CN113532445A - High-dynamic rapid autonomous capturing method of roller shutter exposure star sensor - Google Patents
High-dynamic rapid autonomous capturing method of roller shutter exposure star sensor Download PDFInfo
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Abstract
A high-dynamic rapid autonomous capturing method of a rolling shutter exposure star sensor comprises the steps of firstly, selecting two frames of star maps with time variation smaller than a set time threshold; respectively calculating the difference of row coordinates, the difference of row coordinates and the distance between every two selected star points in the two frames of star maps; selecting star points from the two frames of star images and matching by using a triangular matching method; taking the star points in the two frames of star maps corresponding to the successfully matched triangles as the reference, and performing matching confirmation on the rest star points; selecting all star points which are successfully matched and confirmed in the two frames of star maps, and calculating an angular speed average value by using the position coordinates of the same star points; carrying out rolling correction on all star point positions of the current frame by using the angular velocity average value; and finally, carrying out all-day autonomous star map identification and attitude calculation by using the corrected star point coordinates. The invention effectively solves the problem of autonomous all-day capture of the roller shutter exposure star sensor under the high dynamic condition, improves the dynamic performance of the product, is suitable for all roller shutter exposure star sensors and has good engineering application value.
Description
Technical Field
The invention relates to a high-dynamic rapid autonomous capturing method of a roller shutter exposure star sensor, which is suitable for correcting the star point position of the roller shutter exposure star sensor and belongs to the technical field of satellite attitude control.
Background
The star sensor is an attitude measurement optical sensor with the highest measurement precision on the current satellite, and the star sensor does not need prior attitude and angular velocity information and carries out all-celestial-sphere autonomous attitude capture and determination. The method has the advantages of high precision, no drift, high reliability and the like, and is a key component for satellite attitude measurement. In recent years, with the continuous expansion of the application field of satellites, the requirements on the attitude measurement precision and the dynamic performance of the star sensor are higher and higher.
In order to realize higher dynamic performance superior to 5 DEG/s, 10 DEG/s and the like, the star sensor needs to select a high-sensitivity imaging detector, the available high-sensitivity detectors are all in a rolling exposure imaging mode at present, star points in the same frame star map are imaged at different moments, and errors are generated in star point imaging positions influenced by angular speed compared with actual positions. Under the condition of small dynamic, the error amount is small, and autonomous matching identification can be realized by setting a large star point matching error; however, under the condition of high dynamic, the position error of the star point can reach dozens of pixels due to the rolling exposure, and the star point can not be identified through matching, so that effective attitude data can be output. In order to enable the star sensor to meet the high-dynamic performance requirement, the rolling correction of star points is required according to the angular speed.
The star sensor has 2 working modes of an initial attitude capture mode and a tracking mode, wherein the initial attitude capture mode is to match and identify an observed star map obtained by an imaging device in the whole celestial sphere range and calculate an initial attitude; the tracking mode estimates the corresponding attitude information of the current image according to the initial attitude information, predicts the positions of star points in the star map at the current moment, then searches whether the corresponding predicted star point position areas in the observation star map have real star points or not, and then carries out local star point extraction and star map identification, thereby improving the speed of star point extraction and star map identification.
The star sensor usually works in a window tracking mode, and under the mode, the angular speed of the star sensor can be calculated according to the attitude information of two adjacent frames to finish roller blind correction. However, after the product is initialized, the product works in an all-day autonomous acquisition mode, and because the product does not have attitude prior information, the angular speed of the star sensor cannot be solved according to a tracking mode method, and the coordinates of star points are corrected. Therefore, the research on the calculation of the angular speed of the star sensor in the all-day autonomous capture mode can be suitable for the high-dynamic condition of the rolling shutter exposure star sensor so as to finish the correction of star point coordinates and the identification of an all-day star map, and is a core problem which needs to be solved urgently by the high-dynamic rolling shutter exposure star sensor.
