CN102706360B - Method utilizing optical flow sensors and rate gyroscope to estimate state of air vehicle - Google Patents

Abstract

The invention relates to a method utilizing optical flow sensors and a rate gyroscope to estimate the state of an air vehicle. The method comprises the following four steps of: step 1, aiming at the air vehicle needing to install the optical flow sensors, establishing a linearized-perturbation kinematical equation; step 2, arranging five optical flow sensors onto the air vehicle in a multipoint mode, causing the distance among the sensors to be far as much as possible, causing the sensors to direct different directions; step 3, establishing a measurement equation of the optical flow sensors, establishing a measurement equation of the rate gyroscope, and forming a measurement equation of multiple sensors of optical flow and inertia navigation of a system; and step 4, estimating the flight state of the air vehicle with UKF, namely unscented kalman filters. The optical flow sensor has small size, light weight, small power consumption and low cost, is convenient to be installed on small air vehicles, and does not externally radiate electromagnetic signals. The stealthiness of the air vehicle is increased.

Description

A kind of method of utilizing light stream sensor and rate gyro to estimate flight state

(1) technical field:

The measurement and the estimation technique field that the invention belongs to small aircraft (Miniature aerial vehicles, MAVs) attitude, flying speed and height, be specifically related to a kind of light stream sensor and the method for rate gyro to MAV state estimation utilized.

(2) background technology:

Aircraft mainly relies on forward-looking radar, radar altimeter and climb meter to measure terrain clearance and rising or falling speed, and for small aircraft, it is too heavy that laser range finder (Laser Rangefinders, LRF) and radar all seem.SICKLMS291 is a typical laser range finder, is generally used for robot field, and its quality is approximately 4.5 kilograms.For push-button aircraft (Unmanned Aerial Vehicle, UAV) the minimum synthetic-aperture radar on may be the miniSAR that manufacture in sub-laboratory, the U.S. Holy Land (Sandia National Labs), its quality is about 4～5 kilograms, so heavy equipment has increased the weight and volume of unmanned plane, has reduced its flying power and load capacity.

Light stream sensor mass is little, only have 10 grams of left and right, receive completely passively extraneous light, radiationless, with respect to radar altimeter, have advantages of that quality is little, good concealment, except the flying speed of aircraft, flying height, rate of pitch, this method can also estimate other flight informations such as the angle of attack, the angle of pitch, rising or falling speed of aircraft, and these information are conducive to help MAV to complete the particular flight tasks such as detection, the disaster relief.

(3) summary of the invention:

1, object: the object of this invention is to provide a kind of method of utilizing light stream sensor and rate gyro to estimate flight state, it uses 5 light stream sensors and 1 cover three axle rate gyros, volume is little, lightweight, power consumption is little, cost is low, be convenient to mounting arrangements on small aircraft, external electromagnetic radiation signal, has improved the disguise of aircraft.

2, technical scheme: insect is when mobile, the luminance patterns of surrounding environment forms a series of continually varying images on retina, this a series of continually varying information is " flowing through " retina constantly, seems a kind of " stream " of light, therefore claim that the apparent motion of this brightness of image pattern is light stream.Some external laboratory, developed the physical prototyping of light stream sensor, and utilize light stream sensor to realize the automatic obstacle avoiding of unmanned vehicle, constant-level flight, automatic Landing, wind estimation, target detection and hovering, these technology will have very important using value at aspects such as detection, the disaster relief.

According to the geometric relationship shown in the definition of light stream and Fig. 1, can show that the expression formula of light stream is:

$f=\frac{v{\cos }^2\mathrm{\θ}}{h}+\mathrm{\ω}---\left(1\right)$

In formula, f is light stream (1/s), and v is the horizontal velocity (m/s) of light stream sensor, and h is the height (m) on light stream sensor distance ground, θ is the angle (rad) of optical axis and vertical, and ω is the rotational speed (rad/s) of light stream sensor.

By formula (1), can be found out, the measured value of light stream is relevant with speed coupling with attitude, the height of light stream sensor, simultaneously light stream sensor have that volume is little, lightweight, power consumption is little, cost is low, feature that can networking, so consider a plurality of light stream sensors to connect firmly on aircraft, in conjunction with inertial navigation device---rate gyro, utilize the information fusion technology of multisensor, realize the estimation to attitude of flight vehicle information.Light stream sensor is arranged as shown in Figure 2.

