CN104391311B - Passive location method on star based on GPS broadcast datas - Google Patents

Abstract

The invention provides a kind of passive location method on star based on GPS broadcast datas, including the measurement data for gathering satellite；The transition matrix M that body-fixed coordinate system is tied to satellite body system is calculated according to measurement data；Selection ellipsoid model of globe simultaneously obtains corresponding earth geometric parameter and earth ellipsoid face equation；Equation on the spot ball ellipsoid equation in parallel in target location is tried to achieve according to transition matrix M and tries to achieve target location coordinate.Measurement data is included comprising satellite real time positionAnd speedGPS broadcast datas, target angle measurement β_x、β_yAnd attitude angle data, the i.e. angle of pitchYaw angle γ, roll angle θ；GPS broadcast datas are obtained by satellite data bus, β_xAnd β_yObtained by load subsystem, attitude angle data is obtained by rail control subsystem.The present invention is using high-precision GPS broadcast data as the input quantity of system, it is ensured that the precision of calculating process parameters, then ensure that the precision of positioning result, while without the process processed under line, enhancing the autonomous computing capability on star.

Description

Passive location method on star based on GPS broadcast datas

Technical field

The present invention relates to satellite passive location technical field, in particular it relates to nothing on a kind of star based on GPS broadcast datas Source localization method.

Background technology

Outer space is total for the mankind, does not have national boundaries, target is positioned using satellite does not receive territory, territorial waters, territorial sky Limitation.Satellite passive location is that itself radiating radio signal is positioned to target using satellite reception target, with effect Distance is remote, good concealment the features such as, therefore be used widely.Satellite passive location technology is always satellite application technical research One of focus.

Satellite passive location process proposes requirement higher to the following ability of satellite：

(1) positioning principle is by the use of the direction vector of satellite position, attitude information and target relative satellite in itself as input, Therefore to satellite orbit determination in itself and determine appearance ability and propose requirement higher；

(2) in order to adapt to actual service condition, from from the point of view of security of system and ease of use, it is necessary to right The ageing and capacity of will of alignment system proposes certain requirement.

Traditional positioning flow provides recursion position and the speed data of satellite, positioning calculation precision phase using Attitude and orbit control system To relatively low, or target angle measurement data and attitude are determined to be processed under the laggard line of data down transmission, capacity of will is weaker.

The content of the invention

For defect of the prior art, the present invention proposes passive location side on a kind of star based on GPS broadcast datas Method, autonomous calculation process in high-precision observation data acquisition and quick star is capable of achieving using the present invention.The invention has fixed Position high precision, resource occupation be few and star on capacity of will it is strong the advantages of.

According to passive location method on the star based on GPS broadcast datas that the present invention is provided, comprise the following steps：

Step 1：Gather the measurement data of satellite；

Step 2：The transition matrix M that body-fixed coordinate system is tied to satellite body system is calculated according to measurement data；

Step 3：Selection ellipsoid model of globe simultaneously obtains corresponding earth geometric parameter and earth ellipsoid face equation；

Step 4：Equation on the spot ball ellipsoid equation in parallel in target location is tried to achieve according to transition matrix M and tries to achieve target location seat Mark.

Preferably, the measurement data is included comprising satellite real time positionAnd speedGPS broadcast datas, target Angle measurement β_x, target angle measurement β_yAnd attitude angle data, attitude angle data is the angle of pitchYaw angle γ, roll angle θ；The GPS is wide Multicast data is obtained by satellite data bus, β_xAnd β_yObtained by load subsystem, the attitude angle data is by rail control point System is obtained.

Preferably, the GPS broadcast datas, the target angle measurement and the attitude angle data are processed through recursion and are combined into Joint packet simultaneously adds time marking.

Preferably, the step 2 comprises the following steps：

Step 2.1：Unit vector of the satellite to target direction under satellite body coordinate system is calculated, specifically, in body Two target angle measurements under coordinate system are respectively β_x、β_y, then now unit vector of the satellite to target direction under satellite body system L₁It is expressed as：

Wherein, l₁, m₁, n₁Respectively projection of the line of sight direction under satellite body system x-axis, y-axis, z-axis；

Step 2.2：By the unit vector L of satellite to target direction₁It is transformed under orbital coordinate system, is expressed as：

IfThen L₂=M₁L₁,

Wherein, l₂, m₂, n₂Respectively projection of the line of sight direction under track system x-axis, y-axis, z-axis；