Disclosure of Invention
The technical problem solved by the invention is as follows: the method overcomes the defects of the prior art, provides a high-dynamic rapid autonomous capturing method of the rolling-curtain exposure star sensor, and solves the problem that autonomous full-day capturing is difficult to realize when the star sensor works in a high dynamic state.
The technical scheme of the invention is as follows:
a high-dynamic rapid autonomous capturing method of a rolling shutter exposure star sensor comprises the following steps:
(1) selecting two star maps, wherein the observation time of the first star map is t1, the observation time of the second star map is t2, and the time difference threshold is set between t2 and t 1;
(2) in each star map, calculating the difference of the row coordinates, the difference of the column coordinates and the distance between every two star points;
(3) selecting three star points from the star map at the time t2 to form a star triangle according to a set difference error threshold of the row coordinates, a set difference error threshold of the column coordinates and a set distance error threshold, and selecting the star point triangle matched with the star point triangle from the star map at the time t 1;
(4) taking the star points of the successfully matched star point triangle in the two frames of star maps as a reference, and performing matching confirmation on the remaining star points;
(5) judging whether the number of matched stars is greater than 3, if so, selecting all star points successfully matched and confirmed in the two frames of star maps, calculating an angular speed average value by using the position coordinates of the same star points, and entering the step (7); otherwise, judging whether all star point triangles in the star map at the time of t2 have been traversed, if not, entering the step (6), if all star point triangles in the star map at the time of t2 have been traversed, ending, resetting the matched star number, and recording the time and star point information of the star map at the time of t2 for the next autonomous capture;
(6) continuing to search for a matched star point triangle in the star map at the time t1 and the star map at the time t2, and repeating the steps (4) to (5);
(7) performing rolling correction on the positions of all star points of the current frame by using the angular velocity average value, and entering the step (8);
(8) and performing all-day autonomous star map recognition and attitude calculation by using the corrected star point coordinates to realize rapid autonomous capture.
The step (3) is realized as follows:
(3.1) selecting three star points a, b and c from the star map at the time t2 to form a star point triangle abc, and recording the coordinate of the star point a as (u 2)a,v2a) The coordinate of the star point b is (u 2)b,v2b) The coordinate of the star point c is (u 2)c,v2c) Distance between star point a and star point b is dist2abDistance between star point b and star point c is dist2bcDistance between star point a and star point c is dist3ac；
(3.2) taking a first side ab of the star point triangle, selecting a group of observation star pairs from the star map at the time t1, wherein the observation star pairs comprise a star point m and a star point n, and the coordinate of the star point m is (u 1)m,v1m) The coordinate of the star point n is (u 1)n,v1n) Distance dist1 from the star points m and nmnIf the following conditions are satisfied:
dist1mn-dist2ab≤Thr_dist
||u1m-u1n|-|u2a-u2b||≤Thr_u
||v1m-v1n|-|v2a-v2b||≤Thr_v
adding the group of observation star pairs m and n into a matching queue 1;
wherein, Thr _ dist, Thr _ u and Thr _ v are respectively a distance error threshold, a difference error threshold of row coordinates and a difference error threshold of column coordinates;
(3.3) repeating the step (3.2) until all observation star pairs in the star map at the moment of t1 are traversed to obtain a matching queue 1;
(3.4) taking the second side bc of the star point triangle, and obtaining a matching queue 2 by referring to the methods in the steps (3.2) and (3.3);
taking a third edge ac of the star point triangle, and obtaining a matching queue 3 by referring to the methods in the steps (3.2) and (3.3);
and (3.5) searching all the star point triangles successfully matched with the star point triangles abc from the three matching queues.
In the step (3.5), the searching method is as follows:
and extracting a group of observation star pairs from each matching queue, wherein if the three groups of observation star pairs extracted from the three matching queues only contain three star points, a star point triangle formed by the three star points is successfully matched with a star point triangle abc.
