

[0086] The minimum parachute opening dynamic pressure is determined, and the altitude that meets the minimum parachute opening dynamic pressure is determined as the maximum parachute opening altitude.

[0087] In practical applications, the embodiment of the present invention uses the velocity vector before load separation, the separation relative velocity, and the angle of attack to calculate the velocity vector after load separation. Since meteorological sounding rockets are generally equipped with flight trajectory calculation software, the rocket's mass, propellant mass, specific impulse, launch angle and other parameters are used to calculate the rocket flight parameters based on the aerodynamic model. The rocket flight horizontal velocity V0 can be obtained from the rocket flight trajectory calculation software. xy 、Vertical speed V0 z , flight angle of attack φ, the relative speed ΔV at separation is the design constant, and the horizontal speed V after separation can be calculated xy , vertical speed V z For the load velocity vector at the moment of separation, please refer to Figure 3 .

[0088] After the load is separated, the embodiment of the present invention is approximately in inertial motion, and the initial state of inertial motion can be obtained through the above steps.

[0089] See also Figure 4, the height and time of the load inertial climbing to the top under the action of gravity after separation of the embodiment of the present invention, the calculation process includes: the payload of the meteorological sounding rocket is in the stage from separation to parachute opening, the parachute has not yet opened, and is connected to the sonde through the parachute rope in the form of a parachute bag, and the shape of the parachute bag and the sonde are both columnar. During the flight, no matter what the flight attitude of the load is, its resistance cross-section is very small, and the atmospheric density above 60km is very low, so the atmospheric resistance of the load is very small. Therefore, between separation and parachute opening, the effect of atmospheric resistance can be temporarily ignored, and this section of the flight process is simplified to inertial motion under the action of gravity. Continue in the horizontal direction according to V xy Uniform motion, only gravity acts in the vertical direction, see the flight diagram Figure 1 and Figure 4 .

[0090] The function of the speed V and the height H in the embodiment of the present invention is established by:

[0091] Establish the function of speed and height when the load descends from the vertex under the action of gravity. The vertical direction from the vertex to the parachute opening point is approximately a free fall motion. The falling time from the vertex to the height H is: The load is from the vertex H dd The vertical velocity when falling to height H is: The total speed at height H is: Where V xy is the horizontal velocity of the load after separation, and the function of the velocity V and the height H during the descent from the vertex is obtained as follows:

[0092]

[0093] In the formula, except H, other quantities are obtained by the flight trajectory calculation software or are constants: V0 xy V0 is the horizontal speed of the rocket before separation, z is the vertical velocity of the rocket at the moment before separation, φ is the rocket flight attack angle at the moment before separation, ΔV is the relative velocity at separation, g is the gravitational acceleration at that height, H fl The embodiment of the present invention uses a simple motion equation to describe the flight process from the load separation to the parachute opening stage, and obtains the relationship between the load flight speed, flight time and altitude.

[0094] The process of establishing the function of the parachute opening dynamic pressure and the height in the embodiment of the present invention includes:

[0095] Since the inflation time of a parachute is very short, usually less than 1 second, the gliding distance of the parachute during the inflation process is not large relative to the effective detection area, and meteorological sounding rockets are usually more concerned with the horizontal distance between the parachute opening point and the target point. Therefore, in order to simplify the calculation, the inflation process of the parachute is ignored, and the maximum parachute opening height is estimated using the minimum parachute opening dynamic pressure. Dynamic pressure formula Where P is the dynamic pressure, V is the load flight speed, ρ is the atmospheric density, and the distribution of ρ with height H can be obtained from the reference atmosphere, expressed as: ρ = Atmos (H); the function expression of dynamic pressure P and height H is:

[0096]

[0097] The embodiment of the present invention establishes the relationship between parachute dynamic pressure and altitude, and uses the parachute opening dynamic pressure to calculate the parachute opening altitude.

[0098] Step 2: preset the initial launch point, initial launch angle and maximum parachute opening position of the meteorological sounding rocket based on the initial parachute opening point.