Step 2.3：By the unit vector L under orbital coordinate system₂It is transformed under body-fixed coordinate system, specially：With satellite Velocity is X-axis, and the reverse vector of the position vector of satellite is Z axis, and Z obtains being Y-axis with X-axis multiplication cross, then by orbit coordinate Unit vector L under system₂It is transformed under body-fixed coordinate system, is expressed as： By v_siComponent form be expressed as [v_x,v_y,v_z]^T, try to achieve this three unit vectors as follows：

According toTry to achieveWherein v_siIt is the velocity inertial of satellite in body-fixed coordinate system Expression, x, y, z is respectively coordinate of the satellite in the case where ground is admittedly；l₃, m₃, n₃Respectively line of sight direction is x-axis, y on ground admittedly Projection under axle, z-axis.[a₁,a₂,a₃]^T, [b₁,b₂,b₃]^T, [c₁,c₂,c₃]^TRespectively track system x-axis, y-axis, z-axis are admittedly on ground Under projection；

Step 2.4：Try to achieve the transition matrix M of body-fixed coordinate system to satellite body coordinate system：

M=M₂ ^TM₁ ^T

Preferably, the earth geometric parameter includes：

Major radius a：A=6378137 ± 2m；

The product GM of terrestrial gravitation and earth quality：GM=3.98600441500 × 10⁵km³/s²；

Rotational-angular velocity of the earth ω：ω=7292115 × 10^-11rad/s±0.150×10^-11rad/s。

Preferably, the step 4 comprises the following steps：

Step 4.1：Calculate the target location EQUATION x in satellite body coordinate system_T,b=Μ (x_T,e-x_S,e)；

Wherein,

x_T,bIt is the target location in satellite body coordinate system, x_T,eTarget location in being admittedly for ground, x_S,eIn being admittedly for ground Satellite position；

Step 4.2：By the longitude and latitude (L of any point on the earth_T, B_T) and geographical elevation (H_T) change to body-fixed coordinate system, obtain Equivalent equation：

Wherein,It is local radius of curvature in prime vertical, earth major radius a=6378137m, First eccentricity square e²=0.00669437999013；H_TIt is the geographical elevation of any point on the earth, L_TIt is any point on the earth Latitude, B_TIt is the longitude of any point on the earth；

Step 4.3：By x_T,b、x_T,eAnd x_S,eSubstitute into earth ellipsoid face equation；

Step 4.4：Simultaneous target location equation, equivalent equation and earth ellipsoid face equation, obtain target location.

Preferably, when body-fixed coordinate system approximately regards the coordinate system of fixed-axis rotation as, thenIts InIt is rotational-angular velocity of the earth vector, It is position of the satellite under body-fixed coordinate system Put, i.e., the GPS location that satellite data satellite data bus is given；It is speed of the satellite under body-fixed coordinate system, i.e. satellite number The GPS velocity be given according to bus.

Preferably, also comprise the following steps after the step 4：

The distance of-hypothesis target range celestial body is r, and β is obtained in measurement_x, β_yAfter angle, can be by satellite body coordinate system The lower orientation cosine angle for obtaining that measures is decomposed into position：

x_T,b=ru

Therefore have

x_T,e=x_S,e+Μ^-1x_T,b=x_S,e+rΜ^-1u

Substitute into the equation of earth ellipsoid face, obtain a quadratic equation with one unknown on r；This quadratic equation with one unknown is solved, is obtained To two roots, minimum solution is the distance solution of target location, and then obtains the position solution of target, and u is satellite to target direction Unit vector under satellite body system.

Compared with prior art, the present invention has following beneficial effect：

1st, the present invention is using high-precision GPS broadcast data as the input quantity of system, it is ensured that calculating process parameters Precision, then ensure that the precision of positioning result, while without the process processed under line, enhance on star from host computer energy Power；

2nd, the present invention achieves the satellite inertial velocity in body-fixed coordinate system with simple conversion regime, directly obtains immediately Transition matrix between orbital coordinate system and body-fixed coordinate system, it is to avoid inertial system and the cumbersome meter needed for body-fixed coordinate system conversion Calculate, it is ensured that computing resource occupancy is greatly reduced while conversion accuracy；

3rd, the present invention is used and constructs ellipsoid model of globe based on international standard, than flat the earth and spheroidal earth mould Type is more accurate.

Brief description of the drawings

The detailed description made to non-limiting example with reference to the following drawings by reading, further feature of the invention, Objects and advantages will become more apparent upon：

Fig. 1 is localization method FB(flow block) in the present invention；

Fig. 2 is that the angle measurement of load system in the present invention defines schematic diagram；

Fig. 3 is Satellite of the present invention with respect to body-fixed coordinate system speed and the transformational relation figure of satellite inertial velocity.

