Long baselines laser ranging realizes without reference mark satellite Precise Position System and methodTechnical field
The present invention relates to satellite remote sensing technology, particularly, relate to a kind of Long baselines laser ranging and realize without reference mark satellite Precise Position System and method.
Background technology
The information that satellite remote sensing technology obtains can be divided three classes: qualitative, location and quantitatively.In above-mentioned three category informations, " location " information directly reflects the spatial correspondence between sensor information and target, is the important prerequisite of remote sensing qualitative and quantitative analysis and basis.At present, external satellite is having under the condition of reference mark, and positioning for ground precision can reach a meter magnitude, can reach the magnitude of ten meters, hundred meters without positioning for ground precision during reference mark, and domsat positioning for ground level and the U.S., France, Japan etc. also have larger gap.
In the world today, under-developed area about 90% belongs to Wu Tuqu, Pillarless caving satellite positioning for ground precision depends on LOS point precision to a great extent, and LOS point precision is determined with satellite orbital position, flight attitude is determined, in the thermal deformation of structure and mechanism and satellite flight process unpredictable shake be associated.Be subject to the development restriction such as Current hardware, technique, revise optical axis sensing deviation by means of only the orbit determination, accuracy of attitude determination etc. of improving satellite platform and be difficult to meet the requirement of high precision positioning for ground.
Summary of the invention
For defect of the prior art, in order to improve satellite positioning for ground precision, promote the field development of high precision satellite surveying and mapping, photography etc., the present invention is based on the advantage of laser radar precision ranging, propose a kind of Long baselines laser ranging and realize without reference mark satellite accurate positioning method.
A kind of Long baselines laser ranging provided according to an aspect of the present invention realizes without reference mark satellite Precise Position System, comprises satellite platform, catoptron and laser radar; Described laser radar and described catoptron are all arranged on described satellite platform.
Preferably, described satellite platform comprises satellite platform body, head rod and the second connecting link; One end and one end of described second connecting link of described head rod are connected the both sides of described satellite platform body respectively.
Preferably, described laser radar comprises generating laser, the first laser signal receivers, the second laser signal receivers and the 3rd laser signal receivers; Described generating laser is arranged in described satellite platform body, and the laser pulse of described laser transmitter projects reflects earthward by catoptron; Described first laser signal receivers, the second laser signal receivers are separately positioned on the other end of described head rod and the other end of described second connecting link; Described 3rd laser signal receivers is arranged on described satellite platform body; The receive direction of described first laser signal receivers, described second laser signal receivers and described 3rd laser signal receivers all points to ground.
Preferably, described catoptron adopts electric drive rotatable mirror.
Preferably, described generating laser adopts Nd:YAG solid state laser, can launch 1064nm and 532nm two kinds of wavelength.
Preferably, described head rod and the second connecting link employing length are the rigid rod of 1 meter to 100 meters.
The Long baselines laser ranging provided according to another aspect of the present invention realizes the satellite accurate positioning method without reference mark satellite Precise Position System, comprises the steps:
Step 1: by generating laser to ground or low-altitude detection objective emission laser pulse, and record t launch time simultaneously0;
Step 2: the first laser signal receivers D1, the second laser signal receivers D2and the 3rd laser signal receivers D3receive the laser signal returned from ground return point P respectively, and record receives the time t of signal respectively1, t2, t3;
Step 3: calculate the first laser signal receivers D respectively1, the second laser signal receivers D2and the 3rd laser signal receivers D3to the distance r of ground return point1, r2and r3;
Step 4: the position coordinates being obtained Laser emission moment satellite by the Big Dipper or GPS location, according to the installation matrix of three laser signal receivers, calculates the position coordinates D of three laser signal receivers in the Laser emission moment1(x1, y1, z1), D2(x2, y2, z2), D3(x3, y3, z3);
Step 5: by position coordinates D1(x1, y1, z1), D2(x2, y2, z2), D3(x3, y3, z3) and r1, r2, r3substitute into system of equations, the three-dimensional coordinate P (x, y, z) of ground return point can be obtained.
Preferably, described step 3 adoptscalculate r1, r2and r3, wherein c is the light velocity, rifor laser signal receivers is to the distance of ground return point, tifor laser signal receivers receives the time of signal, t0for laser pulse launch time.
Preferably, in described step 5, system of equations is
Compared with prior art, the present invention has following beneficial effect:
1, the present invention over the ground hi-Fix do not need the high-precision control point on traditional ground, but obtain ground " reference mark " coordinate on one's own initiative, accurately, effectively can solve the orientation problem that less-developed uncovered area does not have ground control point, and ocean, mountain forest etc. are without the orientation problem of obvious surface mark;
2, the present invention does not need accurate Satellite attitude information, the thermal deformation Accurate Calibration to satellite structure, mechanism is not relied on yet, only according to the track location information (position coordinates of satellite can reach very high precision by the positioning system such as the Big Dipper, GPS location) knowing satellite, high precision positioning for ground can be realized, greatly reduce the complicacy of requirement to related satellite hardware and system;
3, the present invention utilizes laser distance measurement method, the range information recorded by co-ordinates of satellite, laser radar can accurately resolve topocentric coordinate information, and structure is simple, and algorithm is simple and easy, the satellites such as photography, mapping, laser three-dimensional imaging can be equipped on, realize high-precision three-dimensional location over the ground;
4, the present invention can obtain the three-dimensional accuracy coordinate of localizing objects point, the hi-Fix of satellite to low latitude moving target can be realized, obtain the three-dimensional coordinate information of low flyer (as guided missile, aircraft) etc., speed, the orbit information of target can also be obtained under Continuous Tracking pattern, there is great application value.