[0099] The above-mentioned step 2 of the embodiment of the present invention includes: setting initial values ​​for the launch point and launch angle of the meteorological sounding rocket based on the detection target point of step 1, and determining the separation point position and speed of the meteorological sounding rocket climbing in the initial state based on the initial values.

[0100] The preset of the maximum parachute opening position in the above step 2 of the embodiment of the present invention includes: determining the minimum parachute opening dynamic pressure of the meteorological sounding rocket based on the function expression of the parachute dynamic pressure P and the height H, and presetting the maximum parachute opening position based on the principle of meeting the height of the minimum parachute opening dynamic pressure.

[0101] The minimum parachute opening dynamic pressure P of the parachute of the embodiment of the present invention min It is known that by substituting the function expression of dynamic pressure P and height H, the minimum dynamic pressure P that satisfies the parachute opening can be obtained. min The height is the maximum parachute opening height, expressed as H ks .

[0102] In the embodiment of the present invention, the actual parachute opening and inflation process is very complicated and difficult to describe objectively and accurately. The minimum parachute opening dynamic pressure is used as the parachute opening judgment condition to calculate the maximum parachute opening height. From the perspective of engineering practice, the amount of calculation is greatly reduced while meeting the accuracy requirements.

[0103] The embodiment of the present invention also calculates the horizontal distance between the maximum parachute opening height point and the launch point to obtain the parachute opening point position. dd Fall to the maximum parachute opening height H ks The falling time at is: The time taken by the load from the separation point to the parachute opening point is t1+t2, the flight in the horizontal direction is uniform motion, and the flight distance in the horizontal direction is Vxy (t1+t2), that is, the horizontal distance between the parachute opening point and the separation point is: L1+L2=V xy (t1+t2); where L1 is the horizontal distance from the separation point to the vertex; L2 is the horizontal distance from the vertex to the parachute opening point; V xy is the horizontal speed of the load after separation; t1 is the time when the load separates to the vertex; t2 is the time when the load falls from the dynamic vertex to the maximum parachute height. The horizontal distance L between the separation point and the launch point fl It can be obtained from the flight trajectory calculation software, so the horizontal distance between the parachute opening point and the launch point is L1+L2+L fl .

[0104] The embodiment of the present invention can solve the flight distance from load separation to parachute opening by using a simple motion equation, thereby obtaining the relative position of the parachute opening point and the launch point. When the parachute is opened quickly at the parachute opening point, the sonde can be effectively detected by quickly decelerating to a range within which the sensor measurement error can be corrected, that is, the position of the parachute opening point is approximately the starting point of the actual effective detection of the sonde.

[0105] Step 3: Input the initial launch point, initial launch angle and maximum parachute opening position into the iteration unit, and the iteration unit continuously iterates and outputs the estimated parachute opening point.

[0106] The above-mentioned step three of the embodiment of the present invention includes: inputting the initial launch point, initial launch angle and maximum parachute opening position determined in step two into the iteration unit of the detection task planning system; the iteration unit adjusts the position and launch angle of the launch point, and changes the position and speed of the separation point based on the position and launch angle of the launch point; the iteration unit continuously iterates and adjusts the position and launch angle of the launch point until the parachute opening point is close to the detection target point, and outputs the estimated parachute opening point.

[0107] When planning the detection mission, the embodiment of the present invention aims to make the parachute opening point as close as possible to the specified detection target point. The result of the planning is to determine the launch point position and the launch angle. The process of task planning is the opposite of the process of calculating the parachute opening point. First, the detection target point is set as the parachute opening point; initial values ​​are set for the launch point and the launch angle, and the separation point position and speed are calculated in the initial state; the final position of the parachute opening point is related to the separation point position and speed. Adjusting the launch point position and the launch angle can change the separation point position and speed. The iteration is adjusted continuously until the calculated parachute opening point position is close to the detection target point, and the preliminary planning of the launch point position and the launch angle is completed.

