CN103605424B - The viewpoints' integration method of space-air-ground integration situation expression engine and band inertia thereof - Google Patents

Abstract

The present invention relates to the viewpoints' integration method of space-air-ground integration situation expression engine and band inertia thereof, by setting rational damped coefficient, when input quantity stops transformation, velocity amplitude does not also have a vanishing, and corresponding viewpoint change also will continue, until speed is zero to stop transformation, this viewpoints' integration mode, inertia can be given to target in environment viewing, make Consumer's Experience be closer to truly, make the most lively.

Description

The viewpoints' integration method of space-air-ground integration situation expression engine and band inertia thereof

Technical field

The present invention relates to a kind of viewpoints' integration method of space-air-ground integration situation expression engine and band inertia thereof.

Background technology

Along with the development of technology, the activity of the mankind is no longer limited to ground, and space becomes the another important place of mankind's activity. The manor important in order to capture this block of space, increasing satellite launch goes up to the air so that reach with the satellite lost efficacy in-orbit Thousands of, spatial environments drastically deteriorates.For guaranteeing space safety, safeguarding spatial benefit, various countries establish oneself one after another Space situation awareness system.Space situation awareness system is the system engineering of a bulky complex, and its packet obtained contains How these data are effectively used by all kinds of multi-source heterogeneous data such as space-based, ground, for strategy and tactics decision-making and other Space operation provides information service to become a problem in the urgent need to address.

In order to preferably grasp the Various types of data such as the extraterrestrial target of roomage state system senses, spatial environments Changing Pattern and Interaction relationship, needs to develop space-air-ground integration situation expression engine, will arrive greatly whole solar each major planet, little To a tellurian earth station and surrounding fine resolution landform thereof, it is seen that extraterrestrial target and sightless spatial environments etc. each Class data carry out unifying to show.Realize the most smooth and easy displaying of all kinds of situation data, it is necessary first to solution is exactly viewpoint control Problem processed, the quality of viewpoints' integration directly affects user's experience to situation expression engine.

Viewpoint is the unique interface that user observes Visual Scene, is the fundamental of virtual reality.For simple visualization Scene display, the function that general exploitation instrument itself provides can meet requirement, such as the gluLookAt () letter of OpenGL Number.Complicated Visual Scene is then needed to the viewpoints' integration method more with " feeling of immersion ", as GoogleEarth, The viewpoints' integration method of the Leica Virtual Explorer systems such as WorldWind, the viewpoints' integration of this kind of visualization engine mainly solves Being the most preferably to realize ground roaming, viewpoint, all the time with the earth as focus, can carry out rotating, scaling and around ground Face point rotates, horizon level all the time during near-earth roaming, it is impossible to tilt；The a class such emphasis of such as STK is also had to exist The visualization engine of extraterrestrial target emulation, the target that user is paid close attention to by this engine is placed in the center of visual field always, carries out target Rotating and scaling, be not suitable for browsing of ground scene, viewpoint can switch between different target, but switching uses Directly mapping mode, does not has the process of conversion, the loftiest；An other class is that interplanetary visualization as such in Celestia is drawn Holding up, this kind of visualization engine viewpoint can carry out the switching of smoothness between different target, but its focus being primarily upon is All kinds of astronomical targets, when viewpoint zooms in earth isosphere surface, it may appear that horizon tilts, it is impossible to click on around sphere The problems such as row rotation, thus affect the viewing experience of ground surface or terrain.A few class viewpoints' integration methods above all cannot well expire The demand of foot space-air-ground integration situation expression engine.

Due to the main feature of space-air-ground integration situation expression engine have that data type is many, space scale and distance change is big, Relate to the features such as coordinate system is many, express to enable the viewpoints' integration method of design preferably to adapt to space-air-ground integration situation, Each main feature expressed space-air-ground integration situation below carries out detailed analysis.

1.1 data types are many

Space situation awareness data are the expression objects of space-air-ground integration situation expression engine, and space situation awareness data are numerous and complicated Complicated.According to the type of Monitoring Data, perception data can be divided into two big classes, and one is extraterrestrial target data, including Earth's orbit On all targets: all kinds of big Small object such as moving satellite, inert satellite, space junk in-orbit；Two is spatial environments data, The Various types of data such as including solar activity related data, earth's magnetic field, ionosphere, space radiation band, high energy particle.Except perception Outside data, also class data are the data of space situation awareness system itself, as ground and space-based monitoring system itself are distributed feelings Condition, running status etc., this kind of data can be classified as a class with extraterrestrial target data from expression-form.Other class data are The geographic information data of the earth itself and whole solar each major planet data and star background data.Thus constitute one The basic data of the individual complete situation expression system comprising the sky world, in the above data, part data itself are visible Intuitively, such as data such as extraterrestrial targets, these data to reproduce really, and part data itself are abstract sightless, It is thus desirable to these data are carried out Visualization, make sightless to become visible.The most various data need same Carrying out under one framework unifying to show, this brings unprecedented difficulty for viewpoints' integration.Fig. 1 is space-air-ground integration state Gesture expresses the nomogram of engine.

