KR102677764B1 - Atmospheric refraction positioning error correction method for optical remote sensing satellite image in qinghai-tibet plateau region - Google Patents

Abstract

The present invention relates to satellite remote sensing technology, and the purpose of the present invention is to provide a method for correcting atmospheric refraction positioning error of optical remote sensing satellite images in the Tibetan Plateau region. First, the Tibetan Plateau region Based on meteorological data based on historical ground observations, a spherical atmospheric model for the Tibetan Plateau region was created by performing numerical fitting of the temperature, barometric pressure, and water vapor pressure intensity parameters of the atmosphere in the Tibetan Plateau region according to changes in atmospheric altitude. build; Next, stratification of the atmosphere is performed based on the preset levels, and the atmospheric refractive index of each layer is calculated based on the values after fitting; Then, calculate the refraction angle of the initial altitude, and based on this, calculate the refraction angle of the lowest layer of the atmosphere downward in order for each layer; Calculate the ground atmosphere refraction error based on the lowest layer atmospheric refraction angle; Again, the position fixation of the satellite image is corrected based on the ground atmosphere refraction error. It can be applied to the special climate of the Tibetan Plateau region, and by calculating the atmospheric refractive index for each floor level based on changes in atmospheric altitude, the satellite's position fixation error can be accurately determined and corrected.

Description

Method for correcting atmospheric refraction positioning error of optical remote sensing satellite images in the Tibetan Plateau region {ATMOSPHERIC REFRACTION POSITIONING ERROR CORRECTION METHOD FOR OPTICAL REMOTE SENSING SATELLITE IMAGE IN QINGHAI-TIBET PLATEAU REGION}

The present invention relates to satellite remote sensing technology, and in particular, to a technology for correcting position fixation errors in optical remote sensing satellite images.

Satellite remote sensing technology has great application value in numerous fields such as politics, economy, military, and society, and is currently a popular technology being developed in each country. Remote sensing satellite platforms are located outside the Earth's atmosphere, and when light propagation passes through the Earth's atmosphere, changes in air density cause bending near the surface, which is called the atmospheric refraction effect. Especially in situations where the satellite side view is relatively large, this refraction has a relatively large impact on the position fixation of the optical remote sensing satellite. Because the Earth's atmospheric layer is heterogeneous, its density and distribution change depending on the influence of various factors such as time, space, and geographical location, and this error has a very large uncertainty.

Fixing the geometric position of optical remote sensing satellite images is based on the principle of collinearity equation during imaging surveying, recovers the imaging rays through internal and external orientation elements to determine the image, and builds a detailed geometric model of the image to determine the angle of the image. Determine the object space location of the image point. Atmospheric refraction changes the straight propagation direction between the satellite and the ground of the feature-reflected light, and destroys the collinear conditions of the feature point, the imaging load perspective center, and the CCD sensor, resulting in a constant atmospheric refraction error in the precise geometric position fixation result formed based on the collinear equation. occurs. Currently, with the development of optical ultra-high-resolution satellite technology, there are more and more satellites with resolutions of 0.5 m or less, and in situations where the side view is relatively large, the atmospheric refraction error far exceeds 1 pixel, so visibility must be corrected.

The prior art mainly simplifies the Earth's atmosphere into a single-layer model of a single-layer spherical atmosphere (Noerdlinger 1999; Oh and Lee 2011), and simplifies the Earth's atmosphere into a two-layer model of the troposphere and stratosphere (Yan et al. 2016). In the single-layer model and the two-layer model, it was determined that the same atmosphere had the same refractive index. According to Snell's Law, the refraction angle of the light ray from the satellite to the ground is calculated and observed, and finally the atmospheric refraction error is calculated.