Specific embodiment

With reference to specific embodiment, the present invention is described in detail.Following examples will be helpful to the technology of this area Personnel further understand the present invention, but the invention is not limited in any way.It should be pointed out that to the ordinary skill of this area For personnel, without departing from the inventive concept of the premise, various modifications and improvements can be made.These belong to the present invention Protection domain.

Localization method disclosure satisfy that the target location accuracy that user proposes on star proposed by the present invention.From satellite development process In test case from the point of view of, the method rationally, it is reliable.With the fast development of space technology, satellite is in information support operation, branch Rescuing calamity aspect will play even more important effect, and this method will be provided for following low rail passive electronic investigation satellite positioning method With reference to and foundation.

In the present embodiment, as shown in Figure 1, Figure 2, Figure 3 shows, it is passive on the star based on GPS broadcast datas that the present invention is provided Localization method comprises the following steps：

Step 1：The measurement data of satellite is gathered, specifically, obtaining real-time comprising satellite by satellite data bus PositionAnd speedGPS broadcast datas, with reference to the target angle measurement β of load subsystem_x、β_yWith the appearance of rail control subsystem State angular data, the i.e. angle of pitchYaw angle γ, roll angle θ, are combined into the joint packet under synchronization after being processed through recursion And add time marking.

Step 2：The transition matrix M that body-fixed coordinate system is tied to satellite body system is calculated according to measurement data, is comprised the following steps：

Step 2.1：Unit vector of the satellite to target direction under satellite body coordinate system is calculated, specifically, such as Fig. 2 institutes Show, now two under satellite body coordinate system target angle measurement is respectively β_x、β_y, now satellite to target direction in satellite sheet Unit vector under system can be expressed as：

Wherein, l₁, m₁, n₁Respectively projection of the line of sight direction under satellite body system x-axis, y-axis, z-axis.

Step 2.2：By the unit vector L of satellite to target direction₁It is transformed under orbital coordinate system and is represented by：

IfThen L₂=M₁L₁。

Wherein, l₂, m₂, n₂Respectively projection of the line of sight direction under track system x-axis, y-axis, z-axis.

Step 2.3：By the unit vector L under orbital coordinate system₂It is transformed under body-fixed coordinate system.

Position coordinates (x, y, z) of the satellite under WGS-84 coordinate systems, i.e. body-fixed coordinate system is obtained according to joint packet, Satellite is (vx, vy, vz) with respect to the speed of WGS-84 coordinate systems, and inertia speed of the satellite under WGS-84 coordinate systems is can obtain with this Degree.

On the premise of required precision can meet Project Realization, body-fixed coordinate system can be regarded as the coordinate of fixed-axis rotation System, the velocity of following that actual speed vector should be by particle under the coordinate system is superimposed its speed relative to coordinate system, i.e. GPS The speed that system is given is formed.

As shown in Fig. 3, v_siRepresent heading of the satellite under inertial space, i.e. X in orbital coordinate system_oWhat axle was pointed to Direction, v_eRepresent the velocity of following that body-fixed coordinate system (fixed-axis rotation coordinate system) is provided for satellite site, v_seRepresent GPS systems The speed of the body-fixed coordinate system that the speed that system is provided, i.e. satellite are relatively rotated.

This transformational relation can be expressed as follows：

Wherein,It is rotational-angular velocity of the earth vector, For satellite is sat admittedly on ground Position under mark system, i.e., the GPS location that satellite data bus is given；It is speed of the satellite under body-fixed coordinate system, i.e. bus The GPS velocity for being given.

As X-axis, the reverse vector of the position vector of satellite is Z axis to velocity with satellite, and X is Y with the difference-product of Z axis Axle.So by the unit vector L under orbital coordinate system₂It is transformed under WGS-84 coordinate systems, can be expressed as：

Wherein,The respectively unit of orbital coordinate system X-axis, Y-axis, Z axis under WGS84 coordinate systems Vector.By v_siComponent form be expressed as [vx, vy, vz]^T, this three unit vectors can be tried to achieve as follows：

According toTry to achieve

Wherein, v_siIt is the expression of the velocity inertial in body-fixed coordinate system of satellite, x, y, z is respectively satellite in the case where ground is admittedly Coordinate；l₃, m₃, n₃Respectively projection of the line of sight direction in the case where ground is x-axis, y-axis, z-axis admittedly.[a₁,a₂,a₃]^T, [b₁,b₂, b₃]^T, [c₁,c₂,c₃]^TThe respectively projection of track system x-axis, y-axis, z-axis in the case where ground is admittedly.