In the step (3.2), the step (c),
the implementation method of the step (4) is as follows:
(4.1) let the star point triangle def in the star map at the time t1 match with the star point triangle abc in the star map at the time t2, and the three coordinates of the star point triangle abc are respectively (u 2)a,v2a)、(u2b,v2b)、(u2c,v2c) The three coordinates of the star point triangle def are respectively (u 1)d,v1d)、(u1e,v1e)、(u1f,v1f) Accordingly, the row coordinate variation delta _ u12 and the column coordinate variation delta _ v12 of two adjacent frames are calculated;
(4.2) forecasting theoretical position of ith star point at the time t1 at the time t2 (u 3) by using the calculated row coordinate variation, column left variation and star point coordinate at the time t1 of the star pointi,v3i)；
(4.3) for the ith star point at the time t1, calculating the difference between the theoretical position of the ith star point at the time t2 and the row coordinate of the Nstar2 star point at the time t2, selecting the minimum value min _ deltau of the difference between the row coordinates and the serial number idx _ minu of the star point at the time t2 corresponding to the minimum difference between the row coordinates, calculating the difference between the theoretical position of the ith star point at the time t2 and the column coordinate of the Nstar2 star point at the time t 3578, selecting the minimum value min _ deltav of the difference between the column coordinates and the serial number idx _ minv of the star point at the time t2 corresponding to the minimum difference between the column coordinates,
if the following conditions are satisfied:
idx_minu＝idx_minv＝j
min_deltau≤Thr_u
min_deltav≤Thr_v
j is 1,2, …, Nstar2, Nstar2 is the total number of star points in the star map at time t 2;
thr _ u and Thr _ v are respectively a difference error threshold value of column coordinates and a difference error threshold value of row coordinates;
considering that i and j are the same star, and the number of the corresponding matched stars Nmatch +1, where the initial value of Nmatch is 0;
(4.4) repeating steps (4.2) - (4.3) and traversing all star points in the star map at the time t 1.
In the step (4.1), the step of,
delta_u12＝((u2a-u1d)+(u2b-u1e)+(u2c-u1f))/3
delta_v12＝((v2a-v1d)+(v2b-v1e)+(v2c-v1f))/3。
in the step (4.2), the step of,
u3i＝u1i+delta_u12
v3i＝v1i+delta_v12。
in the step (5), the method for calculating the average value of the angular velocity by using the position coordinates of the same star point in the star map at the time t1 and the star map at the time t2 is as follows:
calculating a mean value mean _ deltatau and a mean value mean _ deltav of row coordinate variations and a mean value mean _ deltav of column coordinate variations of the same star point in the star map at the time t1 and the star map at the time t2, and calculating an average value of angular velocity according to the product instantaneous field of view IFOV and the time interval deltat of two frames of images by using the following formula:
ωu＝mean_deltav*IFOV/deltat
ωv＝mean_deltau*IFOV/deltat
ωucomponent of angular velocity in the planet direction, ωvIs the component of angular velocity in the direction of the asterisk column.
deltat＝t2-t1。
In the step (7), the correction formula is as follows:
wherein (u ', v') is the corrected observed star position, (u, v) is the corrected observed star position, v0As exposure centre line coordinate, omegauComponent of angular velocity in the planet direction, ωvComponent of angular velocity in the direction of the star-row, TdIFOV is the instantaneous field of view size for the line exposure time interval.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a method for calculating angular velocity of a rolling shutter exposure star sensor in an all-day capture mode, which comprises the steps of utilizing the change rule of the positions of the same star points in different frames of star images without rolling shutter correction to match and confirm the same star points in different frames, and utilizing the position coordinates of the same star points in the different frames of star images to calculate the angular velocity; the angular velocity calculation method is applied to rolling shutter correction in a capture mode, effectively solves the problem of all-day autonomous capture of the rolling shutter exposure star sensor under the high dynamic condition, improves the dynamic performance of the product, is applicable to all rolling shutter exposure star sensors, and has good engineering application value.
Drawings
FIG. 1 is a flow chart of star point matching;
fig. 2 is a flowchart of angular velocity calculation.
Detailed Description
The invention is further elucidated with reference to the drawing.