A kind of method of utilizing light stream sensor and rate gyro to estimate flight state of the present invention, the method concrete steps are as follows:

Step 1: for the aircraft that light stream sensor need to be installed, set up its linearize disturbance motion equation;

$\stackrel{\·}{X}=\mathrm{AX}+\mathrm{Bu}+w\left(t\right)---\left(2\right)$

Here, X=[V _tα q h β θ ψ c p r ψ γ] ^t, $u={\left[\begin{array}{ccc}{\mathrm{\δ}}_{\mathrm{th}}& {\mathrm{\δ}}_{\mathrm{ev}}^R& {\mathrm{\δ}}_{\mathrm{ev}}^L\end{array}\right]}^T$

V _t: flight speed (m/s)

α, β: the angle of attack and yaw angle (rad)

γ, ψ: roll angle, the angle of pitch and crab angle (rad)

R, q, p: angular velocity in roll, rate of pitch and yaw rate (rad/sec)

H: flying height (m)

θ, ψ _c: trajectory tilt angle and trajectory deflection angle (rad)

δ _th: throttle push rod angle (rad)

left rudder drift angle and right standard rudder drift angle (rad)

W (t): white-noise process, E[w (t)]=0, E[w (t) w ^t(τ)]=q _wδ (t-τ), q _wvariance intensity battle array for w (t).

Step 2: 5 light stream sensor multiple spots are arranged on aircraft, and the in the situation that of permission in space, the distance between each sensor will be tried one's best far, and points to different directions, does like this and is conducive to improve follow-up estimated accuracy;

Wherein, " multiple spot layout " refers to, light stream sensor will be arranged on the diverse location of aircraft, and exemplary position is head, centre, afterbody and wingtip; " distance will be tried one's best far away " refers to, be arranged on the light stream sensor of head, afterbody or wingtip, in the situation that not affecting other airborne equipment, to try one's best near body foremost, rearmost end or side, so just guaranteed that distance between head, afterbody and wingtip light stream sensor is as far as possible greatly.

Step 3: according to each light stream sensor in carry-on installation site and direction, set up the measurement equation of light stream sensor, utilize inertial navigation device---the rate gyro carrying on aircraft, or three axle rate gyros are installed on aircraft in addition, set up the measurement equation of rate gyro, with together with the measurement equation of light stream sensor, the light stream of construction system and inertial navigation Multisensor Measurement equation;

In fact, a light stream sensor can be measured two light stream components on orthogonal directions simultaneously, and it measures output and can be designated as

$f=\left(\begin{array}{c}{f}_x\\ f_y\end{array}\right)---\left(3\right)$

And aircraft rate of pitch can be measured by rate gyro, therefore system measurements equation is:

$Z={\left(\begin{array}{ccccc}{f}_1^T& f_2^T& ...& f_n^T& {\mathrm{\ω}}^T\end{array}\right)}^T+v\left(t\right)---\left(4\right)$

In formula, v (t) is measurement noise, supposes that it is that average is 0 white noise, i.e. E[v (t)]=0, and E[v (t) v ^t(τ)]=r _vδ (t-τ), r _vvariance intensity battle array for v (t).

Step 4: the state of flight of aircraft is estimated with UKF (Unscented Kalman Filter, Unscented kalman filtering).

3, advantage and effect: the present invention is a kind of method of utilizing light stream sensor and rate gyro to estimate flight state, its advantage is: (1) measuring sensor volume is little, lightweight, power consumption is little, cost is low, is convenient to arrange on aircraft, installs and uses; (2) the not external electromagnetic radiation signal of measuring sensor, is conducive to aircraft and completes disguised task; (3), except the flying speed of aircraft, flying height, this method can also estimate other flight informations such as the attitude angle of aircraft and attitude angular velocity.

(4) accompanying drawing explanation:

Fig. 1 is light stream sensor measurement graph of a relation

In Fig. 1, v is the horizontal velocity (rad/s) of light stream sensor, and h is the height (m) on light stream sensor distance ground, and θ is the angle (rad) of optical axis and vertical, and ω is the rotational speed (rad/s) of light stream sensor.

Fig. 2 is that light stream sensor is at carry-on arrangement schematic diagram

Fig. 3 is FB(flow block) of the present invention

Fig. 4 is the graph of a relation of each coordinate system

In Fig. 4, S _urepresent local coordinate system, S _brepresent body coordinate system, S _frepresent light stream sensor coordinate system.R _ubfor S _bwith respect to S _uposition vector, r _bffor S _fwith respect to S _bposition vector, r _uffor S _fwith respect to S _uposition vector.