1.2 space scales and distance change are big

Space-air-ground integration situation expression engine except data type how in addition to, also an important feature needs to express Object space yardstick and distance change are huge, greatly to the maximum target sun that radius in the whole solar system is 696,300 kms, Little to several meters of big police radars on earth surface；As far as Neptune farthest apart from the sun from the sun 4,504,300,000 Km, also has 57,910,000 kms to Mercury that the sun is nearest, and the distance between ground two targets then can be near Within one meter, how to realize the Precise Representation of target under large scale span, and seamless between target under big distance Switching is the key technology that must solve.

1.3 to relate to coordinate system many

All kinds of targets in space-air-ground integration situation expression engine are not simple superpositions, but according to strict time-space relationship Model, allows target be in correct place in the corresponding time, and the description to all kinds of Target space positions then must be based on them Corresponding coordinate system.Owing to the data class of space situation awareness is various, relate to multiple subject, and at different subjects In the description of object of study is had conventional coordinate system, as in describing the solar system during motion of each major planet the civil day heart yellow Road coordinate system；The inertial coodinate system of this planet, the description to satellite itself is generally used when describing the satellite motion of a certain planet Then use satellite body coordinate system；When describing the fixing target on planetary surface, then use the fixed coordinate system of this planet；Right In the description of spatial environments data, if radiation zone is frequently with geomagnetic coordinate system, magnetic field of the earth data are then accustomed to using the earth's core sun Magnetospheric system of coordinates.

As can be seen here, the coordinate system that relates to is various is the still another feature of space-air-ground integration situation expression engine, be relating to So the data of multi-coordinate are together unified shows, then have to solve is the mutual transfer problem between these coordinate systems, Reference coordinate for the comprehensive all kinds of Situation Awareness data of this present invention constructs coordinate transformation relation figure as shown in Figure 2, this turn The relation of changing covers reference coordinate conventional in the range of the solar system, all kinds of orbit coordinates relevant to extraterrestrial target, body coordinate, The geocentrical various magnetosphere reference coordinates etc. relevant to spatial environments.Making in order of coordinate relation is established for viewpoints' integration Basis.

Data type expressed by space-air-ground integration situation expression engine is various, space scale and distance is big, relate to coordinate system Many, viewpoints' integration to reach satisfied purpose, it is necessary to is designed for these features.Prior art be primarily present as Lower problem:

Problem one, contains all kinds of states such as planet, spacecraft, ground surface or terrain, spatial environments due to space-air-ground integration engine The Visualization of gesture perception data, if only with a kind of viewpoints' integration method of browsing objective in situation expression engine, being difficult to Meet requirement, as browse the viewpoints' integration method of spacecraft use ground surface or terrain then there will be when browsing horizon tilt, nothing Method carries out a series of problems affecting Consumer's Experience such as rotation around landform focus.

Problem two, comprehensive analysis viewpoints' integration method, browsing of viewpoint mainly has two class actions: a class is to vow around a direction Amount rotates to an angle, and an other class is by during scaling carrying out displacement by scale value.In the situation with desktop computer as platform Expressing in engine, viewpoints' integration is mainly realized by mouse interactive interface, it is generally the case that directly by mouse movement Be mapped to the interactive controlling that can realize viewpoint in the anglec of rotation of viewpoint and scale value with roller rolling amount, this method maps Relation is simple, it is simple to realize, and mouse is dynamic how many, and the corresponding angle of rotation that viewpoint is the most corresponding, roller turns how many, and viewpoint is just Corresponding scaling is how many, and the conversion of mouse stops viewpoint change and stops the most at once, and this interaction effect is stiff, does not has innervation.

Problem three, when needing from the current target paid close attention to, viewpoint is switched to another one target, can use Immediate Mode, After the associated objects that i.e. user setup is new, scene occurs the target of new association immediately.This viewpoint switch mode realizes simply, But it is a lack of the viewpoint transition from a position to another one position, it appears the most stiff, the most vividly, especially from whole When the solar system is switched to the earth satellite, this method seems the loftiest.

Problem four, the one of space-air-ground integration situation expression engine is big, and feature is exactly that space-time span is huge, wants to realize the most greatly Under yardstick, fine expression of all kinds of extraterrestrial targets is necessary for overcoming due to the excessive jitter problem caused of floating number round-off error, trembles The series of problems such as dynamic meeting causes some part of object to be ruptured by uncertain cutting, triangle gridding, texture entanglement.

Summary of the invention

It is an object of the invention to provide a kind of viewpoints' integration method of space-air-ground integration situation expression engine and band inertia thereof, use To solve the most lively problem of the problems referred to above two.