[0108] After determining the launch point and launch angle, the rocket's flight trajectory can be determined. The final parachute opening point should be close to the detection target point. In this way, after the parachute opens, it can slowly descend with the sonde to detect the atmospheric parameters of the area.

[0109] Step 4: Determine the planned launch point and planned launch angle for launching the meteorological sounding rocket based on the estimated parachute opening point.

[0110] The above-mentioned step 4 of the embodiment of the present invention includes: based on the estimated parachute opening point determined in step 3, determining the launch point position and the launch point angle in the state of the estimated parachute opening point in step 3 as the planned launch point and the planned launch angle.

[0111] Step 5: Determine the rocket flight trajectory based on the planned launch point and the planned launch angle, and determine the parachute opening point based on the rocket flight trajectory.

[0112] The above-mentioned step five of the embodiment of the present invention includes: determining the flight trajectory of the meteorological sounding rocket according to the planned launch point and the planned launch angle determined in step four; the meteorological sounding rocket flies along the flight trajectory, and the final parachute opening point is close to the detection target point, so that the parachute slowly falls with the sonde after opening to detect atmospheric parameters.

[0113] In the embodiment of the present invention, the parachute is quickly opened at the parachute opening point, and the sonde is quickly decelerated to a range within which the sensor measurement error can be corrected, so that effective detection can be performed, that is, the position of the parachute opening point is approximately the starting point of the actual effective detection of the sonde.

[0114] The embodiment of the present invention ignores the atmospheric drag effect before parachute opening, simplifies the flight process from load separation to parachute opening stage into inertial motion under gravity, avoids complex load attitude analysis and atmospheric drag calculation which have little practical impact; ignores the detailed process of parachute inflation, simplifies the parachute opening process into instantaneous action, and the error is acceptable relative to the range of atmospheric detection. The workload of flight trajectory design and detection mission planning is greatly reduced, so that personnel without professional knowledge of aerodynamics can also complete it, which is very meaningful for front-line operators.

[0115] 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 estimating the position of a parachute opening point of a meteorological sounding rocket parachute, characterized in that: include: Step 1: setting the detection target point of the meteorological sounding rocket as the initial parachute opening point; Step 2: presetting the initial launch point, initial launch angle and maximum parachute opening position of the meteorological sounding rocket based on the initial parachute opening point; Step 3: inputting the initial launch point, the initial launch angle and the maximum parachute opening position into an iteration unit, and the iteration unit continuously iterates to output an estimated parachute opening point; Step 4: determining a planned launch point and a planned launch angle for launching a meteorological sounding rocket based on the estimated parachute opening point; Step 5: Determine the rocket flight trajectory according to the planned launch point and the planned launch angle, and determine the parachute opening point position based on the rocket flight trajectory.

2. A method for estimating the opening point of a meteorological sounding rocket parachute according to claim 1, characterized in that: The step one comprises: Determine the detection target point, allow the meteorological sounding rocket to enter the expected detection target area, and the parachute's falling speed is within the speed allowed by the sensor carried by the meteorological sounding rocket; Based on the detected target point, determining the separation point of the meteorological sounding rocket and the rocket body recovery capsule; Determine the trajectory vertex of the meteorological sounding rocket's climbing process according to the separation point; The initial parachute opening point of the meteorological sounding rocket during its descent from the apex of the trajectory is determined.

3. A method for estimating the position of a parachute opening point of a meteorological sounding rocket according to claim 2, characterized in that: The process of determining the separation point includes: (1) After the main engine that propels the meteorological sounding rocket to ascent is shut down, determine the maximum speed of the meteorological sounding rocket as it continues to ascend along the planned trajectory; (2) determining a separation point at which the meteorological sounding rocket separates from the meteorological sounding payload based on the maximum speed during the continued ascending flight; wherein the meteorological sounding payload includes a sonde and a parachute; The process of determining the trajectory vertex includes: (1) Determine the horizontal flight speed V0 of the meteorological sounding rocket xy , vertical flight speed V0 z and the flight angle of attack φ, and the relative velocity ΔV at separation; (2) Calculate the horizontal velocity V of the meteorological sounding payload after the separation point xy and vertical velocity V z ,in: The angle γ between the flight speed direction of the meteorological sounding payload and the horizontal plane is: The horizontal velocity V of the meteorological sounding load xy =V xy =V0 xy +ΔVcos(φ+γ); The vertical velocity V of the meteorological sounding load z =V z =V0 z +ΔVsin(φ+γ).

