CN102902282B - Based on the geographic tracking method that optical axis overlaps with the axes of inertia - Google Patents

Abstract

The invention discloses a kind of geographic tracking method overlapped with the axes of inertia based on optical axis.This method adopts space two point geometry algorithm according to object location data and own location information, the spatial attitude of real-time calculating carrier boresight, the space angle of boresight relative to carrier coordinate system is calculated again in conjunction with carrier space attitude and space coordinate transformation principle, servo control unit is given by this angle, adjusted the additional space attitude of turntable by servo control unit, thus complete the geographic tracking to target.This method is different from image tracking method from principle, is not therefore subject to the impact of cloud and mist and barrier, can avoid the problem of lose objects because strenuous vibration or sight line are blocked, significantly improve the scouting of Battlefield Weapons System and search with ability if use on board the aircraft.The present invention also can be used for the guidance device of various seeker, to improve the precision strike capability of target over the ground.

Description

Based on the geographic tracking method that optical axis overlaps with the axes of inertia

Technical field

The invention belongs to photoelectronic reconnaissance and target tracking domain, relate generally to a kind of geographic tracking method to target, particularly relate to a kind of geographic tracking method overlapped with the axes of inertia based on optical axis.

Background technology

The optronic tracker of Modern weapon system has the function to target reconnaissance and search and track.Current automatic tracking function is divided into laser, infrared, TV three kinds of tracking modes according to the form of target detector.The ultimate principle of these three kinds of tracking modes is: after target detector captures target, target scene is changed into electronic image by CCD (charge-coupled image sensor), again by signal processing unit to image miss the target measure after automatically export miss distance, then get poor device and miss distance is become electric signal as angular displacement amount feeding servo control unit, the boresight angle of optronic tracker is finally adjusted by servo control unit, thus reduction tracking error, realize the lasting tracking to target.Must clear target acquisition scene but the prerequisite applying these trackings is detector, if target is subject to cloud and mist, barrier blocks, or background environment and object spectral characteristic poor contrast, the target scene effect that obtains with detector will be made undesirable, cause optronic tracker to target tracking accuracy difference even lose objects, reduce armament systems and scout and search with ability.Occurred again afterwards utilizing geography information to realize the method for following the tracks of.

In March, 2012 published the paper that exercise question is " O-E Payload for UAV geographic tracking controls research " by " airborne computer " periodical.A kind of geographic tracking method and system that can use on photoelectronic reconnaissance O-E Payload for UAV of this paper.Proposing when having manipulation concussion or cloud cover in literary composition, adopting image trace technology meeting lose objects, so introduce geographic tracking method as the supplementary means of image tracking method, the problem to target fast Acquisition can be solved.First the method calculates the angle rotation relationship between carrier aircraft coordinate system and geographic coordinate system according to carrier aircraft spatial attitude, subsequently the target under geographic coordinate system is converted to " the pseudo-target " under carrier aircraft coordinate system, then under carrier aircraft coordinate system, calculate the space vector angle of " pseudo-target ", again the Space Angle angle value obtained is inputed to servo control unit, turntable angle is stablized by servo control unit adjustment, can fast Acquisition target.The optical axis not proposing O-E Payload system in the technical scheme that paper provides and the axes of inertia need the requirement overlapped, therefore only rely on the space vector angle calculating target and inputed to servo control unit, turntable angle is stablized by servo control unit adjustment, target can only be made to appear in the visual field of video camera, the target center position of target in visual field can not be ensured.So adopt separately the geographic tracking method in paper, can not keep the stable tracking of target Continuous.

Summary of the invention

The technical problem to be solved in the present invention is, for prior art Problems existing, and a kind of geographic tracking method that can be used alone under prerequisite overlapped with the axes of inertia at optical axis is provided.