First, the atmospheric refractive index is mainly affected by changes in atmospheric density, but atmospheric density is also closely related to atmospheric temperature, pressure intensity, and water vapor parameters. At the same time, these parameters are always closely related to atmospheric altitude. Current calculation methods simply view the atmosphere as a single or double layer and assume that the atmospheric refractive index is fixed in the same layer. However, those skilled in the art should note that since atmospheric altitude changes continuously during the propagation of light rays, changes in atmospheric refractive index will also occur continuously. Current calculation methods do not reflect these characteristics, so certain model errors exist.

Next, the current calculation method typically proceeds with modeling according to atmospheric meteorological conditions according to mid-latitude standards. However, the Tibetan Plateau region of China (located between 26°00′~39°47′N latitude and 73°19′~104°47′E longitude) has special climate and atmospheric conditions, and atmospheric conditions and There is a relatively noticeable difference from the standard standby mode. If the standard atmospheric model is still used to calculate the atmospheric refraction error of optical remote sensing images of the Tibetan Plateau region, it will be very difficult to obtain theoretically satisfactory results.

The purpose of the present invention is to meet the special climate of the Tibetan Plateau region and calculate the atmospheric refractive index for each floor height based on changes in atmospheric altitude to accurately determine the satellite positioning error and correct the error. The purpose is to provide a method for correcting atmospheric refraction positioning error of optical remote sensing satellite images.

The present invention uses the following technical solution to solve the above technical problem.

The method for correcting atmospheric refraction position fixation error in optical remote sensing satellite images in the Tibetan Plateau region includes the following steps.

Step 1: Based on meteorological data based on historical ground observations in the Tibetan Plateau region, numerical fitting is performed on the temperature, barometric pressure, and water vapor pressure intensity parameters of the Tibetan Plateau region according to changes in atmospheric altitude. Build a regional spherical atmospheric model;

Step 2: Perform stratification of the atmosphere based on the preset levels, and calculate the atmospheric refractive index of each layer based on the values after fitting;

Step 3: Calculate the refraction angle of the initial altitude, and based on this, calculate the refraction angle of the lowest layer of the atmosphere in descending order for each layer;

Step 4: Calculate the ground atmospheric refraction error based on the lowest layer atmospheric refraction angle;

Step 5: Correct the position fixation of the satellite image based on the ground atmosphere refraction error.

In detail, in step 1, numerical fitting is performed according to changes in atmospheric altitude for the temperature, barometric pressure, and water vapor pressure intensity parameters of the atmosphere in the Tibetan Plateau region.

When the atmospheric altitude H is 0-11(km),

T(K)=-5.85473×H+305.549;

P(Pa)=9740×exp(-((H+41.29)/27.35) ² );

e(Pa)=194.2×exp(-((H+11.88)/8.654) ² );

When the atmospheric altitude H is 11-17(km),

T(K)=-6.317868×H+308.321;

P(Pa)=2501×exp(-((H+21.3)/21.3) ² );

e(Pa)=1183×exp(-0.8605×H);

When the atmospheric altitude H is 17-30 (km),

T(K)=2.54×H+156.4;

P(Pa)=1985×exp(-0.2286×H)+537.7×exp(-0.1313×H);

e(Pa)=-0.000001378×H ³ +0.00009408×H ² -0.002092×H+0.01566;

When the atmospheric altitude H is 30-100(km),

T(K)=0.00008621×H ⁴ -0.01916×H ³ +1.429×H ² -41.91×H+651.7;

P(Pa)=3.956420×[214.65/(214.65-2×(h-71))] ^(34.1632/-2) ;

e(Pa)=0.1393×exp(-0.1968×H);

Here, T represents temperature, H represents atmospheric altitude, P represents atmospheric pressure intensity, and e represents water vapor pressure intensity.

In detail, in step 2, the formula for calculating the refractive index of the atmosphere in any one layer is:

ego;

From here,

ego;

T is temperature, H is atmospheric altitude, P is atmospheric pressure intensity, denotes the water vapor pressure intensity, all of which can be found from the numerical fitting table, where: is the group refraction, is the atmospheric refractive index, is the phase refraction, is the phase refractive index, is the optical wavelength.

