阅读说明：本技术 一种点源靶标反射镜的调整角度计算方法 (Method for calculating adjustment angle of point source target reflector ) 是由 李凯 张永生 杨伟铭 童晓冲 郭磊 纪松 赖广陵 于 2020-06-09 设计创作，主要内容包括：本发明属于遥感技术领域,具体涉及一种点源靶标反射镜的调整角度计算方法。该方法首先获取卫星过顶时刻的卫星位置,并结合点源靶标位置,确定点源靶标指向卫星的单位矢量；然后获取太阳的方位角和高度角,确定点源靶标指向太阳的单位矢量；接着根据点源靶标指向卫星的单位矢量和点源靶标指向太阳的单位矢量,确定点源靶标反射镜调整后的法线指向向量,进而得到点源靶标反射镜应调整的高度角和方位角。参照该角度对点源靶标反射镜的角度进行调整,可使卫星过顶点源靶标时,太阳光线经点源靶标反射镜反射后进入传感器的入瞳处。使点源靶标在遥感卫星影像上生成高质量点源影像,用于遥感传感器在轨几何定标和辐射定标。(The invention belongs to the technical field of remote sensing, and particularly relates to a method for calculating an adjustment angle of a point source target reflector. Firstly, acquiring the satellite position of a satellite at the moment of satellite passing the top, and determining a unit vector of a point source target pointing to the satellite by combining the point source target position; then acquiring the azimuth angle and the elevation angle of the sun, and determining a unit vector of the point source target pointing to the sun; and then, according to the unit vector of the point source target pointing to the satellite and the unit vector of the point source target pointing to the sun, determining the normal pointing vector after the point source target reflector is adjusted, and further obtaining the altitude angle and the azimuth angle of the point source target reflector to be adjusted. The angle of the point source target reflector is adjusted according to the angle, so that when the satellite passes through the top point source target, sunlight rays enter the entrance pupil of the sensor after being reflected by the point source target reflector. The point source target generates a high-quality point source image on the remote sensing satellite image, and the high-quality point source image is used for on-orbit geometric calibration and radiometric calibration of the remote sensing sensor.)

1. A method for calculating an adjustment angle of a point source target reflector is characterized by comprising the following steps:

acquiring the satellite position of the satellite at the moment of satellite passing the top, and determining a unit vector of the point source target pointing to the satellite by combining the point source target position;

acquiring the azimuth angle and the elevation angle of the sun, and determining a unit vector of a point source target pointing to the sun;

determining a normal pointing vector after the point source target reflector is adjusted according to the unit vector of the point source target pointing to the satellite and the unit vector of the point source target pointing to the sun;

and determining the altitude angle and the azimuth angle of the point source target reflector to be adjusted according to the normal unit pointing vector of the point source target reflector after adjustment.

2. The method for calculating the adjustment angle of the point source target reflector according to claim 1, further comprising loading the obtained height angle and azimuth angle to be adjusted by the point source target reflector to a driving device of the point source target reflector, so that the driving device drives the point source target reflector to operate according to the height angle and azimuth angle to be adjusted by the point source target reflector.

3. The method for calculating the adjustment angle of the point source target reflector according to claim 1, wherein the normal unit pointing vector after the adjustment of the point source target reflector is a vector in a northeast coordinate system.

4. The method for calculating the adjustment angle of the point source target reflector according to any one of claims 1 to 3, wherein the normal unit pointing vector after the adjustment of the point source target reflector is:

in the formula (I), the compound is shown in the specification,the normal unit pointing vector after the point source target reflector is adjusted,

5. The method for calculating the adjustment angle of the point source target reflector according to any one of claims 1 to 3, wherein if the normal unit pointing vector of the point source target reflector after adjustment is as followsThen:

the height angle that the point source target reflector should adjust does:

H_mir＝arcsinc

when b is larger than 0, the azimuth angle of the point source target reflector to be adjusted is as follows:

when b is less than 0 and a is less than 0, the azimuth angle of the point source target reflector to be adjusted is as follows:

when b is less than 0 and a is more than 0, the azimuth angle of the point source target reflector to be adjusted is as follows:

in the formula, H_mirElevation angle to be adjusted for point source target reflector, A_mirThe azimuth angle that the reflector should adjust for the point source target.

6. The method of calculating the adjustment angle of a point source target mirror according to claim 3, wherein the unit vector of the point source target pointing to the satellite is:

in the formula (I), the compound is shown in the specification,a unit vector pointing to a satellite for a point source target, (X, Y, Z) is the satellite position in a northeast coordinate system, (X)₀,Y₀,Z₀) The target position of the point source under the coordinate system of the northeast is shown.

