CN111508327A - A target system in which the earth's north and south poles rapidly rotate around the geocentric axis - Google Patents

Abstract

A target system in which the north and south poles of the earth rapidly rotate around the geocentric axis belongs to the field of space optical remote sensing technology, and solves the problems of rapid rotation around the earth's axis in the north and south poles of the earth, causing rapid changes in the surface tangential speed, different directions, and unbalanced sizes. . The system includes: a polar simulation unit, an imaging simulation unit and a drive control unit; the polar simulation unit simulates the earth rotating at a latitude above 60° according to the scale, and simulates the top view of the earth; the imaging simulation unit simulates the movement of the satellite over the polar simulation unit and the anti-polarity The simulation unit is imaging; the driving control unit drives the polar simulation unit to rotate, and controls the imaging speed of the imaging simulation unit. The invention simulates the imaging situation of the North and South Pole landscapes by satellites under real conditions; it can not only simulate the shooting effect of the polar landscapes, but also has the ability to calibrate the image movement speeds formed in different regions of the polar regions, which can be obtained through specific calculations. Like the magnitude and direction of the transition velocity.

Description

A target system in which the earth's north and south poles rapidly rotate around the geocentric axis

technical field

The invention belongs to the technical field of space optical remote sensing, and in particular relates to a target system in which the earth's north and south poles rapidly rotate around the earth's central axis.

Background technique

The north and south poles of the earth are an important part of the earth's ecological environment, and they are also the thermometers of global climate change. Therefore, the scientific research and investigation of the polar regions has never stopped. In recent years, due to the unnatural activities of human beings, the problem of global warming has been intensified, the melting speed of polar glaciers has accelerated, the sea level has risen, and the ecology has been severely damaged, resulting in frequent disasters. The ecological environment of the polar regions urgently needs the attention of all human beings. However, due to its extremely cold temperature and sparse population, it is very difficult to monitor its environment. It is easy to see that space optical remote sensing technology has become the best means. The role of aerospace in polar scientific research increasingly important. However, space-based technology has the characteristics of high cost and high risk. The ground experiment and simulation before launch play a crucial role in its application, which requires the simulation system to have high fidelity and the experimental results to be real, effective and reliable. and other characteristics, thereby reducing the risk of scientific research.

Due to factors such as the earth's rotation, traditional satellite imaging is usually concentrated in areas within 65° or 70° north-south latitude, and the imaging methods are mostly sub-satellite point imaging or side-swing imaging. The two-dimensional combined velocity of the tangential velocity of the Earth's rotation changes slowly in low latitudes and is easy to measure and correct, as shown in Figure 1. However, as the latitude increases, the ground rotation velocity in the polar regions changes more and more complicated relative to the satellite motion. The size of the surrounding speed direction is different everywhere. Due to the complexity of this motion, the image shift produced by this process has a very serious impact on imaging. Conventional simulation devices cannot meet such complex simulation requirements, and there is still no effective means for such unconventional motion simulation at home and abroad. A ground demonstration system for imaging the north and south poles of the earth provides powerful guidance for the analysis of polar imaging quality. Therefore, a target system for rapidly rotating the earth's north and south poles around the geocentric axis is proposed.

SUMMARY OF THE INVENTION

In order to solve the problems existing in the prior art, the present invention provides a target system in which the north and south poles of the earth rapidly rotate around the earth's central axis, which solves the problem of the rapid rotation of the earth's north and south poles around the earth's axis, causing rapid changes in the surface tangential speed and direction. Different, uneven size, etc.

The technical scheme adopted by the present invention to solve the technical problem is as follows:

A target system that rapidly rotates around the center axis of the earth's north and south poles, the system comprises: a polar simulation unit, an imaging simulation unit and a drive control unit;

The polar simulation unit simulates the earth rotating above 60° latitude according to the scale, and simulates the top view of the earth;

The imaging simulation unit simulates the movement of a satellite over the polar region and images the polar simulation unit;

The driving control unit drives the polar simulation unit to rotate, and controls the imaging speed of the imaging simulation unit.

Preferably, the polar simulation unit includes a horizontal rotating platform, a polar model arranged on the horizontal rotating platform, and a polar target arranged on the polar model;

The imaging simulation unit includes: a camera motion track installed above the polar model, a camera frame arranged on the camera motion track, and an industrial camera installed on the camera frame;

The drive control unit includes: a drive device connected to the horizontal rotation platform and the camera frame, and a drive control device mounted on the drive device to control the rotational speeds of the horizontal rotation platform and the camera frame.

