Error compensation method for near space air pressure in-situ detection

Abstract

The invention provides an error compensation method for near space air pressure in-situ detection, and belongs to the technical field of near space environment detection, and the method comprises the steps: determining a change curve of the speed along with the height in the falling process of a sounding assembly; modeling an external flow field of the sounding assembly, and analyzing an external airflow field and a heat flow field of the sounding assembly; constructing an air pressure sensor arrangement point position temperature conversion model; constructing an error calculation model of the barometric sensor based on the position of the barometric sensor in the internal flow field, the analysis result and the heat flow field model; acquiring air pressure measurement data and environment measurement data of the near space; and according to the environmental parameter in-situ measurement data, compensating the near space in-situ air pressure measurement data by using the error calculation model to obtain a near space air pressure measurement error. The problem that the high-speed falling type sounding assembly cannot measure the ambient air pressure accurately is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of near-space environment detection, and in particular relates to an error compensation method for in-situ detection of near-space air pressure. Background Art

[0002] High-precision detection of near-space atmospheric environment is of great significance to the design of near-space aircraft, and further to the competition for near-space strategic areas. The air-based detection system can place the detection payload directly in the LJKJ environment to achieve high-precision in-situ detection, which can meet the needs of meteorological parameter detection in the LJKJ environment.

[0003] At present, there are two mainstream ways of in-situ detection of near-space. One way is to use a sounding balloon to carry a sounding component to detect near-space. The detection range of this method is mainly concentrated in the near-space environment within 30km. The other way is to use a sounding rocket to carry a sounding component, bring the sounding component to the near-space environment, and then drop and scatter it, and conduct environmental detection during the descent. The detection range of the second method can cover the entire near-space altitude at most, depending on the capability of the sounding rocket. During the descent of the sounding component, due to the fast descent speed, the relative airflow during the descent of the sounding component, and the aerodynamic heat generated by the friction between the surface of the sounding component and the air, the pressure sensor inside the sounding component will cause detection errors.

[0004] At present, piezoresistive pressure sensors, Pirani pressure sensors or resonant pressure sensors are often used for in-situ measurement of near-space air pressure. Piezoresistive pressure sensors have a small range, their accuracy is greatly affected by temperature, and their long-term stability is poor; although Pirani pressure sensors are suitable for vacuum system monitoring, they have a slow response speed and high power consumption; resonant pressure sensors have extremely high accuracy and stability, strong anti-interference ability, and can achieve digital output, which is easy to integrate into modern electronic systems, and is especially suitable for high-precision air pressure measurement and long-term monitoring. However, resonant pressure sensors are sensitive to temperature changes, and external stress also causes certain measurement errors to resonant sensors.

[0005] At present, in-situ air pressure detection in near-space mainly uses sounding balloons carrying sounding components for in-situ detection. The use of sounding rockets for downward detection can effectively increase the measurement altitude range of in-situ air pressure detection.

[0006] The in-situ detection of near-space air pressure involves many interference factors, including aerodynamic heat and pressure changes caused by high-speed airflow. Currently, most in-situ measurements of near-space air pressure only consider the pressure changes caused by high-speed airflow, and lack a comprehensive analysis of the interference factors, resulting in large errors in near-space air pressure measurements. Summary of the invention

[0007] In view of the above-mentioned deficiencies in the prior art, the present invention provides an error compensation method for in-situ detection of near-space air pressure. Based on the theory of aerodynamics and thermodynamics, the present invention obtains an error compensation model of the air pressure sensor in the sounding assembly through simulation analysis of the airflow field inside the sounding assembly, adopts a near-air airship platform or a near-air rocket platform to launch the sounding assembly, collects air pressure data in near-space, synchronously collects atmospheric environment parameter data, and compensates the actual measurement data of the air pressure sensor according to the error compensation model.

[0008] In order to achieve the above purpose, the technical solution adopted by the present invention is: an error compensation method for in-situ detection of near-space air pressure, comprising the following steps:

[0009] S1. Determine the curve of velocity variation with height during the falling process of the sounding assembly;

[0010] S2, modeling the external flow field of the sounding assembly;

[0011] S3, constructing a temperature conversion model for the arrangement points of the air pressure sensors;

[0012] S4, constructing an error calculation model of the air pressure sensor based on the position of the air pressure sensor in the internal flow field, the modeling results of S2 and the thermal flow field model;

[0013] S5. Obtaining air pressure measurement data and environmental measurement data of the near space;

[0014] S6. Based on the in-situ measurement data of the environmental parameters, the error calculation model is used to compensate the in-situ air pressure measurement data of the near space, so as to obtain the near space air pressure measurement error and complete the error compensation for the in-situ detection of the near space air pressure.