The invention provides a high-dynamic rapid autonomous capturing method for a rolling shutter exposure star sensor, wherein the star sensor adopts a rolling shutter exposure mode to improve the dynamic performance and the updating rate of a product.
As shown in fig. 1 and fig. 2, the implementation steps of the high-dynamic fast autonomous capturing method for the rolling shutter exposure star sensor provided by the present invention are as follows:
for convenience of illustration, if the star point coordinate array at time t1 is uv _ info1, corresponding to the number of stars is Nstar1, the star point coordinate array at time t2 is uv _ info2, corresponding to the number of stars is Nstar2, and t2 > t 1:
1) if t2-t1 is less than Thr _ deltat, selecting a star map at the t1 moment and a star map at the t2 moment, and executing the step 2 in sequence, otherwise, executing the step 18);
wherein Thr _ deltat is a time difference threshold, and needs to be set according to the size of the product view field and the applicable angular speed, and the number of the same star points in the two frames of star maps needs to be ensured to be more than 3 in principle.
2) If the star point numbers Nstar1 and Nstar2 corresponding to the two frames of star maps are both larger than the set star number threshold, executing the next step in sequence, otherwise, executing the step 18);
3) calculating the distance dist _ ik between each two star points, the difference deltatau _ ik of row coordinates and the difference deltav _ ik of column coordinates by using the coordinate information uv _ info1 of the star points of the star map at the time t 1;
wherein dist _ ik is the distance between the ith star point and the kth star point in the star map at the time t1, deltatau _ ik is the difference between the row coordinates of the ith star point and the kth star point in the star map at the time t1, deltav _ ik is the difference between the row coordinates of the ith star point and the kth star point in the star map at the time t1, and the calculation formula is as follows:
deltau_ik＝ui-uk
deltav_ik＝vi-vk
u in the above formulai、viAre respectively the row coordinate, the column coordinate, u of the ith star pointk、vkRespectively the line coordinate and the column coordinate of the kth star point.
4) Calculating the distance dist _ ik between each two star points, the difference deltatau _ ik of row coordinates and the difference deltav _ ik of column coordinates by the same method as the step 3) according to the coordinate information uv _ info2 of the star points of the star map at the time t 2;
5) and selecting three star points a, b and c from the star point queue at the time t2 to form a star point triangle. To exhaust all possibilities, the triangles are composed by traversing the stars using a triple loop. The traversal order of the star point triangle in the triple loop is shown in the following table:
TABLE 1 Star point triangle traversal sequence
For each set of asterisks a, b and c, the coordinates of the asterisk are (u 2)a,v2a)、(u2b,v2b)、
(u2c,v2c) The corresponding distances are dist2 respectivelyab，dist2bc，dist3ac
6) Taking the first edge dist2 of the star point triangleabAnd traversing the star point distance queue at the time t1 in the step 3. Two points taken from the star distance queue at time t1Star (m, n) with coordinates of corresponding star point as (u 1)m,v1m)、(u1n,v1n) Distance dist1mn. If the following conditions are satisfied:
dist1mn-dist2ab≤Thr_dist
||u1m-u1n|-|u2a-u2b||≤Thr_u
||v1m-v1n|-|v2a-v2b||≤Thr_v
then (m, n) is added to match queue 1.
Wherein, Thr _ dist, Thr _ u and Thr _ v are respectively distance error threshold, difference error threshold of row coordinate and difference error threshold of column coordinate, each error threshold needs to be set according to the star point position error of specific product, and the default values are respectively 5 pixels, 3 pixels and 3 pixels.
7) And traversing the second edge (b, c) and the third edge (a, c) of the star point triangle according to the step 6, and adding the observation star pairs meeting the conditions into the matching queue 2 and the matching queue 3 respectively.
