A method and device for constructing a wide-area environmental optical turbulence probability prediction model

Abstract

The application discloses a kind of methods and devices for constructing wide-area environmental optical turbulence probability prediction model, the method includes S1, obtains ball-borne turbulence detection historical experimental data, obtains meteorological parameter profile and atmospheric optical turbulence profile;S2, the product of meteorological parameter gradient quantity is calculated according to the meteorological parameter profile corresponding to historical experimental data;S3, the model coefficient profile is calculated using the product of atmospheric optical turbulence profile and meteorological parameter gradient quantity, and the model coefficient profile library of atmospheric optical turbulence of typical region is calculated and obtained accordingly;S4, optical turbulence model coefficient probability density distribution is calculated according to the model coefficient profile library of atmospheric optical turbulence of typical region;S5, optical turbulence probability prediction model is constructed according to optical turbulence model coefficient probability density distribution.The application makes up the limitation of existing optical turbulence detection technology and mode and the problem that optical turbulence empirical mode (average mode) based on limited turbulence detection test data is not applicable in many application scenarios.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of atmospheric optical parameter detection, and in particular to a method for constructing a wide-area environmental optical turbulence probability prediction model, a prediction method and device. BACKGROUND

[0002] At present, most advanced photoelectric systems are used in the atmosphere, and the system performance will inevitably be affected by the atmosphere. The degradation effect of atmospheric optical turbulence on beam quality limits the effective distance and effect of advanced photoelectric systems, and becomes the bottleneck of ground-based photoelectric engineering application.

[0003] With the gradual deployment and wide range of trial use of photoelectric systems, the uncertainty influence of atmospheric optical turbulence intensity and its spatio-temporal variation characteristics in wide-area environment on photoelectric systems has become a dilemma faced by users.

[0004] The spatial distribution of atmospheric optical turbulence is usually measured by using sounding balloons, aircraft, radar and other methods, but the traditional atmospheric optical turbulence detection method and technology have defects such as poor real-time performance, insufficient spatial representativeness, and low cost-effectiveness when obtaining the optical turbulence characteristics in wide-area environment, and there is an urgent need to construct a model tool for evaluating the atmospheric optical turbulence characteristics and its influence on system performance when serving the wide-area environment use of photoelectric systems. SUMMARY

[0005] The purpose of the present application is to provide a method for constructing a wide-area environmental atmospheric optical turbulence probability prediction model to realize the prediction and characterization of wide-area environmental atmospheric optical turbulence probability.

[0006] To this end, the present application provides a method for constructing a wide-area environmental optical turbulence probability prediction model, comprising: S1, obtaining historical experimental data of ball-borne turbulence detection to obtain meteorological parameter profiles (P(h), T(h), u(h), v(h) and θ(h)) and atmospheric optical turbulence profiles S2, calculating the product M(h) of the meteorological parameter gradient quantity according to the meteorological parameter profile corresponding to the historical experimental data; S3, calculating the model coefficient profile k(h) by using the product M(h) of the atmospheric optical turbulence profile and the meteorological parameter gradient quantity, and obtaining the model coefficient profile library of atmospheric optical turbulence in typical areas: k(h)1, k(h)2, k(h)3, …, k(h) N ; S4, according to the model coefficient profile library of atmospheric optical turbulence in typical areas: k(h)1, k(h)2, k(h)3, …, k(h) N , the optical turbulence model coefficient probability density distribution k(h) p is sequentially calculated from the ground to the high altitude point data at the same altitude, wherein the subscript p is the probability value; and S5, according to the optical turbulence model coefficient probability density distribution k(h)p constructing an optical turbulence probability prediction model: wherein is the predicted optical turbulence profile probability distribution.