For achieving the above object, the solution of the present invention includes:

The viewpoints' integration method of the band inertia of space-air-ground integration situation expression engine, the viewpoints' integration method of described band inertia is such as Under:

$V_{\mathrm{angle}}^n=V_{\mathrm{angle}}^{n-1}\×D_{\mathrm{angle}}$

$V_{\mathrm{factor}}^n=V_{\mathrm{ractor}}^{n-1}\×D_{\mathrm{factor}}---\left(11\right)$

V_angle=F(△x,△y)

V_factor=G (△ d) (9)

In formula (9), V_angleIt is the viewpoint angular velocity of rotation around setting direction vector, V_factorIt it is the scaling speed of viewpoint； F (△ x, △ y) is that (△ x, △ y) arrives V_angle, set mapping function；G (△ d) is △ d to V_factor, set Mapping function, △ x and △ y are horizontal rotation amount of movement and the vertical rotary amount of movement of input of input, the scaling of △ d input Rolling amount；In formula (11)It is the angular velocity of rotation of current scene frame,It is the angular velocity of rotation of a upper scene frame,It is the scaling speed of present frame,It is the scaling speed of previous frame, D_angle、D_factorIt is respectively damping due to rotation Coefficient and scaling damped coefficient, their value is between 0 to 1.

The space-air-ground integration situation expression engine of the viewpoints' integration method with inertia, including the viewpoints' integration module of band inertia:

$V_{\mathrm{angle}}^n=V_{\mathrm{angle}}^{n-1}\×D_{\mathrm{angle}}$

$V_{\mathrm{factor}}^n=V_{\mathrm{ractor}}^{n-1}\×D_{\mathrm{factor}}---\left(11\right)$

V_angle=F(△x,△y)

V_factor=G (△ d) (9)

In formula (9), V_angleIt is the viewpoint angular velocity of rotation around setting direction vector, V_factorIt it is the scaling speed of viewpoint； F (△ x, △ y) is that (△ x, △ y) arrives V_angle, set mapping function；G (△ d) is △ d to V_factor, set Mapping function, △ x and △ y are horizontal rotation amount of movement and the vertical rotary amount of movement of input of input, the scaling of △ d input Rolling amount；In formula (11)It is the angular velocity of rotation of current scene frame,It is the angular velocity of rotation of a upper scene frame,It is the scaling speed of present frame,It is the scaling speed of previous frame, D_angle、D_factorIt is respectively damping due to rotation Coefficient and scaling damped coefficient, their value is between 0 to 1.

The present invention is by setting rational damped coefficient, and when input quantity stops transformation, velocity amplitude does not also have vanishing, corresponding Viewpoint change also will carry out, until speed is zero to stop transformation, this viewpoints' integration mode, meeting from environment viewing is experienced There is the sensation of inertia to a kind of target of people, make the most lively.

Accompanying drawing explanation

Fig. 1 is nomogram；

Fig. 2 is space coordinate conversion relation；

Fig. 3 is the tree-shaped structure charts of roomage state data；

Fig. 4 is classification classification viewpoints' integration method；

Fig. 5 is horizontally oriented viewpoint and rotates schematic diagram；

Fig. 6 is that eye coordinate converts schematic diagram；

Fig. 7 is that viewpoint local coordinate system defines method schematic diagram；

Fig. 8 is continuous viewpoint translation mode schematic diagram；

Fig. 9 is spherical linear interpolation schematic diagram；

Figure 10 is that target is at viewpoint and the schematic diagram of heliocentric ecliptic coordinate system；

Figure 11 is the frustum schematic diagram of perspective projection；

Figure 12 is that perspective parameter dynamically sets schematic diagram；

Figure 13 is solar system global view；

Figure 14 is Mars view；

Figure 15 is whole world TEC arrangement view；

Figure 16 is underground browse view；

Figure 17 is gps satellite view.

Detailed description of the invention

The present invention will be further described in detail below in conjunction with the accompanying drawings.

Space-air-ground integration situation expression engine, is by terrestrial space, the farther moon, planet or even by ionosphere, radiating layer Deng visualization, including one of them greatly to the whole solar system, little to a ground earth station, and around earth station Landform, extraterrestrial target can catalogue simultaneously, spatial environments that all kinds of situation data such as spatial environments are unified to show imitative True platform.

On the basis of existing technology, in order to solve the problems pointed out in background technology, the present invention proposes multiple respectively Solution.Implementation below only gives the method expressed corresponding to engine.

Mutual more lively in order to make, the invention provides a kind of viewpoints' integration method of band inertia.

Comprehensive analysis viewpoints' integration method, browsing of viewpoint mainly has two class actions: a class is around a direction Vector Rotation one Determining angle, an other class is by during scaling carrying out displacement by scale value.△ x and △ y be input horizontal rotation amount of movement and The vertical rotary amount of movement of input, the scaling rolling amount of △ d input, in the situation expression engine that desktop computer is platform, depending on Point control is mainly realized by mouse interactive interface, the movement of mouse and rolling corresponding to viewpoints' integration of mouse roller Two class actions.When mouse moves, the mainly position of mouse produces change, and in the present embodiment, input equipment is mouse, △ x and △ y is respectively mouse horizontal and vertical amount of movement on screen, the scaling rolling amount that △ d is corresponding when being roller rolling. Prior art can realize regarding in the direct anglec of rotation that mouse movement and roller rolling amount are mapped to viewpoint and scale value The interactive controlling of point, i.e. uses formula (8) to map.