Fig. 5 is simulation process block diagram

In Fig. 5, u is controlled quentity controlled variable, and x is quantity of state, and z is measuring value, for state estimation value.

Fig. 6 is that the measuring value of light stream sensor is at the Contrast on effect of UKF filtering front and back

Fig. 7 is that the measuring value of three-axis gyroscope is at the Contrast on effect of UKF filtering front and back

Fig. 8 is that UKF is to MAV speed, height and azimuthal estimation

V in Fig. 8 _tthe velocity magnitude (m/s) that represents MAV, h represents the flying height (m) of MAV, ψ _crepresent MAV flight azimuth (°)

Fig. 9 is the estimation of UKF to MAV aerodynamic condition

In Fig. 9, α represent the angle of attack (°), β represent yaw angle (°)

Figure 10 is the estimation of UKF to MAV flight attitude

In Figure 10, represent the angle of pitch (°), ψ represent crab angle (°), γ represent roll angle (°).

(5) embodiment:

Allocation plan schematic diagram according to the light stream sensor shown in the light stream sensor measurement graph of a relation shown in Fig. 1 and Fig. 2 on MAV, we have proposed a kind of method of utilizing light stream sensor and rate gyro to estimate flight state.Light stream sensor can record the even Optic flow information at rear of aircraft the place ahead, below, side, and these information provide foundation for estimate the residing surrounding enviroment of aircraft comprehensively.

In order to reduce the complexity of problem, simplify system mathematic model, make following hypothesis:

1) the quality texture of aircraft surrounding environment is mixed and disorderly, and light stream can be surveyed;

2) each light stream sensor can normally be worked, and their output contains measurement noise, but does not have full of prunes wild value;

3) field angle of light stream sensor is very little, and the information recording is the Optic flow information on camera lens axis;

Based on above hypothesis, see Fig. 3, the present invention is a kind of method of utilizing light stream sensor and rate gyro to estimate flight state, the method concrete steps are as follows:

Step 1: for the aircraft that light stream sensor need to be installed, set up its linearize disturbance motion equation;

The linearize disturbance motion equation of certain type MAV is:

$\stackrel{\·}{X}=\mathrm{AX}+\mathrm{Bu}+w\left(t\right)---\left(5\right)$

In formula, α is the angle of attack (rad), for the angle of pitch (rad), δ _zfor angle of rudder reflection (rad), h is body height of center of mass (m), and w (t) is white-noise process, E[w (t)]=0, E[w (t) w ^t(τ)]=q _wδ (t-τ), q _wvariance intensity battle array for w (t).

$A=\begin{array}{c}\left[\begin{array}{cccccccccccc}-0.239& 1.513& -9.81& 0& 0& 0& 0& 0& 0& 0& 0& 0\\ 0.055& -5.94& 0& 0.922& 0& 0& 0& 0& 0& 0& 0& 0\\ 0& 0.000& 0& 1& 0& 0& 0& 0& 0& 0& 0& 0\\ 0.017& -2.978& 0& -7.853& 0& 0& 0& 0& 0& 0& 0& 0\\ 0& -12& 12& 0& 0& 0& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& -0.072& 0.807& 0& 0.159& -0.987& 0& 0\\ 0& 0& 0& 0& 0& 0& 0& 0& 1& 0.161& 0& 0\\ 0& 0& 0& 0& 0& 0& 0& 0& 0& 1.013& 0& 0\\ 0& 0& 0& 0& 0& -115.511& 0& 0& -10.254& 1.445& 0& 0\\ 0& 0& 0& 0& 0& -15.179& 0& 0& -0.023& -0.233& 0& 0\\ 0& 0& 0& 0& 0& 0& 0& 0& 1& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& 0& 0& 0& 1& 0& 0\end{array}\right]\end{array}$

$B={\left[\begin{array}{cccccccccccc}6.741& -0.09& 0& 0& 0& 0& 0& 0& 0& 0& 0& 0\\ -0.006& -0.008& 0& -1.328& 0& 0& 0& 0& -0.93& -0.132& 0& 0\\ -0.006& -0.008& 0& -1.328& 0& 0& 0& 0& 0.93& 0.132& 0& 0\end{array}\right]}^T$

Step 2: 5 light stream sensor multiple spots are arranged on aircraft, and point to different directions;