Geographic tracking method provided by the invention comprises the following steps:

The first step, gathers the impact point data (λ, L, h) of target locating set output and the data (λ of current carrier aircraft location point₁, L₁, h₁, ψ_a, θ_a, γ_a, S), wherein λ, L, h are the longitude of impact point, latitude and height respectively; λ₁, L₁, h₁the current longitude of carrier aircraft, latitude and height respectively, ψ_a, θ_a, γ_abe current course angle, the angle of pitch and the roll angle of carrier aircraft in the ground under coordinate system respectively, S is the distance of current carrier aircraft to impact point;

Second step, is projected to the north orientation angle σ of impact point projection vector line segment in surface level projects by carrier aircraft with following formulae discovery carrier aircraft and impact point:

$\mathrm{\σ}=\arctan \frac{|\mathrm{\λ}-{\mathrm{\λ}}_1|\×R_M\×\cos L_1}{|L-L_1|\×R_N}$

R_M＝R_e(1-2e+3esin²L₁)

R_N＝R_e(1+esin²L₁)

Wherein, R_mthe radius of curvature of meridian of carrier aircraft current location, R_nbe the radius of curvature in prime vertical of carrier aircraft current location, e is ellipticity, R_eit is earth's spheroid major axis radius;

3rd step, points to the course angle ψ of impact point with following formulae discovery boresight_b:

As λ > λ₁and L > L₁ψ_b=σ

As λ > λ₁and L < L₁ψ_b=180 ° of-σ

As λ < λ₁and L < L₁ψ_b=180 ° of+σ

As λ < λ₁and L > L₁ψ_b=-σ

As λ=λ₁and L > L₁ψ_b=0 °

As λ=λ₁and L < L₁ψ_b=180 °

As λ < λ₁and L=L₁ψ_b=-90 °

As λ > λ₁and L=L₁ψ_b=90 °

4th step, with following formulae discovery boresight and horizontal plane angle δ:

$\mathrm{\&delta;}=\arcsin \frac{|h-h_1|}{S}$

5th step, points to the pitching angle theta of impact point with following formulae discovery boresight_b:

As h > h₁θ_b=δ

As h < h₁θ_b=-δ

6th step, computed geographical coordinates is to the attitude matrix of carrier aircraft coordinate system

$C_A^n=\left[\begin{array}{ccc}\cos {\mathrm{\&gamma;}}_A\cos {\mathrm{\&psi;}}_A+\sin {\mathrm{\&gamma;}}_A\sin {\mathrm{\&psi;}}_A\sin {\mathrm{\&theta;}}_A& \sin {\mathrm{\&psi;}}_A\cos {\mathrm{\&theta;}}_A& \sin {\mathrm{\&gamma;}}_A\cos {\mathrm{\&psi;}}_A-\cos {\mathrm{\&gamma;}}_A\sin {\mathrm{\&psi;}}_A\sin {\mathrm{\&theta;}}_A\\ -\cos {\mathrm{\&gamma;}}_A\sin {\mathrm{\&psi;}}_A+\sin {\mathrm{\&gamma;}}_A\cos {\mathrm{\&psi;}}_A\sin {\mathrm{\&theta;}}_A& \cos {\mathrm{\&psi;}}_A\cos {\mathrm{\&theta;}}_A& -\sin {\mathrm{\&gamma;}}_A\sin {\mathrm{\&psi;}}_A-\cos {\mathrm{\&gamma;}}_A\cos {\mathrm{\&psi;}}_A\sin {\mathrm{\&theta;}}_A\\ -\sin {\mathrm{\&gamma;}}_A\cos {\mathrm{\&theta;}}_A& \sin {\mathrm{\&theta;}}_A& \cos {\mathrm{\&gamma;}}_A\cos {\mathrm{\&theta;}}_A\end{array}\right]$

7th step, calculates the attitude matrix of boresight to geographic coordinate system

$C_n^b=\left[\begin{array}{ccc}\cos {\mathrm{\&psi;}}_b& -\sin {\mathrm{\&psi;}}_b& 0\\ \sin {\mathrm{\&psi;}}_b\cos {\mathrm{\&theta;}}_b& \cos {\mathrm{\&psi;}}_b\cos {\mathrm{\&theta;}}_b& \sin {\mathrm{\&theta;}}_b\\ -\sin {\mathrm{\&psi;}}_b\sin {\mathrm{\&theta;}}_b& -\cos {\mathrm{\&psi;}}_b\sin {\mathrm{\&theta;}}_b& \cos {\mathrm{\&theta;}}_b\end{array}\right]$

8th step, calculates the attitude matrix of boresight to carrier aircraft coordinate system