In detail, in step 2 above, the preset level difference is 100 meters.

In detail, step 3 includes the following steps.

Step 31: Emit a beam of light from the satellite sensor location to determine altitude. up to 0.5 satellites Refraction occurs when a point is reached at a distance of Assuming that, the unit vector of the incident ray is,

ego;

The equation of the straight line corresponding to the incident ray is:

ego;

From here, , , indicates satellite altitude;

Step 32: When constructing a centrifuge centered on the Earth, The equation of a circle with radius is,

ego;

From here, ego, denotes the altitude interval in the stratification of the adjacent atmosphere, denotes the Earth's radius;

Simultaneous equations:

obtain;

Step 33: Calculate the angle of refraction of the incident ray, where the command vector is , and the unit vector is ego, and vector The chelicerae of In case, is established, and in this case,

and;

Step 34: Calculate the refraction angle of the incident ray of the next layer, based on the law of refraction,

is established;

ego;

From here, class represents the atmospheric refractive index of the first layer and the atmospheric refractive index of the second layer, respectively;

Step 35: Calculate the angle of refraction of the next layer of atmosphere, Repeat the above steps using as the angle of incidence for the next layer, and calculate the refraction angle of the atmosphere at each layer in turn; Calculate the angle of refraction in the lowest atmosphere when light rays intersect the Earth's surface.

Furthermore, in step 4 above, calculating the ground atmosphere refraction error based on the lowest atmosphere refraction angle includes the following steps in detail.

Assuming that this is the actual location where the ray reaches the ground, is the position at which the light ray intersects the ground along a straight path, unaffected by atmospheric refraction; The error caused by atmospheric refraction at the ground is And the Earth has a radius of It is close to a circular sphere, and constructs a two-dimensional rectangular coordinate system. The y-axis is from the Earth's centripetal to the satellite, the zenith direction is the positive direction, the direction perpendicular to the y-axis is the x-axis, the east direction is the positive direction, and N is the satellite. In the case of a point directly below , The centrifugal angle corresponding to is ego, The centrifugal angle corresponding to In this case, the atmospheric refraction error size is,

am.

Going further, in step 5 above, assuming that the point P of the image is located in an earth-centered, earth-fixed (ECEF) coordinate system and that the coordinates in the coordinate system are (x, y, z), the satellite azimuth silver And the calculation formula to correct the position fixation of the satellite image based on the ground atmosphere refraction error is,

am.

The present invention achieves the following beneficial effects. The method of the present invention is based on meteorological data based on historical ground observations in the Tibetan Plateau region and performs numerical fitting of the temperature, barometric pressure, and water vapor pressure intensity parameters of the atmosphere in the Tibetan Plateau region according to changes in atmospheric altitude. By building a spherical atmospheric model for the Tibetan Plateau region, the atmospheric refractive index for each floor height can be calculated in real time based on the fitting values. Based on 100 m elevation intervals, continuous stratification of the atmospheric layer is performed. Since the change in altitude difference is small at 100 m, the atmospheric refractive index can be judged to be the same within the vertical cross-section range of 100 m. When calculating the atmospheric refractive index by floor height through stratification, the refraction angle of each layer of the incident ray is more accurately determined, and by finally calculating the refraction angle of the ray and the ground, the error in satellite position fixation can be accurately determined and precise correction can be made. You can.

1 is an explanatory diagram of ray vector refraction in multilayer atmosphere according to Embodiment 1 of the present invention;
Figure 2 is a correction diagram for refractive error of image coordinate values according to Embodiment 1 of the present invention;
Figure 3 shows atmospheric refraction error results under different side viewing angles according to Example 2 of the present invention;
Figure 4 shows a diagram of image position fixation error according to Example 3 of the present invention.

Hereinafter, the technical solution of the present invention will be described in detail by combining examples and drawings.