8) Searching all star point triangles successfully matched from the three matching queues according to a triangle matching method;
9) if the triangle matching is successful, executing steps 10) to 13) on each triangle which is successfully matched, or executing step 18);
10) recording coordinates of three star points a, b and c of a triangle successfully matched at the time of t2 as (u 2)a,v2a)、(u2b,v2b)、(u2c,v2c) The coordinates of the centroid of three stars d, e, f corresponding to t1 are (u 1)d,v1d)、(u1e,v1e)、(u1f,v1f). Calculating the coordinate variation of the star points of two adjacent frames, wherein the formula is as follows:
delta_u12＝((u2a-u1d)+(u2b-u1e)+(u2c-u1f))/3
delta_v12＝((v2a-v1d)+(v2b-v1e)+(v2c-v1f))/3
11) using calculated starsThe position variation and the coordinates of the star point at the time t1 forecast the theoretical position of the star point at the time t1 at the time t2 (u 3)i,v3i)
u3i＝u1i+delta_u12
v3i＝v1i+delta_v12
Wherein i is 1, …, Nstar 1.
12) For the ith star point at the time t1, calculating the difference between the theoretical position of the ith star point at the time t2 and the row coordinate of the Nstar2 point at the time t2, selecting the minimum value min _ deltau of the difference between the row coordinates and the serial number idx _ minu of the star point at the time t2 corresponding to the minimum difference between the row coordinates, calculating the difference between the theoretical position of the ith star point at the time t2 and the column coordinate of the Nstar2 point at the time t 3578, selecting the minimum value min _ deltav of the difference between the column coordinates and the serial number idx _ minv of the star point at the time t2 corresponding to the minimum difference between the column coordinates,
if the following conditions are satisfied:
idx_minu＝idx_minv＝j
min_deltau≤Thr_u
min_deltav≤Thr_v
j is 1,2, …, Nstar2, Nstar2 is the total number of star points in the star map at time t 2;
thr _ u and Thr _ v are respectively a difference error threshold value of column coordinates and a difference error threshold value of row coordinates;
considering that i and j are the same star, and the number of the corresponding matched stars Nmatch +1, where the initial value of Nmatch is 0;
13) if the number of matched stars Nmatch >3, setting a matching success flag to be 1, and executing steps 15) -17), otherwise, executing step 14) in sequence;
14) judging whether all star point triangles delta abc are traversed or not, if so, setting a matching failure mark, resetting the number of matched stars and executing the step 18); otherwise, executing the step 5), and selecting the next triangle delta abc;
15) if the matching success flag is equal to 1, calculating the mean value mean _ deltatau of the line coordinate variation and the mean value mean _ deltav of the column coordinate variation of all the matched star points, calculating the angular velocity of the product in the line direction and the column direction according to the instantaneous field of view IFOV of the product and the time interval deltat of the two frames of images, and otherwise, executing the step 18), wherein the angular velocity calculation formula is as follows:
ωu＝mean_deltav*IFOV/deltat
ωv＝mean_deltau*IFOV/deltat
16) and (3) carrying out rolling correction on the coordinates of the star point at the time t2 by using the calculated angular velocity, wherein the correction formula is as follows:
wherein (u ', v') is the corrected observed star position, v0As exposure centre line coordinate, omegauComponent of angular velocity in the planet direction, ωvComponent of angular velocity in the direction of the star-row, TdIFOV is the instantaneous field of view size for the line exposure time interval.
17) Performing all-day autonomous star map matching identification and attitude calculation by using the corrected star points;
18) and recording the star map time and star point information at the time t2 for the angular velocity calculation of the next all-day capture mode.
The method of the invention matches the coordinates of the star points in different star maps of different frames in the all-day capture mode, calculates the angular speed of the product by using the position coordinates of the same star points in different star maps of different frames, carries out rolling correction on the coordinates of the star points of the current frame according to the angular speed, and carries out all-day star map identification and attitude calculation by using the corrected coordinates of the star points. The method enables the star sensor to solve the angular velocity and perform roller shutter correction in the all-day capture mode, and effectively solves the all-day autonomous capture problem under the high dynamic condition of the roller shutter exposure star sensor.
Those skilled in the art will appreciate that the details not described in the present specification are well known.