Angle=F(△x,△y)

Factor=G (△ d) (8)

In formula, Angle is the viewpoint anglec of rotation around a direction vector, and F (△ x, △ y) is (△ x, △ y) reflecting to Angle Penetrate function；Factor is scale value during viewpoint scaling, and G (△ d) is the mapping function of △ d to factor.

The most this method, mapping relations are simple, it is simple to realize, but interaction effect is stiff, does not has innervation, and mouse is dynamic many Few, that viewpoint is the most corresponding corresponding angle of rotation, roller turns how many, and the scaling of viewpoint just correspondence is how many, and the conversion of mouse stops Only viewpoint change stops the most at once.In order to make environment viewing more natural, having innervation, as the formula (9), the present invention will Mouse movement and roller rolling amount are mapped in the angular velocity of rotation of viewpoint and scaling speed rather than the original anglec of rotation With on zoom factor, say, that in formula (9), V_angleIt is the viewpoint angular velocity of rotation around setting direction vector, V_factor It it is the scaling speed of viewpoint；F (△ x, △ y) is that (△ x, △ y) arrives V_angle, set mapping function；G (△ d) is that △ d arrives V_factor, set mapping function.

V_angle=F(△x,△y)

V_factor=G (△ d) (9)

The corresponding anglec of rotation then can be represented by the following formula with scale value:

Angle=V_angle×△t

factor=V_factor× △ t (10)

In formula (10), △ t takes the time interval drawing adjacent two frame scenes.After mouse moves, be may determine that by formula (9) The angular velocity that viewpoint rotates, then may determine that the current scene frame viewpoint anglec of rotation relative to a upper scene frame by formula (10) Degree, can't complete viewpoints' integration only by this two step, because the angular velocity of rotation V that mouse determines when moving every time_angleIt is One constant, such viewpoint will rotate down always, to this end, present invention introduces damped coefficient D, before every frame scene drawing, Velocity amplitude is used damping conversion, is shown below:

$V_{\mathrm{angle}}^n=V_{\mathrm{angle}}^{n-1}\×D_{\mathrm{angle}}$

$V_{\mathrm{factor}}^n=V_{\mathrm{ractor}}^{n-1}\×D_{\mathrm{factor}}---\left(11\right)$

In formula (11)It is the angular velocity of rotation of current scene frame,It is the angular velocity of rotation of a upper scene frame, It is the scaling speed of present frame,It is the scaling speed of previous frame, D_angle、D_factorValue between 0 to 1.This Sample rendering through multiframe, angular velocity of rotation will move closer in 0, thus conversion of stopping the rotation.

Because the frame number that rotary speed is as rendering is gradually reduced, set rational damped coefficient, when mouse stops transformation Time, velocity amplitude does not the most become 0, and corresponding viewpoint change also will be carried out, and is 0 to stop transformation until speed, this viewpoint control Mode processed, can have the sensation of inertia, so the present invention is this mapping mode from environment viewing is experienced to a kind of target of people It is referred to as the viewpoints' integration of band inertia.Determination mainly demand and experience according to user as damping coefficient determines, this Bright by practice find when damped coefficient takes about 0.92, preferable viewing experience can be obtained.The conversion process of scaling and rotation Turn similar, repeat no more here.

Present invention also offers a kind of classification hierarchical objectives browsing method.

Then it is difficult to meet requirement for a kind of viewpoints' integration method solved in situation expression engine only with browsing objective, impact The problem of Consumer's Experience, comprises the following steps that

Target classification: judge that target belongs to ball target and still falls within aspheric class target；If target belongs to aspheric class target, then Use general viewpoints' integration method；

Distance classification: if ball target, it is judged that it is that High eye point browses or nearly sphere browses, if High eye point browses, then Use general viewpoints' integration method；If nearly sphere browses, then use special viewpoints' integration method；

General viewpoints' integration method includes: rotates around target, scale and the viewpoints' integration method of direction of visual lines control；Special Viewpoints' integration method include: the viewpoints' integration method of horizon level, viewpoint are not passed through the viewpoints' integration method of landform, are regarded The viewpoints' integration method that point rotates around front point.

Introduce above-mentioned various viewpoints' integration method in detail below.Although the present invention carries out classification of classifying to viewpoints' integration method, but Being viewpoints' integration method still some general implementation method of different target classification, one is to rotate around target, and two is contracting Putting, three is direction of visual lines control, and above-mentioned three kinds of viewpoints' integration methods belong to prior art.