The method for correcting the position fixation error of optical remote sensing satellite images in the Tibetan Plateau area according to the present invention is,

First, based on meteorological data based on historical ground observations in the Tibetan Plateau region, numerical fitting was performed on the temperature, barometric pressure, and water vapor pressure intensity parameters of the atmosphere in the Tibetan Plateau region according to changes in atmospheric altitude. Build a spherical atmospheric model of;

Next, stratification of the atmosphere is performed based on the preset levels, and the atmospheric refractive index of each layer is calculated based on the values after fitting;

Then, calculate the refraction angle of the initial altitude, and based on this, calculate the refraction angle of the lowest layer of the atmosphere downward in order for each layer;

Calculate the ground atmosphere refraction error based on the lowest layer atmospheric refraction angle;

Again, the position fixation of the satellite image is corrected based on the ground atmosphere refraction error.

Conventional technologies typically perform modeling according to atmospheric meteorological conditions according to mid-latitude standards. However, due to the special climate and atmospheric environment in the Tibetan Plateau region of China, there are relatively clear differences in atmospheric conditions and standard atmospheric modes. If the standard atmospheric model is still used to calculate the atmospheric refraction error of optical remote sensing images of the Tibetan Plateau region, it will be very difficult to obtain theoretically satisfactory results. The present invention applies to the Tibetan Plateau region and presents a method for accurately calculating the refractive error of the multilayer atmosphere based on changes in atmospheric altitude. In atmospheric modeling, this method takes into account the special climate and characteristics of the atmospheric environment of the Tibetan Plateau and performs joint modeling by combining actual meteorological data and standard models; At the same time, in building a geometric model of atmospheric refractive error, the present invention carries out continuous stratification of the atmospheric layer according to the fixed altitude difference, which can further reflect the continuous change of atmospheric refractive index and is theoretically more precise. . By applying the present invention to directly calculate the atmospheric refraction correction value of the image point with respect to the ground, the image position fixation accuracy of the optical remote sensing satellite for the Tibetan Plateau region can be directly improved.

Example 1

This embodiment mainly includes two parts: the first part builds a fitting model in which the temperature, pressure intensity, and water vapor pressure intensity in the Tibetan Plateau region change with altitude; The second part builds a dense geometric correction model for ray vector refraction error based on atmospheric continuous stratification.

In the first part of building a fitting model in which the temperature and pressure intensity of the atmosphere in the Tibetan Plateau region change with altitude,

Because the Tibetan Plateau has relatively distinct regional characteristics in terms of topography and climate, there are relatively clear differences in atmospheric conditions and standard atmospheric modes, and the standard atmospheric model can still be used to calculate the atmospheric refraction error of optical remote sensing images in the Tibetan Plateau region. In this case, it will be very difficult to obtain theoretically satisfactory results. It is very necessary to improve the precision of satellite image position fixation by building a zonal atmospheric model and calculating atmospheric refraction error. This example is based on 10 years of accumulated ground observation meteorological data from 11 ground-based stations in the Tibetan Plateau region and refers to mid-latitude and tropical atmospheric models to estimate the temperature, pressure, and water vapor pressure intensity parameters of the atmosphere in the Tibetan Plateau region, as well as changes in atmospheric altitude. By performing numerical fitting based on , we derived the formula below.

Table 1 Numerical fitting table of temperature, barometric pressure and water vapor pressure intensity in the Tibetan Plateau region.

The formula used to calculate atmospheric density is:

(kg/m ³ ) (1),

is the gas constant, and the magnitude is =287.053 J·kg ^-1 ·K ^-1 .

In this example, the designated standard atmospheric environment for visible and near-infrared frequencies is temperature T = 273.15 K, atmospheric pressure intensity P = 1013.25 hPa, CO ₂ content x = 0.0375%, and the formula for calculating the group refraction of the atmosphere: silver,

(2),

e is the atmospheric water vapor pressure intensity and the unit is hPa.