Step 3: according to each light stream sensor in carry-on installation site and direction, set up the measurement equation of light stream sensor, utilize inertial navigation device---the rate gyro carrying on aircraft, or a rate gyro is installed on aircraft in addition, set up the measurement equation of rate gyro, with together with the measurement equation of light stream sensor, the light stream of construction system and inertial navigation Multisensor Measurement equation;

Before the measurement equation of derivation light stream sensor, first define several coordinate systems, as shown in Figure 4: local coordinate system (S _u): local coordinate system and the earth are connected, and are used for representing the absolute status of MAV.Select NED (North-East-Down, east northeast ground) coordinate system herein.This coordinate system and earth surface are connected, and x axle refers to north, and y axle refers to east, and z axle refers to ground.Ignore earth rotation, local coordinate system can be regarded inertial coordinates system as.It is mainly used to represent the absolute status of MAV, such as absolute velocity, absolute attitude etc.

Body coordinate system (S _b): it is upper that body coordinate system is connected in MAV, and its initial point is at the barycenter place of MAV, and x axle points to the place ahead of MAV, and z axle along the longitudinal plane of symmetry of MAV down, determine by the right-hand rule by y axle.

Light stream sensor coordinate system (S _f): light stream sensor coordinate system is connected on light stream sensor, and its initial point is at the focus place of camera lens, and z axle is outside optical axis direction points to, and x axle and y axle overlap with the light stream of two orthogonal directionss that record respectively.

So the transition matrix that is tied to body coordinate system by local coordinate is:

$L_{\mathrm{bu}}=L_x\left(\mathrm{\γ}\right)L_y\left(\mathrm{\θ}\right)L_z\left(\mathrm{\ψ}\right)$

$=\left(\begin{array}{ccc}\cos \mathrm{\θ}\cos \mathrm{\ψ}& \cos \mathrm{\θ}\sin \mathrm{\ψ}& -\sin \mathrm{\θ}\\ \sin \mathrm{\γ}\sin \mathrm{\θ}\cos \mathrm{\ψ}-\cos \mathrm{\γ}\sin \mathrm{\ψ}& \sin \mathrm{\γ}\sin \mathrm{\θ}\sin \mathrm{\ψ}+\cos \mathrm{\γ}\cos \mathrm{\ψ}& \sin \mathrm{\γ}\cos \mathrm{\θ}\\ \cos \mathrm{\γ}\sin \mathrm{\θ}\cos \mathrm{\ψ}+\sin \mathrm{\γ}\sin \mathrm{\ψ}& \cos \mathrm{\γ}\sin \mathrm{\θ}\sin \mathrm{\ψ}-\sin \mathrm{\γ}\cos \mathrm{\ψ}& \cos \mathrm{\γ}\cos \mathrm{\θ}\end{array}\right)---\left(6\right)$

By body coordinate system, to the transition matrix of light stream sensor coordinate system, be:

$L_{\mathrm{fb}}=L_y\left(\mathrm{\η}\right)L_x\left(\mathrm{\μ}\right)$

$=\left(\begin{array}{ccc}\cos \mathrm{\η}& \sin \mathrm{\η}\sin \mathrm{\μ}& -\sin \mathrm{\η}\cos \mathrm{\μ}\\ 0& \cos \mathrm{\μ}& \sin \mathrm{\μ}\\ \sin \mathrm{\μ}& -\cos \mathrm{\η}\sin \mathrm{\μ}& \cos \mathrm{\η}\cos \mathrm{\μ}\end{array}\right)---\left(7\right)$

Here, μ and η are the established angles of light stream sensor, they be light stream sensor coordinate system with respect to the Eulerian angle of body coordinate system, that is to say, by body coordinate system along x _baxle rotational angle μ, and then along y _baxle rotational angle η, can obtain light stream sensor coordinate system.

Therefore the transition matrix that, is tied to light stream sensor coordinate system by local coordinate is:

L _fu=L _fbL _bu (8)

Definition f _xand f _ythe light stream component of two orthogonal directionss that light stream sensor records, they are respectively along x _fand y _fdirection, so measurement equation can be write as:

$f=\left(\begin{array}{c}{f}_x\\ f_y\end{array}\right)=\left(\begin{array}{c}\frac{{\left(V_f\right)}_{f,x}}{d_{\mathrm{fg}}}+{\left({\mathrm{\ω}}_f\right)}_{f,y}\\ \frac{{\left(V_f\right)}_{f,y}}{d_{\mathrm{fg}}}+{\left({\mathrm{\ω}}_f\right)}_{f,x}\end{array}\right)---\left(9\right)$