Rotate around target

As it is shown in figure 5, in coordinate system O residing for object observing₁In-XYZ, after viewpoint rotates λ degree in the horizontal direction, i.e. regard Point P rotates to figure P ' position after rotating λ degree about the z axis, and transformation relation is:

P′=R_z(λ) P (1)

In formula

$R_z\left(\mathrm{\λ}\right)=\left[\begin{array}{ccc}\cos \mathrm{\λ}& -\sin \mathrm{\λ}& 0\\ \sin \mathrm{\λ}& \cos \mathrm{\λ}& 0\\ 0& 0& 1\end{array}\right]---\left(2\right)$

In like manner can rotate around object observing in vertical direction viewpoint, the transformation for mula i.e. rotated around X-axis is:

P′=R_x(λ) P (3)

In formula

$R_x\left(\mathrm{\λ}\right)=\left[\begin{array}{ccc}1& 0& 0\\ 0& \cos \mathrm{\λ}& -\sin \mathrm{\λ}\\ 0& \sin \mathrm{\λ}& \cos \mathrm{\λ}\end{array}\right]---\left(4\right)$

Zoom control

Zooming in and out object observing and can be moved into by viewpoint and realize away from object observing, the scaling motor process of viewpoint can To be summarized as:

P '=factor P (5)

Wherein P is the position that viewpoint is original, position after P ' viewpoint scaling, and factor is zoom factor, and factor > 0, As factor > l time, it is achieved be to reduce effect；When factor < when 1, it is achieved be amplification effect.

Direction of visual lines controls

In the situation expression engine of the present invention, for ensureing that observer can see object observing, it is necessary to assure the Z of eye coordinate Direction of principal axis points to object observing.As shown in Figure 6: O₂-XYZ coordinate system is eye coordinate.Mesh is observed for ensureing that Z axis points to Mark, eye coordinate rotates-H angle the most about the z axis, the most again around X-axis, coordinate system is rotated-p angle, and now Z axis points to Object observing.

After being converted by direction of visual lines above, object observing is placed on field of view center, and now, eye coordinate is again rotating around X Axle and Y-axis carry out rotating and can realize observed object at panning effect vertically and horizontally, rotate about the z axis, can realize Whole scene is around the rotation effect at viewpoint center.

When above viewpoints' integration method may be used for the High eye point of ball target and other aspheric classification target viewpoints' integration, for Ball target and the aspheric classification target main distinction be: when browsing ball target, viewpoint does not the most enter ball interior, And the viewpoints' integration method that nearly sphere uses when browsing is different from control method during High eye point.

For ball target, the method preventing viewpoint from entering target internal is plus following Rule of judgment when zoom control:

|△P′|>R (6)

Wherein | △ P ' | represents the viewpoint distance to target's center, and R is the radius of sphere target.

When nearly sphere browses, during such as the browse displays of Earth's Terrain, in order to allow environment viewing more conform to the life experience of people, Have some special requirements to viewpoints' integration, such as, it is ensured that horizon is level, viewpoint can not pass through the landform of fluctuating, Viewpoint can be around certain some rotation etc. in front, and the viewpoints' integration method of they respectively correspondingly horizontal line levels, viewpoint does not passes through ground The viewpoints' integration method of shape, the viewpoints' integration method that viewpoint rotates around front point, this several method falls within prior art. For without loss of generality, below just as a example by the earth that we are familiar with, the spy that realize when these nearly spheres browse is discussed in detail respectively The different concrete viewpoints' integration method required:

Horizon level

First one local coordinate system O ' of definition_g-X ' Y ' Z ', the definition method of this coordinate system is as it is shown in fig. 7, with viewpoint center Line O with the earth's core_oO_EBe zero with ground intersection point G, with the earth's core to the direction of G point as Z ' direction of principal axis, at G point Direct north be Y ' direction of principal axis, with the direction, due east at G point as X ' direction of principal axis.

In order to allow near the ground browsing time horizon in visual field, be in level, then must assure that eye coordinate O_o-X_oY_oZ_o's X_oAxle and local coordinate system Z ' axle are in plumbness all the time, and now, the pitching of viewpoint can be by around X_oThe rotation of axle is real Existing, the left and right of viewpoint browses and only need to allow eye coordinate O_o-X_oY_oZ_oZ ' direction of principal axis around local coordinate system carries out rotating i.e. Can realize.

Viewpoint does not pass through landform

Viewpoint to be realized does not passes through landform, except needing to meet the Rule of judgment of formula (6), when near the ground browsing, it is necessary to Calculate the height above sea level of viewpoint position in real time, it is ensured that its height value is higher than the ground point height value on corresponding longitude and latitude, I.e. meet the condition of formula (7):

H_o>H_g(7)

Wherein H_oRepresent the height above sea level that viewpoint position is corresponding, H_gRepresent the ground corresponding to longitude and latitude identical with viewpoint The height value of cake.

Viewpoint rotates around front point

Browse in the landform that carries out near the ground, when running into impact point interested, during such as a certain seat mountain, a certain seat building, may Needing to carry out this ground target around observing, in order to realize this function, the present invention sets up one with point of interest for initial point Local coordinate system, the definition method of this coordinate system and preceding office portion coordinate system O '_g-X ' Y ' Z ' is identical, simply coordinate origin Different.After establishing local coordinate system, in the coordinate system, the spinning solution represented by formula (1) is used to carry out viewpoint position Put conversion, allow viewpoint carry out posture changing around the Z axis rotation of local coordinate system, so can complete viewpoint and rotate around point of interest, Generally take the intersection point of sight line and the earth as point of interest.

Present invention also offers a kind of viewpoint across yardstick seamless handover method.