Here, the formula for calculating the atmospheric phase refraction N _sph is:

(3),

T is temperature, H is atmospheric altitude, P is atmospheric pressure intensity, denotes the water vapor pressure intensity, all of which can be found from the numerical fitting table, where: is the group refraction, is the atmospheric refractive index, is the phase refraction, is the phase refractive index, is the optical wavelength.

This example uses equation (2) and combines the fitting values to calculate the atmospheric refraction coefficient for each layer.

In the second part, building a dense geometric correction model for ray vector refraction error based on atmospheric continuous stratification,

This example uses continuous stratification of the atmospheric layer based on 100 m elevation intervals. Since the change in altitude difference of 100 m is small, it can be judged that the atmospheric refractive index is the same within the vertical cross-section range of 100 m.

In this example, the method of calculating atmospheric light refraction is as shown in Figure 1. As the air density gradually increases when the light ray enters the atmospheric layer, the atmospheric refraction coefficient gradually increases, and the light propagation path becomes a curved continuous line. It changes. is the actual position where the ray reaches the ground, is the position where the light ray intersects the ground along a straight path without being affected by atmospheric refraction. As can be seen from this, the error caused by atmospheric refraction at the ground is , It is a curved line of a section of the Earth's surface. The Earth has a radius is close to a circular sphere, constructing a two-dimensional rectangular coordinate system, S from the Earth's centripetal to the satellite is the y-axis, the zenith direction is the positive direction, the direction perpendicular to the y-axis is the x-axis, the east direction is the positive direction, and N If it is the direct point of this satellite, The centrifugal angle corresponding to is ego, The centrifugal angle corresponding to In this case, the atmospheric refraction error size is,

(4),

Here, as shown in Figure 1, , am.

_{The ​ ​} Is,

(5),

Δh is the altitude difference between adjacent elevation refractive surfaces, and this example calculates the atmospheric refractive index based on the altitude difference every 100 meters. Within the range of 100 meters altitude difference, it can be determined that the atmospheric refractive index does not change.

The propagation process of light rays in the multilayer atmosphere is as shown in Figure 1, and in the technical procedure for specifically calculating a detailed geometric correction model of multilayer atmospheric refraction,

1. Straight line equation that determines the incident ray

It emits a beam of light from the satellite sensor location to determine altitude up to 0.5 satellites When reaching a point at a distance of , refraction occurs and lateral vision changes. Assuming that, the unit vector of the incident ray is,

(6),

The equation of the straight line corresponding to the incident ray is:

； （7）,

From here, , , displays the satellite altitude.

2. Calculate the intersection position of the incident ray and the concentric sphere

Build a centripetal center with the Earth as its centripetal center, The equation of a circle with a radius is the equation of a circle with a radius,

; (8) and

From here, ego, denotes the altitude interval in the stratification of the adjacent atmosphere, indicates the mechanism radius.

By simultaneous equations (7) and (8),

get

3. Calculate the angle of refraction of the incident ray

Command vector If , the unit vector is and vector and vector The chelicerae of In case, And in this case,

；（9).

4. Calculate the angle of refraction of the incident ray

Based on the law of refraction (Snell's law),

(10),

It is (11).

5. Lower the elevation by Δh and calculate the refraction angle of the next elevation plane.

Take as the next angle of incidence and repeat steps 1 to 4 to obtain the refraction angle of each elevation plane. Calculate in order.

6. Calculate the final angle of refraction when the ray intersects the Earth's surface.

Repeat steps 1 to 4 until H=0 and finally Obtain and substitute into formula (4) to calculate the ground atmosphere refraction error d.

Finally, corrections are made to fix the position of the high-resolution satellite image.