Preferably, the polar model and the polar target simulate the earth at a scale of 1:1000000.

Preferably, the content of the polar target is replaceable.

Preferably, the motion trajectory of the camera is the same as the arc of the polar model.

The beneficial effects of the present invention are as follows: the present invention confirms parameters such as the radius of curvature of the polar model, the rotational speed of the rotating platform, the camera orbit height, and the movement speed of the camera according to the scaling ratio, and builds the polar model and a specific imaging device, so that the polar model is rotated horizontally and the camera is Moving around the model on the orbit to take pictures to simulate the imaging situation of the satellites on the north and south poles in the real situation; through the target on the polar model, not only can the shooting effect of the polar scenery be simulated, but also the image formed in different regions of the polar region can be simulated. The ability to scale the moving speed can be obtained through the specific calculation to obtain the size and direction of the moving speed.

Description of drawings

Figure 1 Demonstration of traditional satellite imaging.

FIG. 2 is a schematic diagram of the relationship between the image movement speed in the Arctic region of a target system in which the earth and the north and south poles of the present invention rapidly rotate around the geocentric axis.

Fig. 3 is a side view of a target system simulation device in which the earth's north and south poles rapidly rotate around the earth's central axis according to the present invention.

FIG. 4 is a top view of a target system simulation device of the present invention in which the earth's north and south poles rapidly rotate around the geocentric axis.

In the picture: 1. Horizontal rotation platform, 2. Polar model, 3. Polar target, 4. Industrial camera, 5. Fixing device, 6. Camera motion track, 7. Driving device.

Detailed ways

The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

As shown in Figures 2 and 3, a target system for rapidly rotating the earth's north and south poles around the geocentric axis, the system includes: a polar simulation unit, an imaging simulation unit, and a drive control unit;

The polar simulation unit includes a horizontal rotation platform 1, a polar model 2 and a polar target 3;

The imaging simulation unit includes an industrial camera 4, a camera frame and a camera motion track 6;

The drive control unit includes a drive device 7 and a drive control device.

Polar Model 2 simulates the Earth above 60° latitude at a scale of 1:1000000 by default. The specific method takes the earth as a sphere, and the poles are located directly above and below. The scale of the earth model is cut at 60° latitude with the horizontal plane of the vertical axis and the upper half is taken. The radius of the bottom surface is 3.2m and the height is about 0.8m spherical cap with camber radius of 6.4m. The latitude 66.5° is where the polar circle is located, and the polar model 2 is equipped with a polar target 3 for verification and measurement.

The polar target 3 is set on the surface of the polar model 2, and can be replaced according to the experimental content. The default is a 1:1000000 scale top view of the earth, and the surface area is about 34.5 square meters. The camera can take pictures of the polar target under the condition of the earth's rotation and satellite motion, accurately simulate the imaging situation of the satellite on the ground in the polar sky, and can calibrate the image movement speed formed in different regions of the polar region.

The polar model 2 is arranged on the horizontal rotating platform 1, and is used to drive the polar model 2 to rotate. The polar model 2 is equipped with a device for fixing the polar model 2, and the lower part is provided by the driving transposition 7. The horizontal rotation platform 1 performs horizontal periodic rotation to simulate the rotation of the earth's pole around the earth's axis.

In the imaging simulation unit, the camera movement track 6 is set above the polar model 2 through the fixed structure 5, which is an arc-shaped guide rail with the same scale as the polar model 2, and the radian is the same as the upper surface of the polar model 2. The camera movement track is 6 distances from the model. The height is 0.5m, and the radius of curvature is 6.9m. The industrial camera 4 is fixed on the camera motion track 6 by the camera frame, and the industrial camera 4 is driven to move on the camera motion track 6 by the driving device, and the default speed is 0.0076m/s.

The drive unit is connected to the horizontal rotating platform 1 and the camera frame. Through the setting of the drive control device, the drive device 7 controls the rotational speed of the horizontal rotating platform 1 to keep it rotating at a constant horizontal speed, simulating the movement of the earth's rotation in the polar regions, north and south. The poles rotate in different directions; by setting the drive control device, the drive device 7 controls the industrial camera 4 to move at a uniform speed on the camera movement track 6, simulating the movement of the satellite over the pole.

Before use, first calculate the radius of curvature of the polar model 2, the rotational speed of the horizontal rotation platform 1 and the driving wheel, the distance between the camera motion track 6 and the surface of the polar model 2 and its position, and the motion speed of the industrial camera 4, which are used for debugging and simulation. Industrial Camera 4.

