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CN-122015811-A - Near space vehicle starlight guidance, optical axis maneuver and intersection positioning method based on starlight refraction distribution model

CN122015811ACN 122015811 ACN122015811 ACN 122015811ACN-122015811-A

Abstract

The invention provides a method for refractive star light guidance, optical axis maneuver and intersection positioning of a near space vehicle. Firstly, a starlight path differential equation in the near space is deduced, and then a starlight refraction distribution model under a refraction starlight coordinate system is established by utilizing a numerical integration method. On the basis, the selected optimal refraction observation interval and the altitude of the aircraft are used for determining the nadir distance pointed by the optimal optical axis of the star sensor as a guidance law, the attitude angle and the optical axis transverse rotation angle are used for deducing the optical axis longitudinal rotation angle as an optical axis maneuvering control instruction, and the positioning is realized by using four methods respectively, namely, the intersection point of a single refraction star equal-folded ray and an equal-altitude line, the intersection point of two refraction star refraction surface normal vector cross vectors and an equal-folded ray, the intersection point of the geocentric vector of the inscribed circle center of a spherical triangle intercepted by the celestial sphere surface and the equal-folded ray of three refraction star refraction surfaces and the intersection point of a feature vector corresponding to the minimum feature value of at least three refraction star refraction surface normal vector construction matrixes.

Inventors

  • GAO ZIQIAN
  • WANG HAIYONG
  • WANG WEIHONG

Assignees

  • 北京航空航天大学

Dates

Publication Date
20260512
Application Date
20260302

Claims (6)

