CN103033165B - Determination method for inclined angles of laser reflectors of GEO satellites under multi-observation-station condition - Google Patents

Abstract

The invention discloses a determination method for inclined angles of laser reflectors of GEO satellites under a multi-observation-station condition. The determination method comprises the steps that an optical ground center is worked out according to positions of laser observation stations on the ground; distances from the optical center on an earth surface to the laser observation stations on the ground are identical; secondary inclined angles of the laser reflectors in satellite bodies are determined according to positions of satellite orbits and the optical center on the ground; and normal lines of reflecting surfaces of the laser reflectors are allowed to point at the optical center on the ground. As for the multiple satellites, the secondary inclined angles of the laser reflectors of the satellites are worked out respectively; normalization processing of the inclined angles, review of laser incidence angles and design of inclined brackets are performed; technical states of the laser reflectors of the satellites can be unified; and volume production and interchange are facilitated.

Description

The included angle defining method of GEO laser satellite reverberator in many survey stations situation

Technical field

The present invention relates to angle mount angle design method and realization thereof that one is positioned at the GEO satellite optical observation product of different orbital position (the substar position of corresponding different geographic longitude).

Background technology

GEO satellite has been widely used in navigation, communication, broadcast, the field such as meteorological, and the determination of its orbital position is mainly determined according to the real needs of user, needs to consider the factor such as overlay area, signal frequency.In satellite navigation system, GEO satellite has extremely important status, especially for the system with regional service ability need.GEO satellite, in order to provide accurate location-based service, needs to carry out Precise Orbit and determines, and precise laser range finding is the method often adopted.By ground laser survey station Emission Lasers, and receive the laser of satellite borne laser reflector reflects, in the recording laser transmitting and receiving moment, carry out the orbit measurement of GEO satellite.

Class round platform laser reflector is the configuration that low orbit satellite often adopts, different from low orbit satellite, and in GEO class, high rail satellite all adopts the laser reflector of planar array form.The substar of GEO satellite under the line near, be arranged on GEO satellite to ground laser reflector in not tilting situation, its normal direction points to equator, and through the earth's core.Therefore, although GEO satellite considers the requirements such as overlay area when orbital position is selected, laser reflector specular cross section still can be caused to reduce.So the optical articles that GEO satellite is placed generally can carry out tilting design.

For a long time, space flight model task all carries out development for single satellite, and each design is only for the production of a satellite, and the state of the art of product is also well-determined.Along with the complexity of space mission improves constantly, rely on single satellite can not satisfy the demands, adopting many stars networking formation constellation to realize higher user's request becomes a solution.Therefore, the existing demand that cannot meet user Geng Gao according to single particular task to the tilting method for designing of optical articles that single satellite carries out.

Summary of the invention

Technology of the present invention is dealt with problems and is: overcome the deficiencies in the prior art, provide a kind of secondary included angle defining method for GEO laser satellite reverberator, significantly can reduce the incident angle of each survey station Emission Lasers relative to laser reflector, increase the specular cross section of laser reflector, to batch product unit, there is general applicability simultaneously.

Technical solution of the present invention is: the included angle defining method of GEO laser satellite reverberator in many survey stations situation, and step is as follows:

(1) according to the position of each laser survey station in ground, terrestrial optical center is calculated; Described terrestrial optical center is equal with the earth's core angle of each laser survey station;

(2) obtain the orbital position of each GEO satellite, for each GEO satellite, all carry out following identical operation:

(21) GEO laser satellite reverberator is carried out once tilting along the Y-axis of satellite body coordinate system, the ground sub-satellite track that the normal of laser reflector is pointed to enters along equatorial eastern, be summit until ground substar is in GEO satellite position, take the X-axis of satellite body coordinate system as vertical axle, on the circular conical surface that formed for bus with the line of terrestrial optical center and GEO satellite, remember that an angle of eccentricity is α _k, k=1,2 ... n, n are the number of whole GEO satellite;

(22) GEO laser satellite reverberator is carried out secondary along the X-axis of satellite body coordinate system tilting, until the ground substar pointed to of the normal of laser reflector and terrestrial optical center superposition, remember that secondary angle of eccentricity is β _k;

(3) be normalized the included angle of each GEO laser satellite reverberator, the angle making every GEO laser satellite reverberator twice tilting is respectively (α _k', β _k'), (α _k', β _k') computing formula be