Accompanying drawing explanation
By reading the detailed description done non-limiting example with reference to the following drawings, other features, objects and advantages of the present invention will become more obvious:
Fig. 1 is the structural representation that medium-long baselines laser ranging of the present invention realizes without reference mark satellite Precise Position System;
Fig. 2 is that medium-long baselines laser ranging of the present invention realizes without the pinpoint measuring principle figure of reference mark satellite.
In figure:
1 is satellite platform body;
2 is generating laser;
3 is catoptron;
4 is head rod;
5 is the second connecting link;
6 is the first laser signal receivers;
7 is the second laser signal receivers;
8 is the 3rd laser signal receivers.
Embodiment
Below in conjunction with specific embodiment, the present invention is described in detail.Following examples will contribute to those skilled in the art and understand the present invention further, but not limit the present invention in any form.It should be pointed out that to those skilled in the art, without departing from the inventive concept of the premise, some distortion and improvement can also be made.These all belong to protection scope of the present invention.
In the present embodiment, as shown in Figure 1 and Figure 2, Long baselines laser ranging provided by the invention realizes comprising satellite platform, catoptron 3 and laser radar without reference mark satellite Precise Position System.Described laser radar and described catoptron 3 are all arranged on described satellite platform.Described satellite platform comprises satellite platform body 1, head rod 4 and the second connecting link 5; One end and described second connecting link 5 one end of described head rod 4 are connected the both sides of described satellite platform body 1 respectively.Described laser radar comprises generating laser 2, first laser signal receivers 6, second laser signal receivers 7 and the 3rd laser signal receivers 8; Described generating laser 2 is arranged in described satellite platform body, and the laser pulse that described generating laser 2 is launched reflects earthward by catoptron 3; Described first laser signal receivers 6, second laser signal receivers 7 is separately positioned on the other end of described head rod 4 and described second connecting link 5 other end; Described 3rd laser signal receivers 8 is arranged on described satellite platform body 1; The receive direction of described first laser signal receivers 6, described second laser signal receivers 7 and described 3rd laser signal receivers 8 all points to ground.3rd laser signal receivers 8 is arranged on satellite platform body 1, can be total to light path and receive, also can adopt specific receiving system with main load (as optical camera etc.).Described catoptron 3 adopts electric drive rotatable mirror, to realize continuous, the quick adjustment in laser pulse light beam direction.Catoptron 3 can control the deflection in laser beam direction, realizes the location of difference over the ground in certain visual field, also can realize the localization and tracking to moving target.Described head rod 4 and the second connecting link 5 adopt length to be the rigid rod of 1 meter to 100 meters.Launch after satellite carries out trackwork, after launching and satellite platform angle fix, the length of concrete bar, can require to do specific design according to different satellite task from platform angle.
Described generating laser 2 adopts Nd:YAG solid state laser, can launch 1064nm and 532nm two kinds of wavelength.As laser three-D cartographic satellite adopts the laser of 1064nm wavelength, optical photography satellite adopts the laser of 532nm wavelength.
For the Emission Lasers of different wave length, adopt different laser detectors: 532nm wavelength chooses Si-APD detector, 1064nm selects InGaAS-APD detector.Energy of lasers is mJ magnitude, and the angle of divergence is μ rad magnitude, can adjust pulsed laser energy and the angle of divergence flexibly according to different target characteristic and object height.
Head rod 4 and the second connecting link 5 are equivalent to " Long baselines " in surveying in the present invention, and as shown in Figure 2, concrete implementation step is as follows for measuring process:
Step 1: by generating laser to ground or low-altitude detection objective emission laser pulse, and record t launch time simultaneously0;
Step 2: the first laser signal receivers D1, the second laser signal receivers D2and the 3rd laser signal receivers D3receive the laser signal returned from ground return point P respectively, and record receives the time t of signal respectively1, t2, t3;
Step 3: calculate the first laser signal receivers D respectively1, the second laser signal receivers D2and the 3rd laser signal receivers D3to the distance r of ground return point1, r2and r3, wherein:c is the light velocity, rifor laser signal receivers is to the distance of ground return point, tifor laser signal receivers receives the time of signal, t0for laser pulse launch time;
Step 4: the position coordinates being obtained Laser emission moment satellite by the Big Dipper or GPS location, according to the installation matrix of three laser signal receivers, calculates the position coordinates D of three laser signal receivers in the Laser emission moment1(x1, y1, z1), D2(x2, y2, z2), D3(x3, y3, z3);
Step 5: by position coordinates D1(x1, y1, z1), D2(x2, y2, z2), D3(x3, y3, z3) and r1, r2, r3substitute into system of equations below, the three-dimensional coordinate P (x, y, z) of ground return point can be obtained.
The present invention meets without reference mark, the requirement of high precision positioning for ground, comprise satellite platform and laser radar two parts, laser radar load is made up of a generating laser and three laser signal receivers, satellite platform body stretches out two connecting links respectively to two reverse directions, the end of every root bar installs a laser signal receivers, and the 3rd laser signal receivers is arranged on satellite platform.Method provided by the invention utilizes laser radar range principle, measures the distance of three receivers and impact point, then substitutes into the three-dimensional coordinate of three receivers under the coordinate system that is connected, and namely obtains the three-dimensional coordinate of impact point by solving equations.The present invention adopts Long baselines laser distance measurement method to realize high precision positioning for ground, calculate simple, simple structure, little to the attitude information dependence of satellite high-precision, greatly reduce the requirement to hardware such as star sensors, can be applied to photogrammetry satellite, linear array or face battle array laser three-D cartographic satellite, have on the satellites such as the optical imagery of high precision positioning for ground demand.
Above specific embodiments of the invention are described.It is to be appreciated that the present invention is not limited to above-mentioned particular implementation, those skilled in the art can make various distortion or amendment within the scope of the claims, and this does not affect flesh and blood of the present invention.