  1. 1. A star light guidance method for determining an optimal optical axis orientation based on a star light refraction distribution model in a near space, the method comprising the steps of: Step 1, selecting an optimal expected refraction angle range (R min , R max ) as an optimal refraction observation interval in a starlight refraction distribution model according to flight task requirements based on the existing starlight refraction distribution model in the adjacent space; Step 2, obtaining position coordinates R r (h, R max ) and R r (h, R min ) of intersection points of equal altitude lines corresponding to the aircraft under different altitudes h and equal refraction lines corresponding to an upper boundary R max and a lower boundary R min of a refraction angle of an optimal refraction observation interval under a refraction starlight coordinate system F r by an analytic geometry method; and 3) calculating the nadir distances beta s (h, R max ) and beta s (h, R min ) of the two points relative to the true direction of the reference star respectively, wherein the nadir distance pointed by the optimal optical axis is beta * S (h) = [β s (h, R max ) + β s (h, R min ) ]/2, namely the star guidance law pointed by the optimal optical axis.
  2. 2. A star sensor optical axis maneuvering method for realizing refraction positioning based on a star light refraction distribution model in a near space is characterized by comprising the following steps: Step 1, acquiring a pitch angle theta and a roll angle gamma of an aircraft relative to a geographic coordinate system F n by using an attitude sensor or a navigation computer, and simultaneously measuring a transverse rotation angle mu of an optical axis of a positioning star sensor relative to an aircraft body coordinate system F b ; step 2, deriving and obtaining a longitudinal rotation angle v of the star sensor optical axis relative to the aircraft body coordinate system based on the star light guidance method established in claim 1, wherein the formula is as follows (Wherein , ) The control command of the longitudinal movement of the optical axis is obtained.
  3. 3. A single refraction star intersection positioning method based on an isofolding ray model and an isoaltitude line model is characterized by comprising the following steps: Step 1, observing and identifying a non-refracting star by a posture-determining star sensor with an optical axis pointing to the vicinity of the zenith, and obtaining the absolute posture of an aircraft relative to a geocentric inertial coordinate system F i ; step 2, obtaining the current altitude h of the aircraft through a height sensor or a navigation computer; Step 3, based on the star light guidance method established in claim 1 and the star sensor optical axis maneuvering method established in claim 2, ensuring that the positioning star sensor meets the optimal optical axis direction, obtaining the optimal refraction star and identifying; Step 4, calculating the refraction direction star image point and the incidence direction mapping point of the optimal refraction star light on the imaging array according to the conversion relation between the absolute gesture and other coordinate systems obtained in the step 1, and obtaining a refraction star light coordinate system F r and a refraction angle R of the optimal refraction star light; And 5, determining a position coordinate R r (h, R) of an intersection point of the h equal altitude line and the R equal refraction line under the F r based on an existing starlight refraction distribution model in the adjacent space, and performing coordinate conversion and resolving to realize navigation and positioning of the aircraft.
  4. 4. The birefringent star-cross vector intersection positioning method based on the isofolding ray model is characterized by comprising the following steps of: Step 1, observing and identifying a non-refracting star by a gesture-determining star sensor with an optical axis pointing to the vicinity of the zenith, and obtaining the absolute gesture of an aircraft relative to F i ; Step 2, based on the star light guidance method established in claim 1 and the star sensor optical axis maneuvering method established in claim 2, ensuring that at least 2 positioning star sensors meet the optimal optical axis direction, obtaining at least 2 optimal refraction stars, and screening and identifying 2 maximum angular distances; Step 3, according to the conversion relation between the absolute gesture and other coordinate systems obtained in the step 1, respectively calculating the refraction direction star image points and incidence direction mapping points of 2 best refraction star lights on respective imaging arrays to obtain a refraction star light coordinate system F r1 、F r2 and a refraction angle R 1 、R 2 ; Step 4, uniformly converting the normal vectors Z 1 、Z 2 of the refraction surfaces of the two to F i for cross multiplication operation to obtain a zenith or zenith direction vector p i of the current aircraft position, and then respectively converting the zenith or zenith direction vector p i to F r1 、F r2 ; And 5, respectively determining a position coordinate R r1 of an intersection point of p r1 and R 1 and other folding rays under F r1 and a position coordinate R r2 of an intersection point of p r2 and R 2 and other folding rays under F r2 based on an existing starlight refraction distribution model in a near space, and performing coordinate transformation and calculation to perform information fusion to realize navigation positioning of the aircraft.
  5. 5. The method for positioning the intersection of the vectors of the centers of earth and the centers of three-refraction star inscribed on the basis of the isofolding ray model is characterized by comprising the following steps: Step 1, observing and identifying a non-refracting star by a gesture-determining star sensor with an optical axis pointing to the vicinity of the zenith, and obtaining the absolute gesture of an aircraft relative to F i ; Step 2, ensuring that 3 positioning star sensors meet the optimal optical axis direction, and simultaneously obtaining and identifying the optimal refraction star based on the star light guidance method established in claim 1 and the star sensor optical axis maneuvering method established in claim 2; step 3, respectively calculating refraction direction star image points and incidence direction mapping points of 3 best refraction star lights on respective imaging arrays according to the conversion relations between the absolute postures and other coordinate systems obtained in the step 1, and obtaining a refraction star light coordinate system F r1 、F r2 、F r3 and a refraction angle R 1 、R 2 、R 3 ; Step 4, calculating celestial coordinates of the circle centers of inscribed circles of spherical triangles, which are intercepted on the celestial surface, of the refraction planes corresponding to the three, unitizing geocentric vectors of the celestial coordinates as zenith or nadir direction unit vectors p i of the current aircraft position, and then respectively converting the geocentric vectors into F r1 、F r2 、F r3 ; And 5, respectively determining the position coordinates R r1 、r r2 、r r3 of the intersection points of the projections of p r1 、p r2 、p r3 on the respective refraction surfaces and the refraction rays of R 1 、R 2 、R 3 and the like under F r1 、F r2 、F r3 based on the starlight refraction distribution model in the existing near space, and performing information fusion through coordinate conversion and calculation to realize navigation positioning of the aircraft.
  6. 6. The multi-refraction star feature vector intersection positioning method based on the isofolding ray model is characterized by comprising the following steps of: Step 1, observing and identifying a non-refracting star by a gesture-determining star sensor with an optical axis pointing to the vicinity of the zenith, and obtaining the absolute gesture of an aircraft relative to F i ; Step 2, ensuring that 3 positioning star sensors meet the optimal optical axis direction, and simultaneously obtaining and identifying the optimal refraction star based on the star light guidance method established in claim 1 and the star sensor optical axis maneuvering method established in claim 2; Step 3, according to the conversion relation between the absolute gesture and other coordinate systems obtained in the step 1, respectively calculating the refraction direction star image point and the incidence direction mapping point of n (n is more than or equal to 3) optimal refraction star lights on respective imaging arrays, and obtaining a refraction star light coordinate system F r1 、F r2 、F r3 …F rn and a refraction angle R 1 、R 2 、R 3 …R n ; Step 4, uniformly converting all normal vectors Z 1 、Z 2 、Z 3 …Z n of the refraction surface into F i and constructing a matrix Calculating a unit feature vector corresponding to the minimum feature value as a zenith or zenith direction unit vector p i of the current aircraft position, and then respectively converting to F r1 、F r2 、F r3 …F rn ; And 5, respectively determining the position coordinates R r1 、r r2 、r r3 …r rn of the intersection points of the projections of p r1 、p r2 、p r3 …p rn on the respective refraction surfaces and the refraction rays of R 1 、R 2 、R 3 …R n and the like under F r1 、F r2 、F r3 …F rn based on the starlight refraction distribution model in the existing near space, and performing information fusion through coordinate conversion and calculation to realize navigation positioning of the aircraft.