[0007] According to another aspect of the present application, there is provided a wide-area environmental optical turbulence profile probability distribution prediction method, comprising the following steps: S11, obtaining a wide-area environmental optical turbulence probability prediction model, wherein the optical turbulence probability prediction model is obtained according to the method for constructing a wide-area environmental optical turbulence probability prediction model described above; S12, obtaining the meteorological parameter profile (P(h), T(h), u(h), v(h) and θ(h)) corresponding to the atmospheric optical turbulence to be predicted, and calculating the product M(h) of the meteorological parameter gradient quantity according to the meteorological parameter profile; S13, inputting the specified optical turbulence model coefficient probability density distribution and the calculated product M(h) of the meteorological parameter gradient quantity into the optical turbulence prediction model, and outputting the predicted optical turbulence profile probability distribution.

[0008] The present application also provides a wide-area environmental optical turbulence probability prediction device, comprising a computer program, which, when executed, is used to implement each step of the wide-area environmental optical turbulence profile probability distribution prediction method described above.

[0009] The present application is around the prediction demand of the wide-area environmental atmospheric optical turbulence spatiotemporal distribution characteristics for the deployment and application of advanced optoelectronic systems, proposes a wide-area environmental atmospheric optical turbulence probability prediction model based on atmospheric environmental parameters and atmospheric turbulence physical laws, forms a wide-area environmental optical turbulence spatiotemporal distribution probability prediction technology, provides an effective technical means for obtaining the atmospheric optical turbulence spatiotemporal distribution characteristics in a wide-area environment, and effectively improves the support capability of the atmospheric optical turbulence characteristic parameters in optoelectronic engineering applications.

[0010] The wide-area environmental optical turbulence spatiotemporal distribution probability prediction characterization technology formed based on the present application can effectively make up for the limitations of the existing optical turbulence detection technologies and methods and the problem that the optical turbulence empirical model (average model) constructed based on limited turbulence detection test data is not applicable in many application scenarios, and has important engineering application prospects.

[0011] In addition to the objects, features and advantages described above, the present application has other objects, features and advantages. The present application will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0012] The drawings accompanying the specification of the present application form a part thereof, serve to provide further understanding of the present application, and together with the description of the present application, serve to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0013] Figure 1is a schematic diagram of a turbulent sounding measurement device;

[0014] Figure 2 is a schematic diagram of an optical turbulence measurement module;

[0015] Figure 3 is a flow chart of the construction of the coefficients of the mathematical model of atmospheric optical turbulence;

[0016] Figure 4 is a flow chart of the calculation of the probability distribution of the coefficients of the model of atmospheric optical turbulence;

[0017] Figure 5 is a flow chart of the probability prediction of wide-area environmental atmospheric optical turbulence. DETAILED DESCRIPTION

[0018] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0019] The present application is based on previous research on atmospheric optical turbulence detection and model construction, driven by abundant field observation data, based on atmospheric physical laws, and using mathematical statistics and big data analysis techniques as a means to construct a wide-area environmental atmospheric optical turbulence probability prediction model and form a wide-area environmental optical turbulence spatiotemporal distribution probability prediction technology.

[0020] (1) Optical turbulence detection test and data storage

[0021] The present application uses a high-altitude turbulence meteorological detection system developed by the Hefei Institute of Material Science / Anhui Institute of Optics and Precision Mechanics of the Chinese Academy of Sciences.

[0022] The high-altitude turbulence meteorological detection system is composed of a sounding balloon 20, a measurement system 10 carried by the sounding balloon 20, a ground receiving system 30, and a big data intelligent statistical learning system 40, as shown in Figure 1 .

[0023] The high-altitude turbulence meteorological detection system can measure the vertical profiles of atmospheric optical turbulence and the vertical profiles of five conventional meteorological elements, namely air temperature, humidity, air pressure, wind speed, and wind direction.

[0024] Atmospheric optical turbulence is detected by an optical turbulence measurement module, and the detection of temperature, air pressure, and humidity is completed by a conventional meteorological parameter measurement module, such as a temperature, pressure, and humidity sensor measurement board. The ground receiving system 30, composed of a receiving antenna and a receiving mechanism, can receive the original high-resolution vertical profile data of conventional meteorological parameters and atmospheric optical turbulence and other parameters transmitted by the measurement system 10.