$\left\{\begin{array}{c}{{\mathrm{\α}}_k}^{\′}=\frac{{\mathrm{\α}}_k}{\left|{\mathrm{\α}}_k\right|}\underset{k=1}{\overset{n}{\mathrm{\Σ}}}\left|{\mathrm{\α}}_k\right|/n\\ {{\mathrm{\β}}_k}^{\′}=\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{\β}}_k/n\end{array}\right.;$

(4) specular cross section of each GEO laser satellite reverberator is checked, judge that the laser reflector of every GEO satellite is according to (α _k', β _k') twice tilting after, whether the incident angle of the laser that each laser survey station is launched meets the demands, if met the demands, the laser reflector of every GEO satellite is according to respective (α _k', β _k') carry out tilting; If do not met, all GEO satellites do not met the demands are classified as one group, re-executing the included angle of step (3) to this group GEO laser satellite reverberator is normalized until the laser reflector of every GEO satellite is after twice tilting, the incident angle of the laser that each laser survey station is launched meets the demands, and the laser reflector of every GEO satellite carries out tilting according to the angle met the demands.

The method at described calculating terrestrial optical center is: first determine that Laser Measuring stands in the coordinate position in rectangular coordinate system respectively according to the longitude of laser survey station and latitude, then with the coordinate position of terrestrial optical center in described rectangular coordinate system for solving variable, Nonlinear System of Equations is set up so that each laser survey station is equal with the earth's core angle at terrestrial optical center, obtaining the coordinate position of terrestrial optical center in described rectangular coordinate system by solving Nonlinear System of Equations subsequently, being obtained longitude and the latitude at terrestrial optical center by coordinate transform.

The present invention's advantage is compared with prior art: the inventive method is according to the geographic longitude of multiple laser survey station and latitude, by calculating terrestrial optical center, determine the normal direction pointing direction of planar array distribution laser reflector, and calculate the tilting angle demand of required secondary, again by normalization method for designing, determine to adapt to many tilting schemes of GEO satellite, and carry out checking of laser incident angle.The sensing optimization of multi-satellite laser reflector to multiple ground survey station can be realized thus, reduce the incident angle of land station's Emission Lasers relative to laser reflector, increase reverberator specular cross section, improve the laser observations condition of multiple survey station to meet the demand of laser ranging, unified the design point of multi-satellite laser reflector simultaneously, be conducive to the production and processing of laser reflector, ensure the interchangeability of reverberator, reach the object adapting to batch product unit manufacture claim.

Accompanying drawing explanation

Fig. 1 is the FB(flow block) of the inventive method;

Fig. 2 is the concentric circles determination schematic diagram at terrestrial optical center in the inventive method;

Fig. 3 is the tilting schematic diagram of laser reflector secondary rotating in the inventive method.

Embodiment

For serving many GEO Navsats of China and neighboring area, China's territory scope is very large, according to current observation requirement, in order to realize multistation joint observation, must have the geometry distribution of good surface-based observing station.But the observation condition of part GEO satellite rail position to some laser survey station is poor, even may not meet the requirement of laser incident angle, the observation to certain laser satellite reverberator also just can not be completed.Such as, the Laser Measuring that orbital position is to the west stands in measurement geographic longitude GEO laser satellite by east reverberator may face the problems referred to above, otherwise also sets up.Same reason, GEO satellite measured by the survey station that geographic latitude is very high also can face such problem.Meanwhile, a laser reflector GEO satellite installed also will take into account the different multiple survey stations of geographical longitude and latitude.

Therefore, in order to adapt to the GEO laser satellite observation requirements of multiple rail position, reduce laser incident angle, increase specular cross section, carrying out tilting to the laser reflector that GEO satellite is installed is the method being comparatively suitable for adopting.The substar position of the corresponding different geographic longitude of different GEO satellite orbital positions.General for same GEO satellite, in order to meet the good requirement of observation geometry to same satellite, laser observations station, multiple ground may be had and observe, and take geometry to distribute the distribution of good survey station as far as possible.

GEO laser satellite reverberator is generally installed on ground, and as passive device, the laser signal launched by reflection ground survey station is completed Precise Orbit and measures task.Following scheme can be adopted to increase the specular cross section of GEO laser satellite reverberator:

According to geographic longitude and the latitude at each laser observations station, determine " terrestrial optical " center "." terrestrial optical " center " should meet the shortest principle of the spherical distance of each survey station; for three surface-based observing stations; " terrestrial optical " center " is equal to the spherical distance of each survey station, for multiple survey station, determine that " three survey stations of terrestrial optical " center " are positioned at maximum circumscribed three survey stations of all survey stations exactly; namely on the three erect-positions circle that three stations are determined on earth sphere, and " terrestrial optical " center " is the spherical geometry center of circle.See accompanying drawing 2, O ' be land station S ₁, S ₂, S ₃corresponding optical centre, three survey stations are with " the earth's core angle that terrestrial optical " center " is formed is equal.