When needing from the current target paid close attention to, viewpoint is switched to another one target, Immediate Mode, i.e. user can be used After new associated objects is set, scene occurs the target of new association immediately.This viewpoint switch mode realizes simply, but Lack the viewpoint transition from a position to another one position, it appears the most stiff, the most vividly, especially from the whole sun When system is switched to the earth satellite, this method seems the loftiest.In order to user one seamless switching mistake naturally Journey, viewpoint switch mode is improved by the present invention, in addition to providing Immediate Mode switching mode, also provides for continuous mode Viewpoint switch, i.e. viewpoint are not directly to target location, but move to target location along certain path from current location. Owing to the span of the situation expression engine of the present invention is relatively big, contain whole solar Situation Awareness target, the therefore present invention Use conversion regime linearly, the effect of seamless switching can either be reached, facilitate implementation again.Conversion regime linearly is i.e. In the linearly path continuous transformation of given time to appointed place.Straight linear formula for interpolation is relatively simple, such as following formula:

$P=\frac{B-A}{|B-A|}\&times;\mathrm{Dis}---\left(12\right)$

In formula (12), P is interpolation point position vector, and A is the start position vector of viewpoint switch, and B is the end of viewpoint switch Point position vector, Dis is the interpolation point air line distance to starting point.When view distance target farther out time, use linearly change Mode.Refer to farther out: as from the solar system overall situation to each celestial body, more closely refer to: situation about advancing around the earth, such as viewpoint It is transferred to U.S. overhead from Over China.

When view distance target is relatively near, as from earth overhead a little to another of the earth overhead time, if or using straight The mode of line, easily through the earth during viewpoint translation, makes conversion effect have a greatly reduced quality (as shown in Figure 8, dotted line table Show through the earth), provide another conversion regime globally for this present invention, use the mode globally changed to keep away Exempt to pass through the problem of the earth.

Sphere to be realized roams, it is necessary to use spherical linear interpolation techniques, this interpolation along between two key points at ball Shortest arc line on face is carried out.As it is shown in figure 9, on a two dimensional surface, vector A is ω with vector B angle, to Amount P is that θ, P can be obtained by the spherical linear interpolation between A, B with vector A angle:

P=α A+ β B (13)

We can be in the hope of α and β to give following three conditions:

$\left\{\begin{array}{c}\left|P\right|=1\\ A\&CenterDot;P=\cos \mathrm{\&theta;}\\ A\&CenterDot;B=\cos \mathrm{\&omega;}\end{array}\right.---\left(14\right)$

Thus obtain:

$P=A\frac{\sin (\mathrm{\&omega;}-\mathrm{\&theta;})}{\sin \mathrm{\&omega;}}+B\frac{\sin \mathrm{\&theta;}}{\sin \mathrm{\&omega;}}---\left(15\right)$

By being applied in combination of viewpoints' integration of the present invention and view point switching method, it is possible to achieve space-air-ground integration situation is expressed and drawn The comprehensive observation of all kinds of targets and seamless switching in holding up.

Present invention also offers a kind of jitter eliminating method.

The big feature of the one of the space-air-ground integration situation expression engine of the present invention is exactly that space-time span is huge, wants to realize the most greatly Under yardstick, fine expression of all kinds of extraterrestrial targets is necessary for overcoming due to the excessive jitter problem caused of floating number round-off error, trembles The series of problems such as dynamic meeting causes some part of object to be ruptured by uncertain cutting, triangle gridding, texture entanglement.

In engine is expressed in integration, owing to the yardstick of expressed target has the biggest gap, little to the most several on ground The earth station of rice, the big sun to diameter 1,392,000 km, shake to be eliminated and relate to the perspective projection of d engine The setting of parameter.Being the frustum in perspective projection shown in Figure 11, frustum is the shape after pyramid is truncated, Frustum region is the viewing area in three-dimensional scenic, and image video card can be near in frustum when carrying out image rendering Cutting face is mapped between 0 to 1 in depth buffer district to the scope between remote cutting face, the most any between frustum The depth value of object all become certain number between 0 to 1.If nearly cutting face is relatively big to the distance between remote cutting face, Shake can be caused equally due to round-off error.The target size difference that the space-air-ground integration situation expression engine of the present invention is expressed Huge, the unified perspective projection parameter (nearly cutting face and remote cutting face) that only one energy of setting is suitable for all yardsticks must cause Occurring the phenomenons such as shake during too small objective expression, therefore the present invention uses the dynamic setting method of perspective projection parameter, according to not The size of same target sets the nearly cutting face of perspective projection and remote cutting face, it is ensured that both can completely expresses target, again can Ensure precision.