Step 2.4：Try to achieve the transition matrix M of body-fixed coordinate system to satellite body coordinate system：M=M₂ ^TM₁ ^T

Step 3：Earth model is set,

Step 3.1：Selection reference ellipsoid model, specifically, having selected WGS-84 models as reference ellipsoid model, it four Individual basic geometric parameters are as follows：

Major radius：A=6378137 ± 2m

The product of terrestrial gravitation and earth quality：

GM=3.98600441500 × 10⁵km³/s²

Rotational-angular velocity of the earth：ω=7292115 × 10^-11rad/s±0.150×10^-11rad/s

Step 4：Solving target position coordinates,

Target location equation in satellite body coordinate system is

x_T,b=Μ (x_T,e-x_S,e)

In formula, M is transition matrix of the body-fixed coordinate system system to satellite body coordinate system.

Wherein, x_T,bIt is the target location in satellite body coordinate system, x_T,eTarget location in being admittedly for ground, x_S,eIt is ground Gu the satellite position in system；

It is assumed that using mean earth ellipsoid WGS-84 models, target is located on earth surface, the geography of any point of the earth Longitude and latitude (L_T, B_T) and geographical elevation (H_T) consolidate three-dimensional rectangular coordinate X on ground with it_T,e=[x_T,e y_T,e z_T,e]^TThe equivalent form of value For

Wherein,It is local radius of curvature in prime vertical, earth major radius a=6378137m, First eccentricity square e²=0.00669437999013.

Above formula can be write as the earth ellipsoid face equation under another form, i.e. WGS84 systems

How DF and location problem is considered as using the earth ellipsoid face equation under target location equation and WGS-84 systems Solve the problem of target location.In above-mentioned Nonlinear System of Equations, one has three equations and three unknown numbers.From geometrically For, if positioning solution is present, general direction finding line intersects with earth ellipsoid face can obtain two intersection points, and solve equation process In, two solutions will necessarily be also produced, the One Earth One Family other end bigger solution of distance need to be removed, the position of radiation source can be solved. Equation form used covers the consideration to height where target, reply target is not only capable of as in conventional solution and is located at The situation of earth surface.

If it is assumed that the distance of target range celestial body is r, β is obtained in measurement_x, β_yAfter angle, can be by satellite body coordinate System measures the orientation cosine angle for obtaining and is decomposed into position down：

x_T,b=ru

Therefore have

x_T,e=x_S,e+Μ^-1x_T,b=x_S,e+rΜ^-1u

Substitute into the equation of earth ellipsoid face, a quadratic equation with one unknown on r can be obtained.Solve this One- place 2-th Order side Journey, can obtain two roots, and minimum solution is the distance solution of target location.And then obtain the position solution of target.

But in earth elliptic equation, radius of curvature in prime vertical N is unknown for target locality, is that this can use alternative manner Solve.Consider that satellite and the N values of target are closer to, first by satellite N₀=N_SatValue is substituted into earth elliptic equation,

Wherein, N₀For：The initial value of target locality prime vertical radius；N_SatFor：Sub-satellite point prime vertical radius.

Ith iteration is calculated apart from r_i, then calculated target positions, the target for being calculated ith iteration estimation works as the fourth of the twelve Earthly Branches Tenth of the twelve Earthly Branches circle radius of curvature N_i, circulated with this, until target range convergence such as following formula.

|r_i-r_i-1|≤ε_r

Wherein ε_rIt is the range error thresholding of setting.

The characteristics of present invention requires high for satellite passive direction finding positioning to measure data precision, the position based on LEO-based GPS Put and speed data, devise the method that a set of passive target for ground or specified altitude assignment is positioned, including measurement The links, whole positioning flow such as data acquisition, Conversion Matrix of Coordinate are calculated, oval earth model is set, target location resolving Figure is as shown in Figure 1.The characteristics of present invention has played space-borne GPS measurements satellite position and speed data high precision, can be accurate To satellite body system and the transition matrix of body-fixed coordinate system, and this feature and the angle measurement of high accuracy target and attitude are determined into technology Collaboration is used, it is ensured that satellite enhances the autonomous computing capability on star to the positioning precision of target, improves satellite in information The emergent efficiency of the application fields such as support, disaster monitoring.The certainty of measurement possessed in current Practical Project can ensure this method Theory orientation precision be better than 3km.

Specific embodiment of the invention is described above.It is to be appreciated that the invention is not limited in above-mentioned Particular implementation, those skilled in the art can within the scope of the claims make various deformations or amendments, this not shadow Sound substance of the invention.