" computing method of terrestrial optical " center " are: first determine according to the longitude and latitude of three survey stations the coordinate position that survey station is connected in equatorial system of coordinates in the earth's core respectively; set x, y, z as rectangular coordinate; θ is latitude; λ is longitude; R is earth radius, then the transformational relation of longitude and latitude and rectangular coordinate is as follows:

$\left\{\begin{array}{c}x=R\×\sin \mathrm{\θ}\cos \mathrm{\λ}\\ y=R\×\cos \mathrm{\θ}\sin \mathrm{\λ}\\ z=R\×\sin \mathrm{\θ}\end{array}\right.$

With " rectangular coordinate of terrestrial optical " center ", for solving variable, sets up the relational expression of relative the earth's core subtended angle between terrestrial optical center with each survey station respectively, and with three survey stations with " the earth's core subtended angle of terrestrial optical " center " is equal sets up Nonlinear System of Equations.Obtain by solving nonlinear equation " rectangular coordinate of terrestrial optical " center ", then obtain corresponding longitude and latitude by above-mentioned coordinate transformation relation, " terrestrial optical " center " is exactly the point be positioned on earth surface that each GEO laser satellite reverberator normal direction is pointed to.

With Keshen, Sanya and station, Beijing three, its geographical longitude and latitude sees the following form.By said method solve obtain " terrestrial optical " center " is Central China point (east longitude 96 °, north latitude 32 °), and now, the laser reflector on each star all can obtain less incident angle.

Table 1 is solved " optical centre " by three China's laser survey stations

Laser survey station	Longitude (east longitude)	Latitude (north latitude)
			Beijing	116°	40°
Keshen	75.5°	39°
			Sanya	109°	18°
Optical centre	96°	32°

Tried to achieve by said method and " after terrestrial optical " center ", point to make on star laser reflector that " terrestrial optical " center " can adopt the method for laser reflector " secondary is tilting ".

The position distribution at laser observations station is in China territory, according to the distribution situation of survey station, generally determine that " terrestrial optical " center " is in the middle part of China; point to " terrestrial optical " center " (see accompanying drawing 3) to make laser reflector on star, need to carry out once tilting (East and West direction is biased) along celestial body Y-axis, the ground substar that laser reflector normal is pointed to is by P ₀point proceeds to P along equatorial eastern ₁point, wherein P ₁point be in satellite position is summit, with satellite body X-axis for hang down axle, with " terrestrial optical " center " and satellite links be bus formed circular conical surface on, angle of eccentricity is α.Secondary tilting (being biased) is carried out northwards afterwards, until laser reflector normal points to by P along celestial body X-axis ₁point moves to that " terrestrial optical " center ", angle of eccentricity is β northwards.All obtain less laser incident angle by tilting each survey station, there is better observation effect.

Satellite body coordinate system is the rectangular coordinate system be connected with satellite body, when GEO satellite normally runs in-orbit, the initial point of satellite body coordinate system is centroid of satellite, and X-axis is satellite working direction, Z axis points to the earth's core by satellite, and Y-axis and all the other diaxons meet the right-hand rule.

For the GEO satellite of serving China, " terrestrial optical " center " is positioned in the middle part of China territory, then the inevitable north orientation of all laser reflectors is tilting, has β > 0.And due to GEO satellite along equatorial direction in the " feature that terrestrial optical " center " both sides " relatively uniform " distribute; determine satellite borne laser reverberator along the " feature that terrestrial optical " center " thing both sides are respectively tilting, namely for " western star ", α > 0 is had; For " eastern star ", there is α < 0.

For the GEO satellite of east longitude 80 °, when not tilting, laser reflector normal points to the intersection point of equator and east longitude 80 ° of warps, in order to make its point to east longitude 96 ° and north latitude 32 ° " terrestrial optical " center "; laser reflector is first along tilting 2.3 ° of star body Y-axis east; reverberator normal is pointed to and moves to east longitude 93.1 ° of positions eastwards along equator, rear reflector along star body X-axis tilting 5.2 ° again, make its normal point to terrestrial optical center.

For batch product satellite, laser reflector is as unit, and tilting support, as adopted similar designs, has identical state of the art and contributes to the management of product, is convenient to realize criticizing produce.Therefore, taking into account under the prerequisite ensureing certain specular cross section, carrying out " normalization " design, the GEO laser satellite reverberator classificationization of multiple rail position can be designed, uniform technical state.