Concrete method to set up such as Figure 12, first calculates the radius R(maximum circumradius that object outsourcing encloses) and target Center is to distance dis at viewpoint center, and right back-pushed-type (21) calculates nearly cutting face zNear and remote cutting face zFar:

zNear=dis-R

ZFar=dis+R (21)

Further, owing to shake further relates to floating number problem, so currently mainly having two kinds of think ofs processing in floating number problem Road: one be the floating number using higher precision to reduce round-off error, but at present the GPU of main flow is 32 floating numbers, Even if using double-precision floating point type data when outside calculates, single precision still can be truncated into when incoming GPU shows Data.The most presently mainly utilize another thinking to solve this problem, i.e. utilize less floating number to carry out thing Volume drawing, the foundation of this thinking is that the floating-point near initial point has less round-off error and the feature of higher precision.Want real The anti-jitter of existing the second thinking must utilize local coordinate to realize, will the target big floating-point from heliocentric ecliptic coordinate system Number Coordinate Conversion shows in the local coordinate of little floating number, all kinds of planet Situation Awareness in comprehensive space-air-ground integration The demand that datum target and the earth show, the present invention uses the local coordinate of initial point centered by viewpoint to realize jitter elimination.

As shown in Figure 10, S-XYZ is the coordinate system using big floating number, is a day heart ecliptic in space-air-ground integration engine Coordinate system, O-X ' Y ' Z ' is viewpoint local coordinate system, and P point is impact point, if the coordinate that P point is in S-XYZ is (X, Y, Z)^T, P point coordinate in O-X ' Y ' Z ' is (△ X, △ Y, △ Z)^T, then observed object is transformed to viewpoint local seat by day heart ecliptic coordiantes The formula of the coordinate of mark system is as follows:

$\left[\begin{array}{c}\mathrm{\&Delta;X}\\ \mathrm{\&Delta;Y}\\ \mathrm{\&Delta;Z}\end{array}\right]=M\left[\begin{array}{c}X\\ Y\\ Z\end{array}\right]+T---\left(20\right)$

Rotation under respectively viewpoint local coordinate ties up to heliocentric ecliptic coordinate system of M, T and transposed matrix in formula (20).

Calculate target after viewpoint local coordinate system, then carry out the drafting of target with viewpoint for initial point, can realize with less Floating number replace the purpose of big floating number, thus complete the effect of anti-jitter.Comprehensive utilization two kinds of jitter elimination above Method, it is possible to achieve preferably anti-jitter effect, it is thus achieved that the more situation of natural reality is expressed.

Terrain rendering under integrated frame

Space-air-ground integration situation expression engine is differentiating gound-mapping integrated with the maximum difference of existing engine more in the whole world To having accurate time-space relationship, comprise in the middle of the unified platform of the sun, each major planet, all kinds of space situation awareness data. The most general employing pyramid model of differentiating organizes globally graphic data more, and first this technology presses longitude and latitude layering the whole world Different layers and block prestore, and when the viewpoint moves, will not unload from internal memory regarding Intrapyramidal terrain block, with new Terrain block replace, when viewpoint is when the earth is close, use fine terrain block to replace coarse terrain block, away from time, then Replace fine terrain block soon by coarse landform, finally realize the Fast rendering of globally graphic data.Conventional method is main Being for ground visualization needs, do not account for the autobiography of the earth, revolution and the relation with other planets, data are adjusted Degree and the concrete coordinate having only to consider each terrain tile under ground is admittedly when rendering.In order to conventional method can be answered The integration using the present invention is expressed under framework, must the Coordinate Conversion of original earth coordinates be arrived when carrying out data dispatch Coordinate under day heart ecliptic system.Current data and method of partition are usually in units of longitude and latitude it may first have to be transformed into the earth Fixed coordinate system, is then transitioned to earth inertial coordinates system, is finally transformed into heliocentric ecliptic coordinate system and realizes corresponding ground figurate number According to the accurate drafting in showing scene in whole space-air-ground integration situation.

Present invention also offers the viewpoint method to set up that a kind of target is relevant.

Space-air-ground integration situation expression engine finally to become one can show that the whole solar system is all kinds of visible and sightless The system of space situation awareness data, although data class to be expressed is various, space scale and change in location are huge, but also It not irregular following.From the point of view of time-space relationship, we are it appeared that Various types of data has a father node, such as each major planet Make revolution motion around the sun, then the sun can regard the father node of each major planet as；The moon and Earth's orbit spacecraft are around landing Ball moves, then the earth can regard the moon and the father node of all kinds of Earth's orbit spacecraft as；The ground target such as earth station, Although the earth relatively is static, but the earth still can regard the father node of these targets as, and these corresponding targets are just It it is the child node of the earth.The rest may be inferred, and whole solar Various types of data just can be with a tree as shown in Figure 3 Organize, thus constitute an orderly situation and express scene, in this scene tree, each spatial alternation of father node Child node will be delivered to, in conjunction with coordinate system transformation relation above, as long as each destination node that situation expresses scene ensures Spatial transform relation between itself and father node is correct, can ensure that whole roomage state expresses each object space in engine The most accurately expressing of position.