Claims (10)
1. A high-dynamic rapid autonomous capturing method of a rolling shutter exposure star sensor is characterized by comprising the following steps:
(1) selecting two star maps, wherein the observation time of the first star map is t1, the observation time of the second star map is t2, and the time difference threshold is set between t2 and t 1;
(2) in each star map, calculating the difference of the row coordinates, the difference of the column coordinates and the distance between every two star points;
(3) selecting three star points from the star map at the time t2 to form a star triangle according to a set difference error threshold of the row coordinates, a set difference error threshold of the column coordinates and a set distance error threshold, and selecting the star point triangle matched with the star point triangle from the star map at the time t 1;
(4) taking the star points of the successfully matched star point triangle in the two frames of star maps as a reference, and performing matching confirmation on the remaining star points;
(5) judging whether the number of matched stars is greater than 3, if so, selecting all star points successfully matched and confirmed in the two frames of star maps, calculating an angular speed average value by using the position coordinates of the same star points, and entering the step (7); otherwise, judging whether all star point triangles in the star map at the time of t2 have been traversed, if not, entering the step (6), if all star point triangles in the star map at the time of t2 have been traversed, ending, resetting the matched star number, and recording the time and star point information of the star map at the time of t2 for the next autonomous capture;
(6) continuing to search for a matched star point triangle in the star map at the time t1 and the star map at the time t2, and repeating the steps (4) to (5);
(7) performing rolling correction on the positions of all star points of the current frame by using the angular velocity average value, and entering the step (8);
(8) and performing all-day autonomous star map recognition and attitude calculation by using the corrected star point coordinates to realize rapid autonomous capture.
2. The method for high-dynamic and fast autonomous capturing of a rolling shutter exposure star sensor according to claim 1, wherein the step (3) is implemented as follows:
(3.1) selecting three star points a, b and c from the star map at the time t2 to form a star point triangle abc, and recording the coordinate of the star point a as (u 2)a,v2a) The coordinate of the star point b is (u 2)b,v2b) The coordinate of the star point c is (u 2)c,v2c) Distance between star point a and star point b is dist2abDistance between star point b and star point c is dist2bcDistance between star point a and star point c is dist3ac；
(3.2) taking a first side ab of the star point triangle, selecting a group of observation star pairs from the star map at the time t1, wherein the observation star pairs comprise a star point m and a star point n, and the coordinate of the star point m is (u 1)m,v1m) The coordinate of the star point n is (u 1)n,v1n) Distance dist1 from the star points m and nmnIf the following conditions are satisfied:
dist1mn-dist2ab≤Thr_dist
||u1m-u1n|-|u2a-u2b||≤Thr_u
||v1m-v1n|-|v2a-v2b||≤Thr_v
adding the group of observation star pairs m and n into a matching queue 1;
wherein, Thr _ dist, Thr _ u and Thr _ v are respectively a distance error threshold, a difference error threshold of row coordinates and a difference error threshold of column coordinates;
(3.3) repeating the step (3.2) until all observation star pairs in the star map at the moment of t1 are traversed to obtain a matching queue 1;
(3.4) taking the second side bc of the star point triangle, and obtaining a matching queue 2 by referring to the methods in the steps (3.2) and (3.3);
taking a third edge ac of the star point triangle, and obtaining a matching queue 3 by referring to the methods in the steps (3.2) and (3.3);
and (3.5) searching all the star point triangles successfully matched with the star point triangles abc from the three matching queues.
3. The method for high-dynamic and fast self-capturing of a rolling shutter exposure star sensor according to claim 2, wherein in the step (3.5), the searching method is as follows:
and extracting a group of observation star pairs from each matching queue, wherein if the three groups of observation star pairs extracted from the three matching queues only contain three star points, a star point triangle formed by the three star points is successfully matched with a star point triangle abc.