$C_A^b=C_n^b*C_A^n=\left[\begin{array}{ccc}{C}_1\left(\mathrm{1,1}\right)& C_1\left(\mathrm{2,1}\right)& C_1\left(\mathrm{3,1}\right)\\ C_1\left(\mathrm{1,2}\right)& C_1\left(\mathrm{2,2}\right)& C_1\left(\mathrm{3,2}\right)\\ C_1\left(\mathrm{1,3}\right)& C_1\left(\mathrm{2,3}\right)& C_1\left(\mathrm{3,3}\right)\end{array}\right]$

In formula, C₁(i, j) and (i=1,2,3 j=1,2,3) are matrixesevery element;

9th step, calculates the angle of pitch β of carrier aircraft optical axis stable turntable, azimuth angle alpha and roll angle χ:

9.1 with the angle of pitch β of following formulae discovery carrier aircraft optical axis stable turntable, with reference to roll angle γ_cwith reference azimuth ψ_c:

β＝arcsinC₁(3，2)

${\mathrm{\&gamma;}}_C=\arctan (-\frac{C_1\left(\mathrm{3,1}\right)}{C_1\left(\mathrm{3,3}\right)})$

${\mathrm{\&psi;}}_C=\arctan \left(\frac{C_1\left(\mathrm{1,2}\right)}{C_1\left(\mathrm{2,2}\right)}\right)$

9.2 calculate carrier aircraft optical axis stable turntable azimuth angle alpha by following discrimination formula:

Work as C₁(2,2) → 0 and C₁(1,2) > 0 α=90 °

Work as C₁(2,2) → 0 and C₁(1,2) < 0 α=-90 °

Work as C₁(2,2) > 0 α=ψ_c

Work as C₁(2,2) < 0 and C₁(1,2) > 0 α=ψ_c+ 180 °

Work as C₁(2,2) < 0 and C₁(1,2) < 0 α=ψ_c-180 °

9.3 calculate carrier aircraft optical axis stable turntable roll angle χ by following discrimination formula:

Work as C₁(3,3) > 0 χ=γ_c

Work as C₁(3,3) < 0 and γ_c> 0 χ=γ_c-180 °

Work as C₁(3,3) < 0 and γ_c< 0 χ=γ_c+ 180 °

Tenth step, is transferred to servo control unit by the azimuth angle alpha, angle of pitch β, the roll angle χ that calculate the carrier aircraft optical axis stable turntable obtained;

11 step, repeats the first step to the tenth step, until superior system terminates after sending geographic tracking END instruction.

Overall technology effect of the present invention is presented as following four aspects.

(1) the present invention utilize carrier and target geography information and in conjunction with attitude of carrier, according to space geometry algorithm, this angular metric, relative to the space angle of carrier coordinate system, is then given servo control unit, is completed the geographic tracking to target by real-time calculating carrier boresight.Therefore desirable in target scene, or background environment and object spectral characteristic poor contrast, even under target such as to be blocked at the situation, the inventive method can to the stable tracking of target Continuous.Thus the photoelectricity investigation significantly improving system is searched with ability with target, plays inertial navigation further and surely takes aim at the information fusion of control, the effect of cooperation.

(2) the bright feature that there is optical axis and overlap with the axes of inertia of we, so the spatial attitude angle of boresight and the spatial attitude angle of stable turntable completely the same, so controlling essence to the spatial attitude of turntable is exactly control the spatial attitude of boresight, thus passes through to ensure the fine sight of boresight to target of the accurate control realization to stable turntable.

(3) the present invention only uses space geometry algorithm, then through a matrix computations, just can complete calculating to the space vector angle of tracking target boresight.Therefore simple operating steps of the present invention, data calculated amount is little, requires lower to system hardware resources.Can in the system of multiple weapon platform graft application, there is versatility.

(4) the present invention makes full use of geography information and Inertia information calculates in real time, not only for photoelectronic reconnaissance and Target Tracking System, and be applicable to the attack weapon system needing geographical information acquisition trace command, such as, for seeker provides a kind of target guiding method.

Accompanying drawing explanation

Fig. 1 is the operational flowchart of geographic tracking method of the present invention.

Fig. 2 is the relation schematic diagram between carrier aircraft, optical axis stable turntable, geographic coordinate system.

Fig. 3 is geographic tracking model space geometric relationship schematic diagram.

Embodiment

Below in conjunction with accompanying drawing and preferred embodiment, the present invention is described in further detail.