[0015] Furthermore, the S1 is specifically:

[0016] According to the expected initial falling height and initial velocity of the sounding assembly, a dynamic analysis is performed to obtain the velocity variation curve of the sounding assembly during its falling process.

[0017] Furthermore, the S2 is specifically:

[0018] The external flow field of the sounding component is modeled, and the external airflow field and thermal flow field of the sounding component are analyzed to obtain the gas flow rate, temperature and air pressure at the air flow hole position where the internal pressure of the sounding component is exchanged with the external pressure.

[0019] Furthermore, the expression of the temperature conversion model of the pressure sensor arrangement point in S3 is as follows:

[0020]

[0021] Among them, TP Indicates the absolute temperature of the pressure sensor placement point, T 1 and T 2 Respectively represent the windward tip temperature sensor data and the side wall temperature sensor data, ω 1 and ω 2 Both represent weight coefficients.

[0022] Furthermore, the expression of the error calculation model of the air pressure sensor in S4 is as follows:

[0023]

[0024] Where q represents the pressure measurement error, P 1 Indicates the air pressure value directly obtained by the air pressure sensor, R represents the gas constant, T P represents the absolute temperature of the gas, v represents the relative speed between the sounding assembly and the airflow, ω v It represents the conversion weight between the relative speed between the sonde assembly and the airflow and the airflow velocity at the pressure sensor arrangement point.

[0025] Furthermore, the expression of the near-space air pressure measurement error in S6 is as follows:

[0026] P=P 1 -q

[0027] Where P represents the near-space pressure measurement error, P 1 It represents the air pressure value directly obtained by the air pressure sensor, and q represents the air pressure measurement error.

[0028] Beneficial effects of the present invention:

[0029] (1) The error compensation method for in-situ detection of near-space air pressure of the present invention uses various types of airborne platforms such as sounding rockets, airborne airships, and sounding balloons to carry sounding components for in-situ detection of near-space air pressure. It has the advantages of maneuverable control, strong carrying capacity, high detection altitude, and medium floating time, and expands the detection range of near-space air pressure parameters.

[0030] (2) The error compensation method for in-situ detection of near-space air pressure of the present invention adopts an air pressure sensor (resonant air pressure sensor) with the advantages of good linearity, high measurement accuracy and large range, thereby expanding the detection range of near-space air pressure parameters.

[0031] (3) The present invention provides an error compensation method for in-situ detection of near-space air pressure. By simulating and analyzing the effects of aerodynamic heat and air flow field during the falling process of the sounding assembly, an error compensation model of the resonant air pressure sensor is obtained to reduce the effect of the high-speed falling of the sounding assembly on the measured air pressure of the air pressure sensor.

[0032] (4) The present invention provides an error compensation method for in-situ detection of near-space air pressure. The sensor carried by the sounding assembly collects temperature, air velocity, and altitude in-situ as input parameters of the error compensation model, thereby achieving error compensation for in-situ near-space air pressure measurement and obtaining a near-space air pressure value that is closer to the actual value. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A flow chart of an error compensation method for in-situ detection of near-space air pressure is shown.

[0034] Figure 2 The curve of the falling speed of the sounding assembly of the embodiment changing with the height is shown.

[0035] Figure 3 The external flow field model of the sounding assembly of the embodiment is shown.

[0036] Figure 4 A schematic diagram of the internal isotherms of the sounding assembly of the embodiment is shown.

[0037] Figure 5 A schematic diagram of the internal flow field of the sounding assembly and the arrangement points of the air pressure sensors of the embodiment are shown.

[0038] Among them, 1-sonde assembly, 2-external flow field, 3-positioning points of air pressure sensors. DETAILED DESCRIPTION

[0039] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0040] Example

[0041] like Figure 1 As shown, the present invention provides an error compensation method for in-situ detection of near-space air pressure, and its implementation method is as follows:

[0042] S1. Determine the curve of the velocity of the sounding assembly changing with height during its descent, which is specifically:

[0043] According to the expected initial falling height and initial velocity of the sounding assembly, a dynamic analysis is performed to obtain the velocity-height variation curve of the sounding assembly during its falling process.