4. A method for estimating the opening point of a meteorological sounding rocket parachute according to claim 2, characterized in that: The process of determining the initial parachute opening point includes: (1) Determine that the meteorological sounding payload moves inertially under the action of gravity after the separation point, and continues to move horizontally according to V xy Uniform motion, subject to the force of gravity in the vertical direction; (2) Determine the time t1 of the meteorological sounding load rising from the separation point to the top as: Wherein, g represents the acceleration of gravity; the height H of the meteorological sounding load from the separation point to the top dd for: Among them, H fl represents the height of the separation point, ΔH1 represents the climbing height; (3) Establish the function of the flight speed V and the height H of the meteorological sounding payload during its descent from the vertex under the action of gravity Obtain the relationship between flight speed, flight time and altitude during descent from the apex; (4) Establish a function of parachute opening dynamic pressure and altitude, and determine the parachute opening altitude based on the parachute opening dynamic pressure.

5. A method for estimating the position of a parachute opening point of a meteorological sounding rocket according to claim 4, characterized in that: In the function of establishing the dynamic pressure and height of the parachute, the function expression of the dynamic pressure P and the height H of the parachute is: Among them, V represents the parachute flight speed, Atmos (H) represents the atmospheric density; The minimum parachute opening dynamic pressure is determined, and the height that satisfies the minimum parachute opening dynamic pressure is determined as the maximum parachute opening height.

6. A method for estimating the opening point of a meteorological sounding rocket parachute according to claim 1, characterized in that: The second step comprises: Based on the detection target point in step one, initial values ​​are set for the launch point and launch angle of the meteorological sounding rocket, and based on the initial values, the separation point position and speed of the meteorological sounding rocket climbing in the initial state are determined.

7. A method for estimating the position of a parachute opening point of a meteorological sounding rocket according to claim 6, characterized in that: The preset maximum parachute opening position in step 2 includes: The minimum parachute opening dynamic pressure of the meteorological sounding rocket is determined based on the function expression of the parachute dynamic pressure P and the height H, and the maximum parachute opening position is preset based on the height that meets the minimum parachute opening dynamic pressure.

8. A method for estimating the position of a parachute opening point of a meteorological sounding rocket according to claim 1, characterized in that: The step three comprises: Inputting the initial launch point, the initial launch angle and the maximum parachute opening position determined in step 2 into an iteration unit of a detection mission planning system; The iteration unit adjusts the position and the launch angle of the launch point, and changes the position and the speed of the separation point based on the position and the launch angle of the launch point; The iterative unit continuously iteratively adjusts the position and the launch angle of the launch point until the parachute opening point is close to the detection target point, and outputs the estimated parachute opening point.

9. A method for estimating the position of a parachute opening point of a meteorological sounding rocket according to claim 1, characterized in that: The fourth step comprises: Based on the estimated parachute opening point determined in step 3, the launch point position and the launch point angle in the state of the estimated parachute opening point in step 3 are determined as the planned launch point and the planned launch angle.

10. A method for estimating the position of a parachute opening point of a meteorological sounding rocket according to claim 1, characterized in that: The step five comprises: Determine the flight trajectory of the meteorological sounding rocket according to the planned launch point and the planned launch angle determined in step 4; The meteorological sounding rocket flies along the flight trajectory, and the final parachute opening point is close to the detection target point, so that after the parachute opens, it slowly descends with the sonde to detect atmospheric parameters.

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