" normalization " method for designing adopts the mentality of designing of " multi-point average, check ", and for n GEO satellite, its reverberator normal be made to point to optical centre, and each satellite twice included angle is respectively α ₁, α ₂..., α _k... α _nand β ₁, β ₂..., β _k... β _n, then included angle (the α of every laser satellite reverberator after normalization _k', β _k') be respectively:

$\left\{\begin{array}{c}{{\mathrm{\&alpha;}}_k}^{\&prime;}=\frac{{\mathrm{\&alpha;}}_k}{\left|{\mathrm{\&alpha;}}_k\right|}\underset{k=1}{\overset{n}{\mathrm{\&Sigma;}}}\left|{\mathrm{\&alpha;}}_k\right|/n\\ {{\mathrm{\&beta;}}_k}^{\&prime;}=\underset{k=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&beta;}}_k/n\end{array}\right.$

Check the incident angle of every satellite according to the tilting rear relatively each survey station laser of normalized angle, if incident angle meets the demands, then this laser satellite reverberator can design tilting support according to normalized included angle; If incident angle does not meet the demands, then using all laser reflectors do not met the demands separately as one group, by the normalization again according to the method described above of its included angle, the new normalization included angle of this group laser reflector can be obtained, so repeatedly until complete the normalization of whole laser reflector included angle and check.

The content be not described in detail in instructions of the present invention belongs to the known technology of those skilled in the art.

Claims (1)

1. the included angle defining method of GEO laser satellite reverberator in more than survey station situation, is characterized in that step is as follows:

(1) according to the position of each laser survey station in ground, terrestrial optical center is calculated; Described terrestrial optical center is equal with the earth's core angle of each laser survey station; Calculating the method at terrestrial optical center is: first determine that Laser Measuring stands in the coordinate position in rectangular coordinate system respectively according to the longitude of laser survey station and latitude, then with the coordinate position of terrestrial optical center in described rectangular coordinate system for solving variable, Nonlinear System of Equations is set up so that each laser survey station is equal with the earth's core angle at terrestrial optical center, obtaining the coordinate position of terrestrial optical center in described rectangular coordinate system by solving Nonlinear System of Equations subsequently, being obtained longitude and the latitude at terrestrial optical center by coordinate transform;

(2) obtain the orbital position of each GEO satellite, for each GEO satellite, all carry out following identical operation:

(21) GEO laser satellite reverberator is carried out once tilting along the Y-axis of satellite body coordinate system, the ground sub-satellite track that the normal of laser reflector is pointed to enters along equatorial eastern, be summit until ground substar is in GEO satellite position, take the X-axis of satellite body coordinate system as vertical axle, on the circular conical surface that formed for bus with the line of terrestrial optical center and GEO satellite, remember that an angle of eccentricity is α _k, k=1,2 ... n, n are the number of whole GEO satellite;

(22) GEO laser satellite reverberator is carried out secondary along the X-axis of satellite body coordinate system tilting, until the ground substar pointed to of the normal of laser reflector and terrestrial optical center superposition, remember that secondary angle of eccentricity is β _k;

(3) be normalized the included angle of each GEO laser satellite reverberator, the angle making every GEO laser satellite reverberator twice tilting is respectively (α _k', β _k'), (α _k', β _k') computing formula be

$\left\{\begin{array}{c}{{\mathrm{\&alpha;}}_k}^{\&prime;}=\frac{{\mathrm{\&alpha;}}_k}{\left|{\mathrm{\&alpha;}}_k\right|}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\left|{\mathrm{\&alpha;}}_i\right|/n\\ {{\mathrm{\&beta;}}_k}^{\&prime;}=\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&beta;}}_i/n\end{array}\right.;$

(4) specular cross section of each GEO laser satellite reverberator is checked, judge that the laser reflector of every GEO satellite is according to (α _k', β _k') twice tilting after, whether the incident angle of the laser that each laser survey station is launched meets the demands, if met the demands, the laser reflector of every GEO satellite is according to respective (α _k', β _k') carry out tilting; If do not met, all GEO satellites do not met the demands are classified as one group, re-executing the included angle of step (3) to this group GEO laser satellite reverberator is normalized until the laser reflector of every GEO satellite is after twice tilting, the incident angle of the laser that each laser survey station is launched meets the demands, and the laser reflector of every GEO satellite carries out tilting according to the angle met the demands.