[0025] A single sounding measurement can obtain temperature, humidity, wind speed, wind direction, and atmospheric optical turbulence High-resolution vertical profiles of equal parameters.

[0026] The detection system uses Beidou positioning method to measure wind, uses the Beidou receiver installed on the sounding balloon to determine the longitude, latitude and height of the position of the balloon, and obtains the wind speed and direction in the air through calculation.

[0027] For visible light and near-infrared band, the fluctuation of atmospheric refractive index is mainly caused by temperature change. According to the local homogeneous isotropic turbulence theory, the atmospheric temperature structure constant The temperature difference square average of the distance r between two points in space is usually measured by a pair of micro-temperature probes on the micro-temperature sensor.

[0028] The temperature structure constant Can be expressed as:

[0029]

[0030] In the formula, And The position vector is represented, the unit is m, T is the temperature, the unit is K, < > represents the ensemble average. L0 and l0 represent the outer scale and the inner scale of turbulence, respectively, and the unit is m. The atmospheric optical turbulence The temperature structure constant Can be expressed as:

[0031]

[0032] Wherein, the unit of air pressure P is hPa, the atmospheric refractive index structure constant The unit of m -2 / 3 .

[0033] The structure of the optical turbulence measurement module is shown in Figure 2 It is composed of a rod 11, two micro-temperature probes 12 and 13 arranged at a certain distance apart at both ends of the rod, and a data acquisition and processing unit 14 placed in the middle of the rod.

[0034] Two micro-temperature probes at a certain distance (usually 1m) will sense the change of environmental temperature at two points in space as a change of resistance value, and convert it to a change of voltage through an unbalanced bridge. The voltage change ΔV output from the voltage amplifier corresponds to a certain temperature change ΔT, and A is the calibration coefficient.

[0035] ΔV=A·ΔT ------------------------------------ (3)

[0036] From formula (1) and formula (3), the square average of the temperature difference between two points in space is obtained And the atmospheric optical turbulence is obtained from formula (2)

[0037] The present application firstly classifies the historical turbulence detection data into meteorological parameters and atmospheric optical turbulence; secondly, the historical turbulence detection data is cleaned and quality controlled to ensure data reliability. In addition, turbulence sounding measurement tests are carried out in typical areas to effectively increase the amount of data information and form an atmospheric optical parameter data set.

[0038] (2) Constructing an optical turbulence mathematical model

[0039] In the visible light and infrared waveband, the influence of water vapor can be ignored, and according to the local uniformity and isotropy theory of turbulence, the atmospheric optical turbulence intensity can be represented by meteorological parameters:

[0040]

[0041] In the formula, h is the altitude, T is the air temperature, P is the air pressure, θ is the potential temperature, L is the mixing scale, and k is the coefficient. In the prior art, the k coefficient is a constant, and the k coefficient is usually taken as 2.8 at each height point from the ground to an altitude of about 30 km. However, in fact, the spatial distribution of atmospheric turbulence is obviously different from the ground to the high altitude, and if the k value is determined as a constant at different height points, it is obviously not consistent with the spatial difference and variation rule of atmospheric turbulence. The present application improves this, and changes the coefficient profile that changes with the height, and gives the distribution of the coefficient profile under different probabilities.

[0042] According to the atmospheric turbulence vortex law, the turbulence kinetic energy can be parameterized and represented by the wind shear. Thus, the mixing scale L can be represented as:

[0043]

[0044] Combining formula (4) and formula (5), the atmospheric optical turbulence intensity can be represented as:

[0045]

[0046] In the formula, S is the wind shear u and v are the meridional and latitudinal horizontal wind components, and g is the gravitational acceleration.