The preferred embodiment of geographic tracking method of the present invention is used for the UAV system photodetection/tracker of following the tracks of certain fixed target.This system comprises optical axis stable turntable, inertial navigation unit, servo control unit, information process unit.Wherein, the optical axis on optical axis stable turntable overlaps with the axes of inertia of inertial navigation unit, and information process unit comprises the computing machine that geographic tracking module is housed.This method is computer implemented by information process unit.Parameter ellipticity e and earth's spheroid major axis radius R has been deposited in advance in the hard disk of computing machine_e.In unmanned plane during flying process, if airborne photoelectric detection/tracker locks a certain target, and photodetection/tracker receives superior system when sending geographic tracking instruction, and the flow process according to Fig. 1 is completed following operating process by geographic tracking module.

The first step, gathers the impact point data (λ, L, h) of target locating set output and the data (λ of current carrier aircraft location point₁, L₁, h₁, ψ_a, θ_a, γ_a, S).Wherein λ, L, h are the longitude of impact point, latitude and height respectively; λ₁, L₁, h₁the current longitude of carrier aircraft, latitude and height respectively, ψ_a, θ_a, γ_abe the current course angle of carrier aircraft under geographic coordinate system, the angle of pitch and roll angle respectively, S is the distance of current carrier aircraft to impact point.

According to Fig. 2, geographic coordinate system n is defined as: initial point O is the earth point place at carrier aircraft place, and X-axis points to direction, due east from initial point O, and Y-axis points to direct north from initial point O, and Z axis points to zenith perpendicular to ground, and X-axis, Y-axis and Z axis form right-handed coordinate system.Carrier aircraft coordinate system A is defined as: initial point O is aircraft barycenter, and X-axis is pointed to right along carrier aircraft transverse axis, Y-axis points to head along the carrier aircraft longitudinal axis, and Z axis points to machine by ventral and carries on the back in longitudinal symmetrical plane, and X-axis, Y-axis and Z axis form right-handed coordinate system.

Carrier aircraft course angle ψ_abe defined as: carrier aircraft is around the angle that Z axis rotates under geographic coordinate system, and regulation is just rotating to be to the right; Carrier aircraft pitching angle theta_abe defined as: carrier aircraft is around the angle that X-axis rotates under geographic coordinate system, and regulation rotates up as just; Carrier aircraft roll angle γ_abe defined as: carrier aircraft is around the angle that Y-axis rotates under geographic coordinate system, and regulation is rotated counterclockwise as just.

In this preferred embodiment, current goal point data is: (λ, L, h)=(108.8929,34.1504,5.2)

Current carrier aircraft location point data are:

(λ₁，L₁，h₁，ψ_A，θ_A，γ_A，S)＝(108.8552，34.13，1235.3，3.49221°，1.03811°，-0.0002°，4320.5)

Second step, according to longitude λ, λ of impact point and carrier aircraft location point₁with latitude L, L₁, in surface level projects, projected to the north orientation angle σ of impact point projection vector line segment by carrier aircraft with following formulae discovery carrier aircraft and impact point.

$\mathrm{\&sigma;}=\arctan \frac{|\mathrm{\&lambda;}-{\mathrm{\&lambda;}}_1|\&times;R_M\&times;\cos L_1}{|L-L_1|\&times;R_N}$

R_M＝R_e(1-2e+3esin²L₁)

R_N＝R_e(1+esin²L₁)

$e=\frac{1}{298.257}$

R_e＝6378137

Wherein, R_mthe radius of curvature of meridian of carrier aircraft current location, R_nbe the radius of curvature in prime vertical of carrier aircraft current location, e is the ellipticity of the earth, R_eit is the major axis radius of the earth.

Fig. 3 is that in this preferred embodiment, carrier aircraft and Target space position relation and space geometry calculate schematic diagram.Under this figure is based upon geographic coordinate system, F represents current carrier aircraft location point, T represents impact point, M and N is F point and the projection in the horizontal plane of T point respectively, NK represents line segment parallel with Y-axis under geographic coordinate system, so some M, N and K form the right-angle triangle Δ MNK on surface level, JT is the line segment parallel with MN.North orientation angle σ is the angle of line segment MN and line segment NK, i.e. ∠ MNK in the drawings.

3rd step, according to the result of calculation of second step, and the longitude λ of combining target point and the longitude λ of carrier aircraft location point₁, calculate by following discrimination formula the course angle ψ that boresight points to impact point_b.