Claims (3)

1. a kind of passive location method on star based on GPS broadcast datas, it is characterised in that comprise the following steps：

Step 1：Gather the measurement data of satellite；

Step 2：The transition matrix M that body-fixed coordinate system is tied to satellite body system is calculated according to measurement data；

Step 3：Selection ellipsoid model of globe simultaneously obtains corresponding earth geometric parameter and earth ellipsoid face equation；

Step 4：Equation on the spot ball ellipsoid equation in parallel in target location is tried to achieve according to transition matrix M and tries to achieve target location coordinate；

The measurement data is included comprising satellite real time positionAnd speedGPS broadcast datas, target angle measurement β_x, target Angle measurement β_yAnd attitude angle data, attitude angle data is the angle of pitchYaw angle γ, roll angle θ；The GPS broadcast datas pass through Satellite data bus is obtained, β_xAnd β_yObtained by load subsystem, the attitude angle data is obtained by rail control subsystem；

The step 2 comprises the following steps：

Step 2.1：Unit vector of the satellite to target direction under satellite body coordinate system is calculated, specifically, in body coordinate Two target angle measurements under system are respectively β_x、β_y, then now unit vector L of the satellite to target direction under satellite body system₁Table It is shown as：

$L_1=\left[\begin{array}{c}{l}_1\\ m_1\\ n_1\end{array}\right]=\left[\begin{array}{c}cos\left({\mathrm{\β}}_x\right)\\ cos\left({\mathrm{\β}}_y\right)\\ \sqrt{1-{\cos }^2\left({\mathrm{\β}}_x\right)-{\cos }^2\left({\mathrm{\β}}_y\right)}\end{array}\right],$

Wherein, l₁, m₁, n₁Respectively projection of the line of sight direction under satellite body system x-axis, y-axis, z-axis；

Step 2.2：By the unit vector L of satellite to target direction₁It is transformed under orbital coordinate system, is expressed as：

IfThen L₂=M₁L₁,

Wherein, l₂, m₂, n₂Respectively projection of the line of sight direction under track system x-axis, y-axis, z-axis；

Step 2.3：By the unit vector L under orbital coordinate system₂It is transformed under body-fixed coordinate system, specially：Sweared with the speed of satellite It is X-axis to measure, and the reverse vector of the position vector of satellite is Z axis, and Z obtains being Y-axis with X-axis multiplication cross, then by under orbital coordinate system Unit vector L₂It is transformed under body-fixed coordinate system, is expressed as：By v_si's Component form is expressed as [v_x,v_y,v_z]^T, try to achieve this three unit vectors as follows：

$\left[\begin{array}{c}{c}_1\\ c_2\\ c_3\end{array}\right]=\left[\begin{array}{c}-x/\sqrt{x^2+y^2+z^2}\\ -y/\sqrt{x^2+y^2+z^2}\\ -z/\sqrt{x^2+y^2+z^2}\end{array}\right]$

$\left[\begin{array}{c}{b}_1\\ b_2\\ b_3\end{array}\right]=\left[\begin{array}{c}{v}_x/\sqrt{{v_x}^2+{v_y}^2+{v_z}^2}\\ v_y/\sqrt{{v_x}^2+{v_y}^2+{v_z}^2}\\ v_z/\sqrt{{v_x}^2+{v_y}^2+{v_z}^2}\end{array}\right]\×\left[\begin{array}{c}-x/\sqrt{x^2+y^2+z^2}\\ -y/\sqrt{x^2+y^2+z^2}\\ -z/\sqrt{x^2+y^2+z^2}\end{array}\right]$

According toTry to achieveWherein v_siIt is the table of the velocity inertial in body-fixed coordinate system of satellite Show, x, y, z is respectively coordinate of the satellite in the case where ground is admittedly；l₃, m₃, n₃Respectively line of sight direction is x-axis, y-axis, z on ground admittedly Projection under axle；[a₁,a₂,a₃]^T, [b₁,b₂,b₃]^T, [c₁,c₂,c₃]^TRespectively track system x-axis, y-axis, z-axis are in the case where ground is admittedly Projection；

Step 2.4：Try to achieve the transition matrix M of body-fixed coordinate system to satellite body coordinate system：M=M₂ ^TM₁ ^T。

2. passive location method on the star based on GPS broadcast datas according to claim 1, it is characterised in that the GPS Broadcast data, the target angle measurement and the attitude angle data process through recursion and are combined into joint packet and add the time to mark Know.

3. passive location method on the star based on GPS broadcast datas according to claim 1, it is characterised in that describedly Geometry of sphere parameter includes：

Major radius a：A=6378137 ± 2m；

The product GM of terrestrial gravitation and earth quality：GM=3.98600441500 × 10⁵km³/s²；

Rotational-angular velocity of the earth ω：ω=7292115 × 10^-11rad/s±0.150×10^-11rad/s。