[0044] S2. Model the external flow field of the sounding assembly, which is as follows:

[0045] Model the external flow field of the sounding assembly, analyze the external airflow field and thermal flow field of the sounding assembly, and obtain the gas flow rate, temperature and air pressure at the air flow hole position where the pressure inside the sounding assembly is exchanged with the external pressure;

[0046] S3, constructing a temperature conversion model for the arrangement points of the air pressure sensors;

[0047] S4, constructing an error calculation model of the air pressure sensor based on the position of the air pressure sensor in the internal flow field, the modeling results of S2 and the thermal flow field model;

[0048] S5. Obtaining air pressure measurement data and environmental measurement data of the near space;

[0049] S6. Based on the in-situ measurement data of the environmental parameters, the error calculation model is used to compensate the in-situ air pressure measurement data of the near space, so as to obtain the near space air pressure measurement error and complete the error compensation for the in-situ detection of the near space air pressure.

[0050] In this embodiment, the present invention optimizes the layout positions of the near-space temperature sensor, the air pressure sensor, the inertial navigation system, and the Beidou navigation module, thereby reducing the error caused by the sensor hardware layout.

[0051] In this embodiment, the velocity curve of the sounding assembly falling process with the height is determined, such as Figure 2 As shown, using dynamic theory, according to the expected initial falling height and initial velocity of the sounding assembly, a curve of the falling velocity of the sounding assembly changing with the falling height is obtained. In the embodiment, the initial falling velocity is 550m / s and the initial falling height is 72km for dynamic analysis.

[0052] In this embodiment, the external flow field of the sounding assembly is modeled. Preferably, the center position of the windward surface of the sounding assembly and the arrangement point of the temperature sensor in the adjacent space during the falling process of the sounding assembly are used as the airflow holes for exchanging the pressure inside the sounding assembly with the external environment. The Ansys Fluent software is used to analyze the external airflow field and thermal flow field of the sounding assembly to obtain the gas flow rate, temperature and air pressure at the airflow hole position on the wall of the sounding assembly. In the embodiment, the height change interval is 0.5 km, and the setting of the ambient air pressure and temperature is based on the coesa76 model, such as Figure 3 shown.

[0053] In this embodiment, the temperature of the pressure sensor arrangement point is determined, such as Figure 4As shown, preferably, Ansys Fluent is used to perform aerodynamic and thermodynamic analysis on the interior of the sounding assembly at different heights, the temperature sensor arrangement point at the tip of the windward surface of the sounding assembly is selected as the pressure inlet, the temperature sensor arrangement point on the side wall of the sounding assembly is selected as the pressure outlet, the temperature is set to the temperature calculation result of the corresponding point at the corresponding height in step S2, the result of each height interval is analyzed for internal isotherms, and a conversion model of the temperature of the pressure sensor arrangement point and the temperature of the points where the two temperature sensors are located is obtained;

[0054] The temperature conversion model of the pressure sensor layout points is shown below:

[0055]

[0056] Among them, T P Indicates the absolute temperature of the pressure sensor placement point, T 1 and T 2 Respectively represent the windward tip temperature sensor data and the side wall temperature sensor data, ω 1 and ω 2 Both represent weight coefficients.

[0057] In this embodiment, the error calculation model of the air pressure sensor is determined, such as Figure 5 As shown, according to the simulation result of step S2, the arrangement point of the temperature sensor at the tip of the windward surface of the sounding assembly is selected as the pressure inlet, and the arrangement point of the temperature sensor on the side wall of the sounding assembly is selected as the pressure outlet. Ansys Fluent is used to perform aerodynamics at different heights inside the sounding assembly, and the pressure is set to the pressure and temperature calculation results of the corresponding point at the corresponding height in step S2. The results of each height interval are analyzed for internal streamlines to obtain the conversion model of the dynamic pressure at the point where the pressure sensor is located and the conversion model of the temperature at the point where the pressure sensor is arranged and the temperature at the points where the two temperature sensors are located.