As λ > λ₁and L > L₁ψ_b=σ

As λ > λ₁and L < L₁ψ_b=180 ° of-σ

As λ < λ₁and L < L₁ψ_b=180 ° of+σ

As λ < λ₁and L > L₁ψ_b=-σ

As λ=λ₁and L > L₁ψ_b=0 °

As λ=λ₁and L < L₁ψ_b=180 °

As λ < λ₁and L=L₁ψ_b=-90 °

As λ > λ₁and L=L₁ψ_b=90 °

Boresight points to the position angle ψ of impact point_bbe defined as: the boresight aimed at the mark a little is around the angle that Z axis rotates under geographic coordinate system, and regulation is just rotating to be to the right.

In the preferred embodiment, calculate by the 3rd step the course angle ψ that boresight points to impact point_bbe:

ψ_b＝56.70638°

4th step, according to height h, h of impact point and carrier aircraft location point₁and the distance S between carrier aircraft to impact point, with following formulae discovery boresight and horizontal plane angle δ:

$\mathrm{\&delta;}=\arcsin \frac{|h-h_1|}{S}$

In figure 3, line segment FM represents carrier aircraft location point height h, and line segment TN represents impact point height h₁, line segment FT is the distance S between carrier aircraft to impact point.Boresight and horizontal plane angle δ are the angle of line segment FT and line segment JT, i.e. ∠ FTJ in the drawings.

5th step, according to four-step calculation result, and height h, h of combining target point and carrier aircraft location point₁, calculate by following discrimination formula the pitching angle theta that boresight points to impact point_b:

As h > h₁θ_b=δ

As h < h₁θ_b=-δ

Boresight points to the pitching angle theta of impact point_bbe defined as: the angle that the boresight aimed at the mark under geographic coordinate system a little rotates around X-axis, regulation rotates up as just.

In this preferred embodiment, calculate by the 5th step the pitching angle theta that boresight points to impact point_bbe:

θ_b＝-16.54163°

6th step, according to the course angle ψ of carrier aircraft location point_a, pitching angle theta_awith roll angle γ_a, the attitude matrix of carrier aircraft coordinate system is tied to following formulae discovery geographic coordinate

$C_A^n=\left[\begin{array}{ccc}\cos {\mathrm{\&gamma;}}_A\cos {\mathrm{\&psi;}}_A+\sin {\mathrm{\&gamma;}}_A\sin {\mathrm{\&psi;}}_A\sin {\mathrm{\&theta;}}_A& \sin {\mathrm{\&psi;}}_A\cos {\mathrm{\&theta;}}_A& \sin {\mathrm{\&gamma;}}_A\cos {\mathrm{\&psi;}}_A-\cos {\mathrm{\&gamma;}}_A\sin {\mathrm{\&psi;}}_A\sin {\mathrm{\&theta;}}_A\\ -\cos {\mathrm{\&gamma;}}_A\sin {\mathrm{\&psi;}}_A+\sin {\mathrm{\&gamma;}}_A\cos {\mathrm{\&psi;}}_A\sin {\mathrm{\&theta;}}_A& \cos {\mathrm{\&psi;}}_A\cos {\mathrm{\&theta;}}_A& -\sin {\mathrm{\&gamma;}}_A\sin {\mathrm{\&psi;}}_A-\cos {\mathrm{\&gamma;}}_A\cos {\mathrm{\&psi;}}_A\sin {\mathrm{\&theta;}}_A\\ -\sin {\mathrm{\&gamma;}}_A\cos {\mathrm{\&theta;}}_A& \sin {\mathrm{\&theta;}}_A& \cos {\mathrm{\&gamma;}}_A\cos {\mathrm{\&theta;}}_A\end{array}\right]$

7th step, according to the result of calculation of the 3rd step and the 5th step, with the attitude matrix of following formulae discovery boresight to geographic coordinate system

$C_n^b=\left[\begin{array}{ccc}\cos {\mathrm{\&psi;}}_b& -\sin {\mathrm{\&psi;}}_b& 0\\ \sin {\mathrm{\&psi;}}_b\cos {\mathrm{\&theta;}}_b& \cos {\mathrm{\&psi;}}_b\cos {\mathrm{\&theta;}}_b& \sin {\mathrm{\&theta;}}_b\\ -\sin {\mathrm{\&psi;}}_b\sin {\mathrm{\&theta;}}_b& -\cos {\mathrm{\&psi;}}_b\sin {\mathrm{\&theta;}}_b& \cos {\mathrm{\&theta;}}_b\end{array}\right]$