Here, V _fand ω _frespectively velocity and the angular velocity vector of light stream sensor, subscript _{f, x}with _{f, y}represent respectively x component and y component in light stream sensor coordinate system.D _fgfor the focus of light stream sensor is along z _fdistance to ground.Make r _ubfor S _bwith respect to S _uposition vector, r _bffor S _fwith respect to S _bposition vector, so the velocity of light stream sensor can be expressed as:

$V_f=\frac{{\mathrm{dr}}_{\mathrm{uf}}}{\mathrm{dt}}=\frac{d}{\mathrm{dt}}(r_{\mathrm{ub}}+r_{\mathrm{bf}})=\frac{{\mathrm{dr}}_{\mathrm{ub}}}{\mathrm{dt}}+\frac{{\mathrm{dr}}_{\mathrm{bf}}}{\mathrm{dt}}---\left(10\right)$

Here, r _uffor S _fwith respect to S _uposition vector.

By velocity V _fto S _fprojection:

${\left(V_f\right)}_f=L_{\mathrm{fu}}\frac{d{\left(r_{\mathrm{ub}}\right)}_u}{\mathrm{dt}}+L_{\mathrm{fb}}(\frac{{d\left(r_{\mathrm{bf}}\right)}_b}{\mathrm{dt}}+{\left({\mathrm{\ω}}_b\right)}_b\×{\left(r_{\mathrm{bf}}\right)}_b)---\left(11\right)$

$=L_{\mathrm{fu}}\frac{d{\left(r_{\mathrm{ub}}\right)}_u}{\mathrm{dt}}+L_{\mathrm{fb}}{\left({\mathrm{\ω}}_b\right)}_b\×{\left(r_{\mathrm{bf}}\right)}_b$

It is pointed out that (ω _b) _bcan record by the three axle rate gyros that are arranged on MAV.

If z _fdirection vector be k _f, (k _f) _f=(0 0 1) ^t, by k _fto S _uprojection obtains:

(k _f) _u=L _uf(k _f) _f (12)

Z _fwith z _ubetween the cosine value of angle be (k _f) _{u, z}, so from light stream sensor focus to ground along z _fthe distance of direction is:

$d_{\mathrm{fg}}=\left|\frac{{\left(r_{\mathrm{uf}}\right)}_{u,z}}{{\left(k_f\right)}_{u,z}}\right|$

$=-\frac{{(r_{\mathrm{ub}}+r_{\mathrm{bf}})}_{u,z}}{{\left(k_f\right)}_{u,z}}---\left(13\right)$

$=-\frac{{\left(r_{\mathrm{ub}}\right)}_{u,z}{\left[L_{\mathrm{ub}}{\left(r_{\mathrm{bf}}\right)}_b\right]}_z}{{\left(k_f\right)}_{u,z}}$

And

(ω _f) _f＝(ω _b) _f

(14)

=L _fb(ω _b) _b

The measurement equation that formula (11), (13) and (14) substitutions (9) can be obtained to i light stream sensor, the total measurement equation of system is.

$Z={\left(\begin{array}{ccccc}{f}_1^T& f_2^T& ...& f_n^T& {\left({\mathrm{\ω}}_b\right)}_b^T\end{array}\right)}^T+v\left(t\right)---\left(15\right)$

Here, f _i(i=1,2 ..., n) represent the measured value of i light stream sensor.In formula, v (t) is measurement noise, supposes that it is that average is 0 white noise, i.e. E[v (t)]=0, and E[v (t) v ^t(τ)]=r _vδ (t-τ), r _vvariance intensity battle array for v (t)., because the number of light stream sensor is 5, can survey 10 light stream components herein, rate gyro can be surveyed 3 angular velocity components, therefore the dimension of total measurement equation is 13.

Step 4: select UKF to estimate the state of flight of aircraft.

According to UKF algorithmic rule, because system state dimension and system noise dimension are 12, the dimension of measurement equation is 13, therefore the dimension of augmented state vector is L=12+12+13=37, the sampling policy that Sigma is ordered is selected symmetric sampling, and its number is 2L+1=75.Other some starting condition have:

5 light stream sensors installation site and direction on MAV, with (x _by _bz _bμ η) form provides, and forms matrix M _{5 * 5}:

$M_{5\×5}=\left(\begin{array}{ccccc}0& 0& 0.1& 0& 0\\ 0.2& 0& 0.1& 0& 30/57.3\\ -0.2& 0& 0.1& 0& -30/57.3\\ 0& 0.5& 0.1& -30/57.3& 0\\ 0& -0.5& 0.1& 30/57.3& 0\end{array}\right)---\left(16\right)$