Viewpoint can regard an imaginary observer in three-dimensional scenic as, if allowing absolute according in space of this observer Position is placed in scene, although can also realize the observation to scene, but all kinds of planets and extraterrestrial target in the whole solar system In the middle of being at constantly moving, if observer to be realized and the geo-stationary of extraterrestrial target, then observer is subjected to The spatial alternation the same with extraterrestrial target, the most not only waste calculates resource, and easily makes mistakes.In order to overcome this problem, All kinds of targets that observer expresses with situation are associated by the present invention, by observer as an extraterrestrial target, refer to for observer A fixed father node, when so needing to pay close attention to which target, the father node just specifying this target to be observer, observer only bears Duty and the space paying close attention to target convert, such as geo-stationary problem above, as long as ensureing that observer is at father node admittedly In position fixing system, invariant position all can solve easily.Now by changing observer position in father node and attitude, Realize concern the arbitrarily angled of target is browsed.Associate the most according to the observation is the coordinate system type of father node, it is also possible to Realize some special results of browse, as observer is associated with the inertial coodinate system of the earth, then the rotation of the observable earth Motion, is associated with the fixed coordinate system of the earth then it is observed that the effect that the stars change in positions.

According to said method, we have developed space-air-ground integration situation expression engine, be viewpoint such as Figure 13 and the sun is associated Time solar global view, figure illustrates the circumsolar ruuning situation of each major planet.Viewpoint switch side by the present invention Method, can naturally be transitioned into any planet by viewpoint, if Figure 14 is the viewpoint switch view near Mars.Figure 15 is The view that viewpoint switch is distributed to Earthwatch whole world TEC.Figure 16 is the viewpoint somewhere at the earth's surface effect when browsing landform Really, the DEM resolution of figure mesorelief is 8.5 meters, and image rate respectively is 1 meter.Figure 17 is that viewpoint is when being associated with gps satellite View, lines are the tracks of this satellite.

Claims (2)

1. the viewpoints' integration method of the band inertia of space-air-ground integration situation expression engine, it is characterised in that the viewpoints' integration method of described band inertia is as follows:

1) the horizontal rotation amount of movement of input, the vertical rotary amount of movement of input and viewpoint mapping relations between the angular velocity of rotation setting direction vector, i.e. V are set up_angle=F (Δ x, Δ y) (9 1)；

Set up the mapping relations between vertical rotary amount of movement and the scaling speed of viewpoint of the horizontal rotation amount of movement of input, input, i.e. V_factor=G (Δ d) (9 2)；

2) damping due to rotation coefficient is introduced formula (9 1), and scaling damped coefficient is introduced formula (9-2), obtain equation below:

3) when input level amount of rotational movement and vertical rotary amount of movement, according to formula (11), control angular velocity that viewpoint rotates and scaling speed gradually levels off to 0, it is achieved the viewpoints' integration of band inertia；

In formula (9-1) and (9-2), V_angleIt is the viewpoint angular velocity of rotation around setting direction vector, V_factorIt it is the scaling speed of viewpoint；(Δ x, Δ y) are that (Δ x, Δ y) arrive V to F_angle, set mapping function；(Δ d) is Δ d to V to G_factor, the mapping function set, Δ x and Δ y is the horizontal rotation amount of movement and the vertical rotary amount of movement of input of input, and Δ d is the scaling rolling amount of input；In formula (11)It is the angular velocity of rotation of current scene frame,It is the angular velocity of rotation of a upper scene frame,It is the scaling speed of present frame,It is the scaling speed of previous frame, D_angle、D_factorBeing respectively damping due to rotation coefficient and scaling damped coefficient, their value is between 0 to 1.

2. use the space-air-ground integration situation expression engine of the viewpoints' integration method of band inertia described in claim 1, it is characterised in that include that the viewpoints' integration module of band inertia, the function of described viewpoints' integration module are:

1) the horizontal rotation amount of movement of input, the vertical rotary amount of movement of input and viewpoint mapping relations between the angular velocity of rotation setting direction vector, i.e. V are set up_angle=F (Δ x, Δ y) (9 1)；

Set up the mapping relations between vertical rotary amount of movement and the scaling speed of viewpoint of the horizontal rotation amount of movement of input, input, i.e. V_factor=G (Δ d) (9 2)；

2) damping due to rotation coefficient is introduced formula (9 1), and scaling damped coefficient is introduced formula (9-2), obtain equation below:

3) when input level amount of rotational movement and vertical rotary amount of movement, according to formula (11), control angular velocity that viewpoint rotates and scaling speed gradually levels off to 0, it is achieved the viewpoints' integration of band inertia；

In formula (9-1) and (9-2), V_angleIt is the viewpoint angular velocity of rotation around setting direction vector, V_factorIt it is the scaling speed of viewpoint；(Δ x, Δ y) are that (Δ x, Δ y) arrive V to F_angle, set mapping function；(Δ d) is Δ d to V to G_factor, the mapping function set, Δ x and Δ y is the horizontal rotation amount of movement and the vertical rotary amount of movement of input of input, and Δ d is the scaling rolling amount of input；In formula (11)It is the angular velocity of rotation of current scene frame,It is the angular velocity of rotation of a upper scene frame,It is the scaling speed of present frame,It is the scaling speed of previous frame, D_angle、D_factorBeing respectively damping due to rotation coefficient and scaling damped coefficient, their value is between 0 to 1.