[0058] The calculation model of the pressure error at the point where the pressure sensor is located is shown in the following formula:

[0059]

[0060] Where q represents the pressure error, P 1 It represents the air pressure value directly obtained by the air pressure sensor, R represents the gas constant, for air R = 287, v represents the relative speed between the sounding assembly and the airflow, ω v It represents the conversion weight between the relative speed between the sonde assembly and the airflow and the airflow velocity at the pressure sensor arrangement point.

[0061] In this embodiment, the air pressure measurement data and environmental measurement data of the near space are obtained, the surface temperature is measured by using the temperature sensor carried by the sounding assembly, and the relative airflow velocity is measured by using the inertial navigation and Beidou navigation modules;

[0062] This implementation is named to compensate the measured value. The actual measured value of the air pressure in the adjacent space is shown in the following formula:

[0063] P=P 1 -q

[0064] Where P represents the near-space pressure measurement error, P 1 It represents the air pressure value directly obtained by the air pressure sensor, and q represents the air pressure measurement error.

[0065] Through simulation results, the aerodynamic heat and pressure changes generated during the falling process of the sounding assembly will cause obvious errors to the sounding assembly. After the error compensation of the present invention, the near-space air pressure in-situ measurement data can be processed more effectively to obtain high-precision air pressure measurement values. That is, according to the obtained near-space air pressure measurement error, the reliability is greatly enhanced compared to before the air pressure error correction. The air pressure value after error correction is used as the final high-precision value, which can be applied to the subsequent construction of the near-space environment air pressure model to solve engineering problems related to the near-space air pressure.

[0066] The specific description above further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for error compensation of near-space air pressure in-situ detection, characterized in that: The following steps are involved: S1. Determine the curve of velocity variation with height during the falling process of the sounding assembly; S2. Modeling the external flow field of the sounding assembly, analyzing the external airflow field and thermal flow field of the sounding assembly, wherein when modeling the external flow field of the sounding assembly, the velocity in the variation curve is used as a simulation input parameter for external flow field modeling; S3, constructing a temperature conversion model for the arrangement points of the air pressure sensors; S4, constructing an error calculation model of the pressure sensor based on the temperature conversion model of the pressure sensor arrangement points and the analysis results of S2; S5. Obtaining in-situ air pressure measurement data and environmental parameter in-situ measurement data of the near space; S6. Based on the in-situ measurement data of the environmental parameters, the error calculation model is used to compensate the in-situ air pressure measurement data of the near space, so as to obtain the near space air pressure measurement error and complete the error compensation of the in-situ detection of the near space air pressure.

2. The error compensation method for in-situ detection of near-space air pressure according to claim 1, characterized in that: The S1 is specifically: According to the expected initial falling height and initial velocity of the sounding assembly, a dynamic analysis is performed to obtain the velocity variation curve of the sounding assembly during its falling process.

3. The error compensation method for in-situ detection of near-space air pressure according to claim 1, characterized in that: The S2 is specifically: The external flow field of the sounding component is modeled, and the external airflow field and thermal flow field of the sounding component are analyzed to obtain the gas flow rate, temperature and air pressure at the air flow hole position where the internal pressure of the sounding component is exchanged with the external pressure.

4. The error compensation method for in-situ detection of near-space air pressure according to claim 1, characterized in that: The expression of the temperature conversion model of the pressure sensor arrangement point in S3 is as follows: Among them, T P represents the absolute temperature of the pressure sensor arrangement point, T1 and T2 represent the windward tip temperature sensor data and the side wall temperature sensor data respectively, and ω1 and ω2 represent weight coefficients.

5. The error compensation method for in-situ detection of near-space air pressure according to claim 1, characterized in that: The expression of the error calculation model of the air pressure sensor in S4 is as follows: Where q represents the pressure measurement error, P1 represents the pressure value directly obtained by the pressure sensor, R represents the gas constant, and T P represents the absolute temperature of the gas, v represents the relative speed between the sounding assembly and the airflow, ω v It represents the conversion weight between the relative speed between the sonde assembly and the airflow and the airflow velocity at the pressure sensor arrangement point.

6. The error compensation method for in-situ detection of near-space air pressure according to claim 1, characterized in that: The expression of the near-space air pressure measurement error in S6 is as follows: P=P1-q Among them, P represents the near-space air pressure measurement error, P1 represents the air pressure value directly obtained by the air pressure sensor, and q represents the air pressure measurement error.

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