8th step, according to the result of calculation of the 6th step and the 7th step, with the attitude matrix of following formulae discovery boresight to carrier aircraft coordinate system

$C_A^b=C_n^b*C_A^n=\left[\begin{array}{ccc}{C}_1\left(\mathrm{1,1}\right)& C_1\left(\mathrm{2,1}\right)& C_1\left(\mathrm{3,1}\right)\\ C_1\left(\mathrm{1,2}\right)& C_1\left(\mathrm{2,2}\right)& C_1\left(\mathrm{3,2}\right)\\ C_1\left(\mathrm{1,3}\right)& C_1\left(\mathrm{2,3}\right)& C_1\left(\mathrm{3,3}\right)\end{array}\right]$

In formula, C₁(i, j) and (i=1,2,3 j=1,2,3) are matrixesevery element.

9th step, calculates the angle of pitch β of carrier aircraft optical axis stable turntable, azimuth angle alpha and roll angle χ.

9.1 calculate attitude matrix according to the 8th stepthe C obtained₁(3,2), C₁(3,1), C₁(3,3), C₁(1,2) and C₁(2,2), with the angle of pitch β of following formulae discovery carrier aircraft optical axis stable turntable, with reference to roll angle γ_cwith reference azimuth ψ_c

β＝arcsinC₁(3，2)

${\mathrm{\&gamma;}}_C=\arctan (-\frac{C_1\left(\mathrm{3,1}\right)}{C_1\left(\mathrm{3,3}\right)})$

${\mathrm{\&psi;}}_C=\arctan \left(\frac{C_1\left(\mathrm{1,2}\right)}{C_1\left(\mathrm{2,2}\right)}\right)$

The optical axis stable turntable coordinate system b of photodetection/tracker is defined as: initial point O is optical axis stable rotation of rotary table center, X-axis is its main horizontal line, namely pitch axis is rotated, Y-axis points to run-home along the boresight of optical axis stable turntable, namely roll axle is rotated, Z axis perpendicular to XY plane and point to zenith, i.e. rotational orientation axle, X-axis, Y-axis and Z axis form right-handed coordinate system.

Carrier aircraft optical axis stable turntable angle of pitch β is defined as: optical axis stable turntable is around the angle that X-axis rotates under carrier aircraft coordinate system, and regulation rotates up as just.

In this preferred embodiment, the data calculated by the 8th step are:

C₁(3，2)＝-0.2950682

C₁(3，1)＝0.01450774

C₁(3，3)＝0.955366

C₁(1，2)＝0.7677324

C₁(2，2)＝0.5687895

Calculate accordingly:

β＝-17.16163°

γ_C＝-0.8699°

ψ_C＝53.46638°

The 9.2 reference azimuth ψ calculated according to the 9.1st step_c, and in conjunction with attitude matrixin C₁(1,2) and C₁(2,2) two elements, calculate carrier aircraft optical axis stable turntable azimuth angle alpha by following discrimination formula:

Work as C₁(2,2) → 0 and C₁(1,2) > 0 α=90 °

Work as C₁(2,2) → 0 and C₁(1,2) < 0 α=-90 °

Work as C₁(2,2) > 0 α=ψ_c

Work as C₁(2,2) < 0 and C₁(1,2) > 0 α=ψ_c+ 180 °

Work as C₁(2,2) < 0 and C₁(1,2) < 0 α=ψ_c-180 °

Carrier aircraft optical axis stable turntable azimuth angle alpha is defined as: optical axis stable turntable is around the angle that Z axis rotates under carrier aircraft coordinate system, and regulation is just rotating to be to the right;

In this preferred embodiment, α=53.46638 °

The 9.3 reference roll angle γ calculated according to the 9.1st step_c, and in conjunction with attitude matrixin C₁(3,3), calculate carrier aircraft optical axis stable turntable roll angle χ by following discrimination formula:

Work as C₁(3,3) > 0 χ=γ_c

Work as C₁(3,3) < 0 and γ_c> 0 χ=γ_c-180 °

Work as C₁(3,3) < 0 and γ_c< 0 χ=γ_c+ 180 °

Carrier aircraft optical axis stable turntable roll angle χ is defined as: optical axis stable turntable is around the angle that Y-axis rotates under carrier aircraft coordinate system, and regulation is rotated counterclockwise as just.