7. The method of calculating the adjustment angle of a point source target reflector according to claim 3, wherein the unit vector of the point source target pointing to the sun is:

in the formula (I), the compound is shown in the specification,unit vector pointing to the sun for a point source target, H_sunIs the altitude of the sun, A_sunIs the azimuth angle of the sun.

Technical Field

The invention belongs to the technical field of remote sensing, and particularly relates to a method for calculating an adjustment angle of a point source target reflector.

Background

With the development of science and technology, remote sensing technology is mature day by day and is applied to various aspects in life. The remote sensing technology is a comprehensive technology for detecting and identifying various scenes on the ground by collecting, processing and finally imaging electromagnetic wave information radiated and reflected by a remote target according to an electromagnetic wave theory. The electromagnetic wave information reflected by the target is received by a sensor of a remote sensor, an optical signal is converted into an electric signal, and a corresponding number is obtained by processing the electric signal by a circuit system, wherein the number is called DN (digital number). These numbers can be converted to real world units such as radiance, reflectance, or luminance temperature.

The transmission process of light among the sun 1, the point source target reflector 2 and the remote sensing satellite sensor 3 in the remote sensing optical imaging system is shown in figure 1, and the sunlight enters the entrance pupil of the remote sensing satellite sensor after being reflected by the point source target reflector through the positions among the sun 1, the point source target reflector 2 and the remote sensing satellite sensor 3. In order to realize the on-orbit joint geometric and radiometric calibration of the remote sensing sensor, a high-quality point source image needs to be generated on the remote sensing satellite image by the point source target. How to accurately grasp the sunlight reflected by the point source target to obtain a high-quality point source target image is a problem which needs to be solved urgently.

Disclosure of Invention

The invention provides a calculation method for an adjustment angle of a point source target reflector, which is used for accurately mastering sunlight reflected by a point source target to obtain a high-quality point source target image.

In order to solve the technical problem, the technical scheme of the invention comprises the following steps:

the invention provides a method for calculating an adjustment angle of a point source target reflector, which comprises the following steps of:

acquiring the satellite position of the satellite at the moment of satellite passing the top, and determining a unit vector of the point source target pointing to the satellite by combining the point source target position;

acquiring the azimuth angle and the elevation angle of the sun, and determining a unit vector of a point source target pointing to the sun;

determining a normal unit pointing vector after the point source target reflector is adjusted according to the unit vector of the point source target pointing to the satellite and the unit vector of the point source target pointing to the sun;

and determining the altitude angle and the azimuth angle of the point source target reflector to be adjusted according to the normal unit pointing vector of the point source target reflector after adjustment.

The beneficial effects of the above technical scheme are: according to the invention, through the relationship among the sun, the point source target reflector and the remote sensing satellite sensor, after the unit vector of the point source target to the satellite and the unit vector of the point source target to the sun are determined, the normal unit pointing vector of the point source target reflector after adjustment can be determined, the angle of the power source target reflector to be adjusted can be determined according to the normal unit pointing vector of the point source target reflector after adjustment, the angle of the point source target reflector is adjusted according to the angle, and when the satellite passes through the peak source target, the sunlight enters the entrance pupil of the sensor after being reflected by the point source target reflector. The point source target generates a high-quality point source image on the remote sensing satellite image, and the high-quality point source image is used for on-orbit geometric calibration and radiometric calibration of the remote sensing sensor.

And further, the driving device loads the obtained altitude angle and azimuth angle which are required to be adjusted by the point source target reflector to the point source target reflector, so that the driving device drives the point source target reflector to act according to the altitude angle and azimuth angle which are required to be adjusted by the point source target reflector.

Further, the normal unit pointing vector after the point source target reflector is adjusted is a vector in a northeast coordinate system. The normal unit pointing vector after the point source target reflector is adjusted is a vector under a coordinate system in the northeast, and the angle of the point source target reflector needing to be rotated can be conveniently and quickly calculated, so that the point source target reflector can be conveniently adjusted.

Further, the normal unit pointing vector after the adjustment of the point source target reflector is as follows:

in the formula (I), the compound is shown in the specification,

the normal unit pointing vector after the point source target reflector is adjusted,is the unit vector of the point source target pointing to the sun,

a unit vector pointing to the sun for a point source target.

Further, if the normal unit pointing vector after the point source target reflector is adjusted isThen:

the height angles of the point source target reflector to be adjusted are respectively as follows:

H_mir＝arcsinc

when b is larger than 0, the azimuth angle of the point source target reflector to be adjusted is as follows:

when b is less than 0 and a is less than 0, the azimuth angle of the point source target reflector to be adjusted is as follows:

when b is less than 0 and a is more than 0, the azimuth angle of the point source target reflector to be adjusted is as follows:

in the formula, H_mirElevation angle to be adjusted for point source target reflector, A_mirThe azimuth angle that the reflector should adjust for the point source target.