4. The method for high-dynamic and fast automatic capturing of rolling shutter exposure star sensor according to claim 3, wherein in the step (3.2),
5. the method for high-dynamic and fast autonomous capturing of a rolling shutter exposure star sensor according to claim 1, wherein the step (4) is implemented as follows:
(4.1) let the star point triangle def in the star map at the time t1 match with the star point triangle abc in the star map at the time t2, and the three coordinates of the star point triangle abc are respectively (u 2)a,v2a)、(u2b,v2b)、(u2c,v2c) The three coordinates of the star point triangle def are respectively (u 1)d,v1d)、(u1e,v1e)、(u1f,v1f) Accordingly, the row coordinate variation delta _ u12 and the column coordinate variation delta _ v12 of two adjacent frames are calculated;
(4.2) forecasting theoretical position of ith star point at the time t1 at the time t2 (u 3) by using the calculated row coordinate variation, column left variation and star point coordinate at the time t1 of the star pointi,v3i)；
(4.3) for the ith star point at the time t1, calculating the difference between the theoretical position of the ith star point at the time t2 and the row coordinate of the Nstar2 star point at the time t2, selecting the minimum value min _ deltau of the difference between the row coordinates and the serial number idx _ minu of the star point at the time t2 corresponding to the minimum difference between the row coordinates, calculating the difference between the theoretical position of the ith star point at the time t2 and the column coordinate of the Nstar2 star point at the time t 3578, selecting the minimum value min _ deltav of the difference between the column coordinates and the serial number idx _ minv of the star point at the time t2 corresponding to the minimum difference between the column coordinates,
if the following conditions are satisfied:
idx_minu＝idx_minv＝j
min_deltau≤Thr_u
min_deltav≤Thr_v
j is 1,2, …, Nstar2, Nstar2 is the total number of star points in the star map at time t 2;
thr _ u and Thr _ v are respectively a difference error threshold value of column coordinates and a difference error threshold value of row coordinates;
considering that i and j are the same star, and the number of the corresponding matched stars Nmatch +1, where the initial value of Nmatch is 0;
(4.4) repeating steps (4.2) - (4.3) and traversing all star points in the star map at the time t 1.
6. The method for high-dynamic and fast automatic acquisition of the rolling shutter exposure star sensor according to claim 5, wherein in the step (4.1),
delta_u12＝((u2a-u1d)+(u2b-u1e)+(u2c-u1f))/3
delta_v12＝((v2a-v1d)+(v2b-v1e)+(v2c-v1f))/3。
7. the method for high-dynamic and fast automatic acquisition of the rolling shutter exposure star sensor according to claim 6, wherein in the step (4.2),
u3i＝u1i+delta_u12
v3i＝v1i+delta_v12。
8. the method for high-dynamic and fast automatic capturing of a rolling shutter exposure star sensor as claimed in claim 1, wherein in the step (5), the method for calculating the average value of angular velocities by using the position coordinates of the same star point in the star map at the time t1 and the star map at the time t2 is as follows:
calculating a mean value mean _ deltatau and a mean value mean _ deltav of row coordinate variations and a mean value mean _ deltav of column coordinate variations of the same star point in the star map at the time t1 and the star map at the time t2, and calculating an average value of angular velocity according to the product instantaneous field of view IFOV and the time interval deltat of two frames of images by using the following formula:
ωu＝mean_deltav*IFOV/deltat
ωv＝mean_deltau*IFOV/deltat
ωucomponent of angular velocity in the planet direction, ωvIs the component of angular velocity in the direction of the asterisk column.
9. The method for high-dynamic and fast automatic acquisition of the rolling-screen exposure star sensor as claimed in claim 1, wherein deltat is t2-t 1.
10. The method for high-dynamic and fast autonomous capturing of a rolling shutter exposure star sensor according to claim 1, wherein in the step (7), the correction formula is as follows:
wherein (u ', v') is the corrected observed star position, (u, v) is the corrected observed star position, v0As exposure centre line coordinate, omegauComponent of angular velocity in the planet direction, ωvComponent of angular velocity in the direction of the star-row, TdIFOV is the instantaneous field of view size for the line exposure time interval.
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