MAV kinetic model initial value:

x ₀=(11 0 0 0 13 5/57.3 0 5/57.3 0 0 5/57.3 5/57.3) ^T；

The initial value that UKF estimates:

${\mathrm{\χ}}_0^x={\left(\begin{array}{cccccccccccc}10& 10/57.3& 10/57.3& 0& 15& 0& 0& 0& 0& 0& 0& 0\end{array}\right)}^T.$

Press the block diagram of simulation process shown in Fig. 5, through numerical simulation, the metric data filter effect obtaining as shown in Figure 6.The output of light stream sensor contains noise, and these noise parts are directly from measurement noise, and another part secondary source is in process noise.As can be seen from Figure 6, UKF can suppress noise effectively, and Fig. 7 has illustrated this conclusion equally.

UKF to the state estimation effect of MAV as shown in Figure 8.At initial time, estimated value is that actual value exists certain deviation, but passing in time, this dwindles partially rapidly, final, and estimated value is consistent with actual value trend, and all converging on expectation value, this explanation UKF can estimate the speed of MAV, height and orientation quickly and effectively.Fig. 9 and Figure 10 have proved the validity that UKF estimates other state parameter of MAV.

Claims (2)

1. a method of utilizing light stream sensor and rate gyro to estimate flight state, is characterized in that: the method concrete steps are as follows:

Step 1: for the aircraft that light stream sensor need to be installed, set up its linearize disturbance motion equation;

$\stackrel{\·}{X}=\mathrm{AX}+\mathrm{Bu}+w\left(t\right)---\left(1\right)$

Here, $u={\left[\begin{array}{ccc}{\mathrm{\δ}}_{\mathrm{th}}& {\mathrm{\δ}}_{\mathrm{ev}}^R& {\mathrm{\δ}}_{\mathrm{ev}}^L\end{array}\right]}^T;$

V _t: flight speed (m/s)

α, β: the angle of attack and yaw angle (rad)

γ, ψ: roll angle, the angle of pitch and crab angle (rad)

R, q, p: angular velocity in roll, rate of pitch and yaw rate (rad/sec)

H: flying height (m)

θ, ψ _c: trajectory tilt angle and trajectory deflection angle (rad)

δ _th: throttle push rod angle (rad)

left rudder drift angle and right standard rudder drift angle (rad)

W (t): white-noise process, E[w (t)]=0, E[w (t) w ^t(τ)]=q _wδ (t-τ), q _wvariance intensity battle array for w (t);

Step 2: 5 light stream sensor multiple spots are arranged on aircraft, and the in the situation that of permission in space, the distance between each sensor is as far as possible far away, and points to different directions, does like this and is conducive to improve follow-up estimated accuracy;

Step 3: according to each light stream sensor in carry-on installation site and direction, set up the measurement equation of light stream sensor, utilize inertial navigation device---the rate gyro carrying on aircraft, or three axle rate gyros are installed on aircraft in addition, set up the measurement equation of rate gyro, with together with the measurement equation of light stream sensor, the light stream of construction system and inertial navigation Multisensor Measurement equation;

A light stream sensor can be measured two light stream components on orthogonal directions simultaneously, and it measures output and can be designated as

$f=\left(\begin{array}{c}{f}_x\\ f_y\end{array}\right)---\left(2\right)$

And aircraft rate of pitch can be measured by rate gyro, therefore system measurements equation is:

$Z={\left(\begin{array}{ccccc}{f}_1^T& f_2^T& \·\·\·& f_n^T& {\mathrm{\ω}}^T\end{array}\right)}^T+v\left(t\right)---\left(3\right)$

In formula, v (t) is measurement noise, supposes that it is that average is 0 white noise, i.e. E[v (t)]=0, and E[v (t) v ^t(τ)]=r _vδ (t-τ), r _vvariance intensity battle array for v (t);

Step 4: be that Unscented kalman filtering is estimated the state of flight of aircraft with UKF.

2. a kind of method of utilizing light stream sensor and rate gyro to estimate flight state according to claim 1, it is characterized in that: " distance is as far as possible far away " described in step 2 refers to the light stream sensor that is arranged on head, afterbody or wingtip, in the situation that not affecting other airborne equipment, will near body foremost, rearmost end or side, so just guaranteed that distance between head, afterbody and wingtip light stream sensor is as far as possible greatly.