Further, the unit vector of the point source target pointing to the satellite is:

in the formula (I), the compound is shown in the specification,a unit vector pointing to a satellite for a point source target, (X, Y, Z) is the satellite position in a northeast coordinate system, (X)₀,Y₀,Z₀) The target position of the point source under the coordinate system of the northeast is shown.

Further, the unit vector of the point source target pointing to the sun is:

in the formula (I), the compound is shown in the specification,

unit vector pointing to the sun for a point source target, H_sunIs the altitude of the sun, A_sunIs the azimuth angle of the sun.

Drawings

FIG. 1 is a schematic diagram of the transmission of light between the sun, a point source target reflector and a remote sensing satellite sensor according to the prior art;

FIG. 2 is a flow chart of a method of calculation of the adjustment angle of a point source target mirror of the present invention;

FIG. 3 is a schematic representation of the solar altitude and solar azimuth of the present invention;

FIG. 4 is a schematic view of the elevation and azimuth angles in the northeast coordinate system of the present invention;

the system comprises a 1-sun, a 2-point source target reflector and a 3-remote sensing satellite sensor.

Detailed Description

The invention discloses a calculation method of an adjustment angle of a point source target reflector, which comprises the following steps as shown in figure 2:

step one, laying a point source target, and zeroing the position of a point source target reflector, namely, the azimuth angle (the included angle between the projection of the surface normal of the point source target reflector on the horizontal plane and the true north direction) is 0, and the elevation angle (the included angle between the surface normal of the point source target reflector and the horizontal plane) is 90 degrees. After the point source target is laid, the position of the point source target (namely the position of a point source target reflector) is measured by using an RTK (real-time kinematic) and generally provided with longitude and latitude and elevation information of the point source target under a WGS84 coordinate system, and the longitude and elevation information is converted into a lower position (X) of a northeast sky coordinate system₀,Y₀,Z₀) And serves as a point source target location.

And secondly, predicting the satellite position of the satellite over-vertex time according to the satellite ephemeris before the satellite over-vertex source target, generally providing longitude and latitude and elevation information under a GS84 coordinate system, and converting the longitude and latitude and elevation information into the lower position (X, Y and Z) of the northeast coordinate system.

Step three, according to the satellite positions (X, Y, Z) and the point source target position (X) under the northeast coordinate system₀,Y₀,Z₀) The unit vector of the point source target pointing to the satellite can be obtained

Step four, combining the images 3 and 4, according to the solar azimuth angle A under the northeast coordinate system_sunAnd the solar altitude H_sunThe unit vector of the point source target pointing to the sun can be obtained

Step five, according to the unit vector of the point source target pointing to the satelliteUnit vector of point source target pointing to sun

Obtaining the normal unit pointing vector after the point source target reflector is adjusted

Sixthly, pointing the vector according to the normal unit after the point source target reflector is adjustedObtaining the height angle H of the point source target reflector to be adjusted_mirAnd azimuth angle A_mir. Normal unit pointing vector obtained by hypothesis calculation after adjustment of point source target reflectorThe three components are a, b and c respectively, then the height angle H of the point source target reflector to be adjusted_mirAnd azimuth angle A_mirRespectively as follows:

H_mir＝arcsinc (4)

note that, the formula (5) is a formula in the case where the component b > 0.

When b is less than 0 and a is less than 0, the azimuth angle A of the point source target reflector is adjusted_mirIt should be:

when b is more than 0 and a is less than 0, the azimuth angle A of the point source target reflector is adjusted_mirIt should be:

step seven, adjusting the height angle H of the point source target reflector_mirAnd azimuth angle A_mirInformation is input to a driving mechanism of the point source target reflector, so that the driving mechanism drives the point source target reflector to act, the direction of the point source target reflector is adjusted, and light path alignment among the point source target, the sun and the satellite is realized. When the remote sensing satellite sensor passes the top, the sunlight reflected by the point source target can be accurately captured, so that the sunlight enters the entrance pupil of the remote sensing satellite sensor after being reflected by the point source target reflector, and a high-quality point source target image is obtained.

Height angle H for calculating adjustment of point source target reflector_mirAnd azimuth angle A_mirThe operation of the point source target reflector can be realized in a terminal, such as a notebook computer, and the like, and the calculated result is transmitted to a regulation and control assembly of a driving mechanism of the point source target reflector, so that the driving mechanism is controlled by the regulation and control assembly to drive the point source target reflector to act (rotate) according to the calculated H_mirAnd A_mirAnd adjusting the angle. Can also be directly carried out by regulating and controlling the component_mirAnd azimuth angle A_mirAfter the calculation is finished, the electric point source target reflector of the driving mechanism is directly controlled to act, and an additional terminal is not needed to calculate H_mirAnd A_mir。