In this preferred embodiment, χ=-0.8699 °.

Tenth step, is transferred to servo control unit carries out Angle Position servocontrol by the carrier aircraft optical axis stable turntable azimuth angle alpha obtained, angle of pitch β, roll angle χ.

11 step, repeats the first step to the tenth step, until superior system terminates after sending geographic tracking END instruction.

Claims (1)

1. based on the geographic tracking method that optical axis overlaps with the axes of inertia, it is characterized in that: the method comprises following operation steps:

The first step, gathers the impact point data (λ, L, h) of target locating set output and the data (λ of current carrier aircraft location point₁, L₁, h₁, ψ_a, θ_a, γ_a, S), wherein λ, L, h are the longitude of impact point, latitude and height respectively; λ₁, L₁, h₁the current longitude of carrier aircraft, latitude and height respectively, ψ_a, θ_a, γ_abe the current course angle of carrier aircraft under geographic coordinate system, the angle of pitch and roll angle respectively, S is the distance of current carrier aircraft to impact point;

Second step, is projected to the north orientation angle σ of impact point projection vector line segment in surface level projects by carrier aircraft with following formulae discovery carrier aircraft and impact point:

R_M＝R_e(1-2e+3esin²L₁)

R_N＝R_e(1+esin²L₁)

Wherein, R_mthe radius of curvature of meridian of carrier aircraft current location, R_nbe the radius of curvature in prime vertical of carrier aircraft current location, e is ellipticity, R_eit is earth's spheroid major axis radius;

3rd step, points to the course angle ψ of impact point with following formulae discovery boresight_b:

As λ > λ₁and L > L₁ψ_b=σ

As λ > λ₁and L < L₁ψ_b=180 ° of-σ

As λ < λ₁and L < L₁ψ_b=180 ° of+σ

As λ < λ₁and L > L₁ψ_b=-σ

As λ=λ₁and L > L₁ψ_b=0 °

As λ=λ₁and L < L₁ψ_b=180 °

As λ < λ₁and L=L₁ψ_b=-90 °

As λ > λ₁and L=L₁ψ_b=90 °

4th step, with following formulae discovery boresight and horizontal plane angle δ:

5th step, points to the pitching angle theta of impact point with following formulae discovery boresight_b:

As h > h₁θ_b=δ

As h < h₁θ_b=-δ

6th step, computed geographical coordinates is to the attitude matrix of carrier aircraft coordinate system

7th step, calculates the attitude matrix of boresight to geographic coordinate system

8th step, calculates the attitude matrix of boresight to carrier aircraft coordinate system

In formula, C₁(i, j) and i=1,2,3, j=1,2,3 is matrixesevery element;

9th step, calculates the angle of pitch β of carrier aircraft optical axis stable turntable, azimuth angle alpha and roll angle χ:

9.1 with the angle of pitch β of following formulae discovery carrier aircraft optical axis stable turntable, with reference to roll angle γ_cwith reference azimuth ψ_c:

β＝arcsin C₁(3，2)

9.2 calculate carrier aircraft optical axis stable turntable azimuth angle alpha by following discrimination formula:

Work as C₁(2,2) → 0 and C₁(1,2) > 0 α=90 °

Work as C₁(2,2) → 0 and C₁(1,2) < 0 α=-90 °

Work as C₁(2,2) > 0 α=ψ_c

Work as C₁(2,2) < 0 and C₁(1,2) > 0 α=ψ_c+ 180 °

Work as C₁(2,2) < 0 and C₁(1,2) < 0 α=ψ_c-180 °

9.3 calculate carrier aircraft optical axis stable turntable roll angle χ by following discrimination formula:

Work as C₁(3,3) > 0 χ=γ_c

Work as C₁(3,3) < 0 and γ_c> 0 χ=γ_c-180 °

Work as C₁(3,3) < 0 and γ_c< 0 χ=γ_c+ 180 °

Tenth step, is transferred to servo control unit by the azimuth angle alpha, angle of pitch β, the roll angle χ that calculate the carrier aircraft optical axis stable turntable obtained;

11 step, repeats the first step to the tenth step, until superior system terminates after sending geographic tracking END instruction.