7. Assuming that point P in the image is located in the earth-centered, earth-fixed coordinate system (ECEF) and that the coordinates in the coordinate system are (x,y,z), the satellite azimuth is In this case, the calculation for the atmospheric refraction correction value is as shown in Figure 2, and the calculation formula is Formula 12:

It is (12).

Example 2

To confirm the practicality and superiority of the present invention, this example calculates the atmospheric refractive error for each side view.

First, under the condition that the satellite trajectory altitude is 650km and the Earth's average radius is 6371km, the atmospheric refraction coefficient is calculated by blue light with a central wavelength of 0.5μm, and an interval of 5° is used using equations (1) to (10). Calculate the geometric position fixation deviation where atmospheric refraction occurs within a lateral visual range of 15° to 45°, and calculate atmospheric refraction in the single-layer atmosphere from the literature (Noerdlinger 1999) and the double-layer atmosphere from the literature (Ming et al. 2016). Contrast with the geometric deviation of , the results are as shown in Figure 3.

Based on the experimental results in Figure 3, it can be analyzed as follows.

1. When the side visual angle is less than 30°, the calculation results of the standard atmospheric model using the algorithm of the present invention and the results using the single-layer method and the double-layer method in the reference literature are basically consistent.

2. When the side visual angle is greater than 30°, the difference between the calculation results calculated by the three methods gradually increases, and the results calculated by the algorithm of the present invention are more accurate. The atmospheric refraction error is largest for the two-layer method and smallest for the single-layer method, and the method of the present invention lies between the two. When analyzed, the cause is as follows. The present invention calculates the atmospheric refraction coefficient and the corresponding refraction deviation of the line of sight through atmospheric continuous stratification using the line of sight of the satellite sensor as a starting point; The two-layer method is also calculated using the line of sight of the satellite sensor as a starting point, and calculates the refraction coefficients of the troposphere and stratosphere based on a weighted average algorithm. In reality, the change in atmospheric refraction coefficient is not linear in the troposphere and stratosphere. The weighted average method cannot accurately reflect these changes. In particular, when the altitude is higher than 11 km, the top layer of the troposphere transitions to the stratosphere, and in this case, the atmospheric refraction coefficient accelerates and decreases. The two-layer method estimates the atmospheric refraction error, and the single-layer method uses the troposphere and stratosphere as a single-layer atmospheric model to calculate the atmospheric refraction error. This hypothesis also underestimates the actual change in atmospheric refraction coefficient. The algorithm of the present invention stratifies the atmospheric layers based on the altitude change value every 100 meters, continuously calculates the atmospheric refraction coefficient of each layer and the corresponding refraction angle, and, as can be seen from the geometric principles of light propagation, The invention is a precise calculation method, so the calculation results are more accurate.

Example 3

This example experiments using high-resolution satellite images of the Tibetan Plateau region.

In terms of the practical use effect of the present invention, this example conducts an experiment on panchromatic images with a resolution of 0.5 meters from the WorldView-2 satellite in the quadruple Tibetan Plateau region, and the image coverage area is 95°41′17.19″~96°E. Located at °01′45.24″, 36°07′46.54″~36°19′57.60″N, the administrative district is within the territory of Dulan County, Qinghai, and the Caidam Basin. Located on the southern outskirts of and on the northern slope of the middle section of Kunlun Mountain, the area is a deeply carved alpine area, the altitude is between 3300 and 4500 meters, and the relative altitude difference is around 300 to 800 meters. Basic information of the video is as described in Table 3.

Table 2 Basic information of high-resolution satellite imaging experiments in the Tibetan Plateau region

In the above image coverage area, 80 ground inspection points are artificially distributed unevenly, and field surveying is conducted outdoors using GPS technology, and the planar precision and elevation precision of the inspection points are better than 5cm.

An experiment was conducted on image position fixation precision using four methods: the first was calculated using the image provider's Rational Function Model (RFM) and no atmospheric refraction correction was performed; The second used the single layer method; The third time used the two-layer method; Fourth, the calculation method of the present invention was used.