Description

Near space vehicle starlight guidance, optical axis maneuver and intersection positioning method based on starlight refraction distribution model Technical Field The invention provides a star light guidance method, an optical axis maneuvering method and four intersection positioning methods for the optimal optical axis pointing of a star sensor based on a refraction rule and a refraction distribution model of star light observed by a near space vehicle, and belongs to the technical field of navigation guidance and control. Background The traditional indirect sensitive horizon method is oriented to an atmospheric external spacecraft, utilizes a star sensor arranged on the atmospheric external spacecraft to observe starlight penetrating out of an atmospheric layer after refraction, and realizes autonomous starlight navigation and positioning by simultaneously solving an empirical formula of refraction apparent height relative to refraction angle R and an analytic geometric formula of carrier position through an atmospheric refraction model and an error compensation method. However, for the near space vehicle, the observation site is still in the atmosphere, the fitting relation between the refraction apparent height and the refraction angle established previously is not suitable any more, the differential equation of the star light path position coordinates is deduced again by utilizing the Snell theorem and the Gladstone-Dale theorem, and then the coordinates and the refraction angle of each point in the refraction light path under the refraction star light coordinate system F r are determined by a numerical integration method, so that a star light refraction distribution model facing the near space vehicle is established. On the basis, the research on the refractive star light guidance and positioning method of the near space vehicle can overcome the application limitation that the traditional indirect sensitive horizon method is only suitable for the atmospheric layer external spacecraft, and expand the application field of the indirect sensitive horizon astronomical navigation technology to the near space. Disclosure of Invention The invention aims to establish a method for positioning starlight guidance, optical axis maneuver and intersection of a near space vehicle by utilizing a starlight refraction distribution model, and the invention is realized by the following technical scheme: (1) And determining the intersection point of the corresponding equal altitude line under the altitude h and the equal refraction line corresponding to the refraction angle upper boundary R max and the refraction angle lower boundary R min of the optimal refraction observation interval based on a starlight refraction distribution model (shown in figure 1), and calculating the nadir distances beta s(h, Rmax) and beta s(h, Rmin of the two points relative to the true direction of the reference star), thereby obtaining the nadir distance pointed by the optimal optical axis, namely the starlight guidance law pointed by the optimal optical axis. (2) The longitudinal rotation angle v j of the optical axis relative to F b is deduced from the pitch angle θ and the roll angle γ of the aircraft relative to the geographic coordinate system F n and the transverse rotation angle mu j of the optical axis (unit vector of the sensor is S j, j=1, 2, 3) of the positioning star sensor relative to the aircraft body coordinate system F b, and the longitudinal maneuver control command of the optical axis is obtained. For a dynamic, plane symmetrical structure near space vehicle (wave multiplier for example) and a static, rotation symmetrical structure near space vehicle (aerostat for example), the installation mode of the distributed star sensor is shown in fig. 2 and 3 respectively. (3) For the situation that only a single optimal refraction star is observed, F r and R of the star are determined through a refraction direction star image point and an incidence direction mapping point of starlight on an imaging array, the current altitude h of the combined aircraft is determined, and an intersection point R r (h, R) of an h equal altitude line and an R equal refraction line in a starlight refraction distribution model is taken as the position of the current aircraft. (4) For the situation that two optimal refraction stars can be observed, F r1、Fr2 and R 1、R2 of the star light are determined through refraction direction star image points and incidence direction mapping points of the star light on respective imaging arrays, normal vectors of refraction planes of the star light and the incident direction mapping points are subjected to cross multiplication operation, then intersection points of the cross multiplication vectors and folding rays such as R 1 or R 2 in respective star light refraction distribution models are respectively obtained, and information fusion is carried out to obtain the positions of the current aircraft. (5) For the situation