After confirming the control of all the devices, install the polar simulation unit, select the polar model 2 according to the scaling ratio of the simulated stereo imaging, build the arc surface support frame with the required curvature radius of the model and install it on the horizontal rotation platform 1, install the driving wheel , transmission belt, etc. to control the driving device 7 for the rotation of the rotating platform. Install the imaging simulation unit, fix both ends of the arc guide rail at the required camera motion track 6 through the fixing device 5, and install the industrial camera so that it can image the polar model 2. Input control parameters, start the drive control device, control the rotation of the polar model 2 and the movement of the industrial camera 4, and perform imaging simulation.

Taking the Arctic region as an example, the satellite is imaged in a push-broom manner, with an orbital inclination of 97°. The imaging area is shown in Figure 2. The Earth's rotation period is T=23h56min=86160s, and the average angular velocity of the rotation is

From this, the rotation period and angular velocity of the rotating platform are obtained. Taking the earth's radius R=6400km, according to the principle, it can be known that the actual speed can be calculated first, and then converted by the ratio. Then the linear velocity of the Earth's rotation at different latitudes is

The linear velocity of the earth's rotation at 60° latitude can be obtained by calculation

Similarly, the rotational speed of the polar circle is v ₂ =186m/s, and the linear speed of 75° latitude is v ₃ =121m/s.

The speed of the satellite at an orbital altitude H of 500km

then its projected velocity on the ground

According to the ratio of 1:1000000, the real linear velocity of the image movement corresponding to each point on the polar model 2 can be obtained, which is specifically:

v ₂ =0.000186m/s,

v ₃ =0.00012lm/s,

v ₀ =0.00762m/s,

v _s = 0.007067m/s

Wherein v ₀ is the running linear velocity of the industrial camera 4 on the camera motion track 6 . According to the scale, the radius of curvature of the polar model is R _p =640000/1000000 = 6.4m, and the distance between the 500km orbital height of the satellite simulation guide rail and the spherical height H _s =0.5m, and the radius of curvature is 6.9m. Install the polar model 2 according to the inclination of the camera motion track 6, fix both ends of the camera motion track 6 through the fixing device 5, and input the rotation angular velocity of the polar model 2 and the running speed of the industrial camera 4 to the drive control device, so that the system starts to work.

As shown in Figure 4, taking point A as an example, the image shift speed represented by the dotted line, the angle ρ between the earth's rotation linear speed v and the projection speed v _s , its size and direction are as follows

The combined velocity of the Earth's rotational linear velocity v and the projected velocity v _s is:

The declination angle between the resultant velocity and the direction of the satellite running velocity is:

Then the resultant velocity v _A = 0.007126m/s at point A on the model, and the direction is to the right γ _A = 1.4239°

B point speed v _B =0.007124m/s, direction to the right γ _B =0.8584°

C point speed v _C = 0.007124m/s, direction left γ _C = 0.8584°

D point speed v _D =0.007126m/s, the direction is left γ _D =1.4239°.

Claims (5)

1. A target system for rapid rotation of a north-south earth scene about a geocentric axis, the system comprising: a polar region simulation unit, an imaging simulation unit and a drive control unit;

the polar region simulation unit simulates the earth rotating at a latitude of more than 60 degrees in proportion and simulates a top view of the earth;

the imaging simulation unit simulates the satellite to move over the polar region and images the polar simulation unit;

the driving control unit drives the polar region simulation unit to rotate and controls the imaging speed of the imaging simulation unit.

2. The target system of claim 1, wherein the target system for fast rotation of the Earth's north-south polar scene about the Earth's center axis,

the polar region simulation unit comprises a horizontal rotating platform, a polar region model arranged on the horizontal rotating platform and a polar region target arranged on the polar region model;

the imaging simulation unit includes: a camera motion track mounted above the polar model, a camera frame disposed on the camera motion track, and an industrial camera mounted on the camera frame;

the drive control unit includes: the camera comprises a driving device connected with the horizontal rotating platform and the camera frame, and a driving control device arranged on the driving device and used for controlling the rotating speed of the horizontal rotating platform and the camera frame.

3. The target system of claim 2, wherein the polar model and the polar target simulate the earth on a 1:1000000 scale.

4. The target system of claim 2, wherein the contents of the polar target are replaceable.

5. The target system of claim 2, wherein the camera motion trajectory is the same arc as the polar model.

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