Based on the remote sensing image position fixation model, the difference between the model calculated position P(X,Y,Z) of the inspection point and the known coordinates P ₀ (X ₀ ,Y ₀ ,Z ₀ ) is calculated, and e is WGS84 Indicates the point error in the spatial rectangular coordinate system. In this case, the calculation formula for e is:

(13),

Based on the error of each inspection point in the image of each width, the average error value and root mean square error (RMSE) are calculated.

As can be seen from Figure 4, in the images of the experimental area, the precision of image position fixation using the method of the present invention is the highest. Here, the image position fixation accuracy of the four widths of the experimental area was improved by 18% on average; Compared to the current calculation method, the precision of the calculation method of the present invention was improved by an average of 11%. The current results were obtained only in situations where the side visual angle is less than 32°, and as the side visual angle increases, the superiority of the calculation method of the present invention appears to become more evident.

Overall, optical high-resolution satellite remote sensing is an important component of ground observation technology, and has important application value in various aspects of the national economy and society, and atmospheric refraction error has a relatively large impact on the precision of optical remote sensing satellite positioning fixation. It's crazy. The calculation method of the prior art was too simple in its description of the atmospheric layer stratification model and overlooked the feature that the atmospheric refractive index continuously changes, but the present invention calculates the atmospheric refractive index and refraction angle using the altitude difference change every 100 meters to calculate the actual radio wave observed by rays. The route was described more accurately; At the same time, for the special meteorological conditions of the Tibetan Plateau region, the atmospheric light refraction coefficient is calculated using a zonal meteorological model, so that the calculation results are more accurate, and the optical high-resolution satellite image shows the actual positioning accuracy of the image shown in the region. improve

Claims (7)