[0047] The above physical parameterization model is further simplified, and the atmospheric optical turbulence intensity can be represented as:

[0048]

[0049] As can be seen from formula (7), except for the coefficient k, other parameters can be calculated from atmospheric parameters. Let M be the product of the gradients of each meteorological parameter, that is,

[0050]

[0051] Combining formula (7) and formula (8), the atmospheric optical turbulence model coefficient k can be expressed as:

[0052]

[0053] In the formula, the subscript N is the sample number.

[0054] In a turbulence meteorological sounding measurement experiment, meteorological parameter profiles (P(h), T(h), u(h), v(h) and θ(h)) and atmospheric optical turbulence profiles The product M(h) of the meteorological parameter gradient quantity is calculated by formula (8). The atmospheric optical turbulence profile is measured The model coefficient profile k(h) is obtained by combining formula (9). The technical process is shown in the figure. Figure 4 The calculation example of the atmospheric optical turbulence model coefficient k is shown in Table 1.

[0055] Table 1 Construction example of atmospheric optical turbulence model coefficient

[0056]

[0057] (3) Construction of wide-area environmental atmospheric optical turbulence probability prediction model

[0058] According to the atmospheric optical parameter data set formed by a large number of turbulence meteorological sounding measurement experiments in typical regions (Gobi desert, coastal sea, plateau mountain and other typical atmospheric optical environment regions), the atmospheric optical turbulence model coefficient profile k(h) is calculated by mathematical statistical analysis, and a typical region atmospheric optical turbulence model coefficient profile library: k(h)1, k(h)2, k(h)3, …, k(h) N .

[0059] The role of the k coefficient in the turbulence model is equivalent to the weight coefficient. The present application not only gives the change of the weight coefficient with height (i.e. the coefficient profile), but also gives the distribution of the weight coefficient profile under different probabilities according to the statistical law.

[0060] According to the mathematical statistical theory, the normal distribution expression can be expressed as:

[0061]

[0062] In the formula, x is the independent variable, is the average value, and σ is the standard deviation. The variable x is replaced by the atmospheric optical turbulence model coefficient k, and the probability density function of the optical turbulence model coefficient can be expressed. Therefore, the wide-area environmental atmospheric optical turbulence model coefficient profile can be statistically analyzed and processed, and the probability density distribution of the optical turbulence model coefficient profile is calculated.

[0063] Specifically, according to the atmospheric optical turbulence model coefficient profile data, the optical turbulence model coefficient probability density distribution is calculated for the same altitude point data from the ground to the high altitude, and then the probability distribution of the model coefficient at 1%, 15%, 50%, 85%, and 99% can be obtained. The calculation process of the atmospheric optical turbulence model coefficient profile probability distribution is shown in Figure 4 Table 2 shows an example of the calculation of the wide-area environmental optical turbulence model coefficient profile probability distribution.

[0064] Table 2 shows an example of the calculation of the wide-area environmental optical turbulence model coefficient profile probability distribution.

[0065]

[0066] According to the above method, the optical turbulence model coefficient profile probability distribution is calculated, and the wide-area environmental optical turbulence probability prediction model (named: Probabilistic prediction Model for wide-area Optical Turbulence, ProMOT) is obtained by combining equations (7) and (8). The ProMOT model can be expressed as:

[0067]

[0068] In the formula, subscript p is 1%, 15%, 50%, 85%, 99%, etc.

[0069] Based on meteorological sounding data, numerical model data, reanalysis data, and satellite remote sensing data, atmospheric environmental data is extracted to construct an atmospheric meteorological data set containing wind speed, temperature, pressure, and other elements. Combined with the wide-area environmental atmospheric optical turbulence probability prediction model, the wide-area environmental atmospheric optical turbulence probability distribution is predicted, and the wide-area environmental atmospheric optical turbulence profile probability distribution is characterized.

[0070] It should be noted that in the iteration process of the wide-area environmental atmospheric optical turbulence probability model, the model prediction results need to be evaluated continuously using multi-source measured data, and the atmospheric optical turbulence probability prediction model needs to be continuously optimized. The wide-area environmental optical turbulence probability distribution prediction process is shown in Figure 5 .

[0071] The above description is only an embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for constructing a wide-area environmental optical turbulence probability prediction model, characterized in that: include: S1. Obtain historical experimental data of ball-borne turbulence detection and obtain meteorological parameter profiles (P(h), T(h), u(h), v(h) and θ(h)) and atmospheric optical turbulence profiles S2. Calculate the product M(h) of the meteorological parameter gradient according to the meteorological parameter profile corresponding to the historical experimental data; S3. Using atmospheric optical turbulence profiles The product of the gradient of the meteorological parameters M(h) is used to calculate the model coefficient profile k(h), and the atmospheric optical turbulence model coefficient profile library for typical regions is obtained based on this calculation: k(h)1, k(h)2, k(h)3, ..., k(h) N ; S4. Based on the atmospheric optical turbulence model coefficient profile library for typical regions: k(h)1, k(h)2, k(h)3, ..., k(h) N , from the ground to the high altitude, the data of the same altitude point are calculated in sequence to obtain the probability density distribution k(h) of the optical turbulence model coefficients p , subscript p is the probability value; S5. According to the probability density distribution of optical turbulence model coefficients k(h) p Constructing an optical turbulence probability prediction model: in is the probability distribution of the predicted optical turbulence profile.

2. The method for constructing a wide-area environmental optical turbulence probability prediction model according to claim 1, characterized in that: The calculation formula of the product of meteorological parameter gradients M(h) is as follows: Where S(h) is wind shear u and v are the longitudinal and latitudinal horizontal wind components, h is the altitude, T(h) is the air temperature profile, P(h) is the pressure profile, and θ(h) is the potential temperature profile.

3. The method for constructing a wide-area environmental optical turbulence probability prediction model according to claim 1, characterized in that: The atmospheric optical turbulence profile The atmospheric refractive index structure constant Calculation yields: Among them, the atmospheric refractive index structure constant Measured by the optical turbulence measurement module of the sounding.

4. The method for constructing a wide-area environmental optical turbulence probability prediction model according to claim 1, characterized in that: The optical turbulence model coefficient probability density distribution k(h) p Includes: k(h) 1％ 、k(h) 15％ 、k(h) 50％ 、k(h) 85％ 、k(h) 99％ .

5. A method for predicting the probability distribution of optical turbulence profiles in a wide-area environment, characterized in that: The following steps are involved: S11. Obtaining a wide-area environmental optical turbulence probability prediction model, wherein the optical turbulence probability prediction model is obtained according to the method for constructing a wide-area environmental optical turbulence probability prediction model according to any one of claims 1 to 4; S12. Obtain meteorological parameter profiles (P(h), T(h), u(h), v(h), and θ(h)) corresponding to the atmospheric optical turbulence to be predicted, and calculate the product M(h) of the meteorological parameter gradients based on the profiles; S13. Input the product M(h) of the specified optical turbulence model coefficient probability density distribution and the calculated meteorological parameter gradient into the optical turbulence prediction model, and output the predicted optical turbulence profile probability distribution.

6. The method for predicting the probability distribution of optical turbulence profiles in a wide-area environment according to claim 5, characterized in that: The meteorological parameter profiles (P(h), T(h), u(h), v(h) and θ(h)) corresponding to the atmospheric optical turbulence to be predicted are measured data.

7. The method for predicting the probability distribution of optical turbulence profiles in a wide-area environment according to claim 5, characterized in that: The meteorological parameter profiles (P(h), T(h), u(h), v(h) and θ(h)) corresponding to the atmospheric optical turbulence to be predicted are meteorological forecast data.

8. A device for predicting the probability of optical turbulence in a wide-area environment, comprising a computer program, characterized in that: When executed, the program is used to implement each step of the method for predicting the probability distribution of optical turbulence profiles in a wide-area environment according to claim 5.

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