In the method for correcting atmospheric refraction position fixation error of optical remote sensing satellite images in the Tibetan Plateau region,
The following steps,
Step 1: Based on meteorological data based on historical ground observations in the Tibetan Plateau region, numerical fitting is performed on the temperature, barometric pressure, and water vapor pressure intensity parameters of the Tibetan Plateau region according to changes in atmospheric altitude. building a regional spherical atmospheric model;
Step 2: Performing stratification of the atmosphere based on preset levels and calculating the atmospheric refractive index of each layer based on the values after fitting;
Step 3: Calculate the refraction angle of the initial altitude, and based on this, calculate the refraction angle of the lowest layer of the atmosphere in descending order for each layer;
Step 4: Calculating ground atmospheric refraction error based on the lowest layer atmospheric refraction angle;
Step 5: Correcting the position fixation of the satellite image based on the ground atmospheric refraction error; A method of correcting the atmospheric refraction position fixation error of the optical remote sensing satellite image in the Tibetan Plateau region, comprising: According to paragraph 1,
In step 1, numerical fitting is performed in detail for the temperature, barometric pressure, and water vapor pressure intensity parameters of the atmosphere in the Tibetan Plateau region according to changes in atmospheric altitude,
When the atmospheric altitude H is 0-11(km),
T(K)=-5.85473×H+305.549;
P(Pa)=9740×exp(-((H+41.29)/27.35) ² );
e(Pa)=194.2×exp(-((H+11.88)/8.654) ² );
When the atmospheric altitude H is 11-17(km),
T(K)=-6.317868×H+308.321;
P(Pa)=2501×exp(-((H+21.3)/21.3) ² );
e(Pa)=1183×exp(-0.8605×H);
When the atmospheric altitude H is 17-30 (km),
T(K)=2.54×H+156.4;
P(Pa)=1985×exp(-0.2286×H)+537.7×exp(-0.1313×H);
e(Pa)=-0.000001378×H ³ +0.00009408×H ² -0.002092×H+0.01566;
When the atmospheric altitude H is 30-100 (km),
T(K)=0.00008621×H ⁴ -0.01916×H ³ +1.429×H ² -41.91×H+651.7;
P(Pa)=3.956420×[214.65/(214.65-2×(h-71))] ^(34.1632/-2) ;
e(Pa)=0.1393×exp(-0.1968×H);
Here, T is temperature, H is atmospheric altitude, P is atmospheric pressure intensity, and e is water vapor pressure intensity. Atmospheric refraction position fixation error correction method of optical remote sensing satellite images in the Tibetan Plateau region. According to paragraph 2,
In step 2, the formula for calculating the refractive index of the atmosphere in any one layer is:
ego;
From here,
ego;
T is temperature, H is atmospheric altitude, P is atmospheric pressure intensity, denotes the water vapor pressure intensity, all of which can be found from the numerical fitting table, where: is the group refraction, is the atmospheric refractive index, is the phase refraction, is the phase refractive index, Method for correcting atmospheric refraction position fixation error of optical remote sensing satellite images in the Tibetan Plateau region, characterized in that the optical wavelength is. According to claim 1 or 2 or 3,
In step 2, a method for correcting atmospheric refraction position fixation error of optical remote sensing satellite images in the Tibetan Plateau region, characterized in that the preset level difference is 100 meters. According to clause 4,
Step 3 is the following steps,
Step 31: Emit a beam of light from the satellite sensor location to determine altitude. up to 0.5 satellites Refraction occurs when a point is reached at a distance of Assuming that, the unit vector of the incident ray is,
ego;
The equation of the straight line corresponding to the incident ray is:
ego;
From here, , , indicates satellite altitude;
Step 32: When constructing a centrifuge centered on the Earth, The equation of a circle with radius is,
ego;
From here, ego, denotes the altitude interval in the stratification of the adjacent atmosphere, denotes the Earth's radius;
Simultaneous equations:
obtain;
Step 33: Calculate the angle of refraction of the incident ray, where the command vector is , and the unit vector is ego, and vector The chelicerae of In case, is established, and in this case,
and;
Step 34: Calculate the refraction angle of the incident ray of the next layer, based on the law of refraction,
is established;
ego;
From here, class represents the atmospheric refractive index of the first layer and the atmospheric refractive index of the second layer, respectively;
Step 35: Calculate the angle of refraction of the next layer of atmosphere, Repeat the above steps using as the angle of incidence for the next layer, and calculate the refraction angle of the atmosphere at each layer in turn; A method for correcting atmospheric refraction position fixation error of optical remote sensing satellite images in the Tibetan Plateau region, comprising calculating the refraction angle of the lowest layer of the atmosphere when a light ray intersects the Earth's surface. According to clause 5,
In step 4 above, calculating the ground atmospheric refraction error based on the lowest layer atmospheric refraction angle is detailed in the following steps,
Assuming that this is the actual location where the ray reaches the ground, is the position at which the light ray intersects the ground along a straight path, unaffected by atmospheric refraction; The error caused by atmospheric refraction at the ground is And the Earth has a radius of It is close to a circular sphere and constructs a two-dimensional rectangular coordinate system. The y-axis is from the Earth's centripetal to the satellite, the zenith direction is the positive direction, the direction perpendicular to the y-axis is the x-axis, the east direction is the positive direction, and N is the satellite. If it is a point directly under , The centrifugal angle corresponding to is ego, The centrifugal angle corresponding to In this case, the atmospheric refraction error size is,
A method for correcting atmospheric refraction position fixation error of optical remote sensing satellite images in the Tibetan Plateau region, comprising the step of: According to clause 6,
In step 5 above, assuming that point P of the image is located in an earth-centered, earth-fixed coordinate system (ECEF) and that the coordinates in the coordinate system are (x, y, z), the satellite azimuth is And the calculation formula to correct the position fixation of the satellite image based on the ground atmosphere refraction error is,
A method for correcting atmospheric refraction position fixation error of optical remote sensing satellite images in the Tibetan Plateau region, characterized in that: