(3), the content of the invention
The purpose of the present invention is to be based on high-precision optical fiber gyro inertial navigation system there is provided one kind when ship length is navigated, profit
The online adaptive scaling method of excitation is waved with wave with ship and systematic error parameter is produced, so as to improve navigation essence
Degree.
The object of the present invention is achieved like this:
The present invention comprises the following steps:
(1) initial alignment of systematic parameter is completed in laboratory, the related debugging of fiber-optic gyroscope strapdown inertial navigation system is completed
Work.
(2) fiber-optic gyroscope strapdown inertial navigation system is arranged on ship center, after preheating, starts to gather the navigation of IMU outputs
Data.
(3) determine initial state information to complete system coarse alignment according to IMU output, then determined according to coarse alignment
Attitude information pass through a series of strapdowns resolve completion system fine alignment.
(3) inertia device input/output model is set up, it is then determined that the state equation and observational equation of Kalman filter.
(4) during ship's navigation, ship does approximate oscillating motion with wave, makes full use of it to produce inertia device
Excitation.
(5) systematic error parameter is estimated and compensated again according to the Kalman filter equation of foundation, completes demarcation,
Update systematic error parameter.
Present invention additionally comprises following feature:
1st, the measurement model of inertia device
Due to the limitation of mechanical processing technique, mounting condition equal error factor, a systems of accelerometer system and top in real system
G systems of spiral shell system are not orthogonal coordinate system.According to accelerometer and the input/output relation of gyro, accelerometer and top are provided respectively
Linear calibration's model of spiral shell passage.
The input and output Mathematical Modeling of accelerometer passage is expressed as:
Aa=δ Kafb+δBa+wa
Wherein,Represent output of the accelerometer under a systems;Represent
Force vector is compared in input of the accelerometer under carrier coordinate system b systems;Accelerometer biasSystem
Random noiseKaFor:
Wherein, constant multiplier of the accelerometer on i directions δ Ki(i=x, y, z) is represented, the accelerometer i under a systems
The installation coefficient δ M between the measurement axle on the lower accelerometer j directions of measurement axle and b systems on directionijRepresent.
Laboratory Calibration is joined typically from high-accuracy turntable as benchmark, but in Kalman filter demarcation estimating system error
Do not have turntable benchmark in several processes, so new constraint must be made, a kind of conventional method is defined in the orthogonal seats of IMU
Mark system, i.e., under carrier coordinate system, XbAxle and XaDirection of principal axis is consistent, YbAxle is in O-XaYaIn plane, ZbAxle is true according to the right-hand rule
It is fixed.So δ KaIt will be expressed as again:
Similarly, the Mathematical Modeling of gyro passage is represented by:
Tg=δ Sgωb+δDg+wg
In formula,Represent output of three gyros under g systems;Represent
Input angle speed of three gyros under b systems;The zero of three gyros is inclinedThe random gyro of system
DriftSgFor:
In above formula, constant multiplier of the gyro on i directions δ Si(i=x, y, z) is represented, under g systems on gyro i directions
Measurement axle and b systems time gyro j directions on measurement axle between installation coefficient δ EijRepresent.
2nd, the state equation of Kalman filter is set up
Choose zero inclined, constant multiplier of velocity error, angular error, accelerometer and the gyro of inertial navigation system and system is installed
Number is used as the state variable filtered.It is made up of altogether 27 state parameters:
Wherein,
Wherein, δ VE、δVNWith δ VUSystem east orientation, north orientation and sky orientation speed error, δ φ are represented respectivelyE、δφNWith δ φUPoint
Not Biao Shi system east orientation, north orientation and day to attitude error.
Using " east, north, day " geographic coordinate system as navigational coordinate system, according to SINS velocity errors and attitude error equations,
Set up navigation error equation.Then it is described using linear first-order differential equation, draws the state equation of Kalman filter.
X is 27 dimension system state variableses, and F is 27 × 27 state matrixs for maintaining system, and G is the system noise square of 27 × 6 dimensions
Battle array, W maintains system noise vector for 6, and 6 dimension noise vectors can be expressed as with white noise:
The noise transfer matrix of system can be usedTo represent.Wherein,With(i, j=
1,2,3) the strapdown transition matrix of accelerometer and gyro is represented respectively.
The writeable component block matrix form of state-transition matrix, is represented with F:Wherein:
ReThe radius of the earth is represented, L represents the latitude in SINS locations, ωieRepresent earth rotation angular speed, VEAnd VNPoint
East orientation speed and north orientation speed that Biao Shi be in strapdown solution process.fE、fNAnd fURepresent respectively east orientation that accelerometer measures,
North orientation and day are to output specific force.With(i, j=1,2,3) represents the strapdown transition matrix of accelerometer and gyro respectively.ωb
For real gyro angular speed input value.
3rd, the observational equation for the Kalman filter set up:
During parameters revision, it is impossible to the accurate attitude error for obtaining carrier.And inertial navigation system is with Ship Swaying
Line is not present in calibration process to move, angular movement is only existed, now the speed of navigation calculation is zero, and position is constant.Pass through speed
Integration obtains the positional information of carrier, therefore using velocity error as observed quantity.
Z=[δ VE δVN δVU]T
Using IMU velocity error as observed quantity, then the measurement equation in filtering equations is represented by:
Z=HX+v
In above formula, H and v are respectively:
H=[diag { 111 } 03×24], v=[vx vy vz]T
Wherein, H represents observing matrix, and v, which is represented, measures noise.
4th, error parameter is compensated
Result is modified using the method based on Kalman filter estimating system error parameter, FOG- can be obtained
IMU systematic parameter High Definition Systems error parameter results.Afterwards, systematic parameter is compensated, is added to actual inertial navigation
In system, it is determined that whether the parameter of demarcation can improve the precision of system.
The method compensated according to systematic error parameter, inertial navigation system velocity error is arrived by the compensation of smart Calibration Simulation estimated result
In attitude error equations, velocity error and attitude error after being compensated, the error comparing result before and after output compensation.
The inventive method has the following advantages that:
1st, ship oscillating motion caused by wave is rationally utilized, realizes that the real-time adaptive of ship waves demarcation,
Ship is overcome when system length is navigated, the problem of inertia device demarcation is difficult.
2nd, on the premise of inertia device precision is not improved, it becomes possible to improve the stated accuracy of system, particularly in system
During long boat, in the case that systematic parameter easily changes, higher stated accuracy can be also realized.
3rd, compared with common peg model, simple to operate, low cost of the invention, fast convergence rate.
4th, the time interval that can be artificially set by system, can constantly update systematic parameter, and systematic parameter is mended
Repay.
5th, inertial navigation itself achieves that the self-recision to systematic parameter, it is not necessary to carry out extra manual hand manipulation or
Turntable rotates excitation.
6th, The present invention gives the specific steps that calibration algorithm is carried out inside inertial navigation system, enter according to inventive step and to it
Row simulating, verifying.There is important theory significance and construction value for the Auto-calibration of marine navigator parameter.
The explanation beneficial to the present invention:
MATLAB emulation experiments:
1st, simulated conditions are set
Under simulated conditions, it is assumed that fiber-optic gyroscope strapdown inertial navigation system be located at ship center position, inertia device relative to
Ship is static in itself, and IMU only does angular movement, without line motion, and has been completed initial alignment.
(1) optical fibre gyro inertial navigation system is under quiescent conditions:
System initial position:45.779 ° of north latitude, 126.671 ° of east longitude;
Terrestrial equator radius is set to:Re=6378137.0m;
Earth rotation angular speed:ωie=7.2921158 × 10-5m/s;
The acceleration of gravity of earth surface:G0=9.78049m/s2;
The turntable sampling time:T=0.01s;
(2) optical fibre gyro inertial navigation system with ship in the presence of wave when being in swinging condition, and parameter state is set
It is set to:
Rolling period:T=[8s 5s 5s]T;
Wave amplitude:ψmax=[14 ° 10 ° 10 °]T;
Initial phase:θ0=[0 ° 0 ° 0 °]T;
(3) FOG-IMU systematic errors parameter setting:
Initial misalignment:φ0=[0 ° 0 ° 0 °]T;
Accelerometer bias:δDa=[the μ g of 50 μ g, 50 μ g 50]T;
Accelerometer constant multiplier:δDa=[50ppm 50ppm 50ppm]T;
Accelerometer installs coefficient:Myx=Mzx=Mzy=50 ";
Gyro zero is inclined:Dg=[0.1 °/h, 0.1 °/h, 0.1 °/h]T;
Gyro installation coefficient:Dg=[50ppm 50ppm 50ppm]T;
Gyro scale factor error:Exy=Exz=Eyx=Eyz=Ezx=Ezy=50 ";
(4) in addition, state variable X initial value X0, initial covariance matrix initial value P0, system noise variance matrix Q,
Measuring noise square difference battle array R initial set value is as follows:
X0=[0]1×27;
R=diag ([10-6 10-6 10-6]g)2;
2nd, emulation experiment process
MATLAB simulation analysis are carried out according to IMU systematic parameters error model, detailed process is as follows:
(1) setting initial parameter and the reference value of inertial device error, define initial position, speed and attitude, give just
The parameters such as beginning covariance matrix, system noise variance matrix and observation noise variance matrix;
(2) wave algorithm simulation ship according to setting before and do oscillating motion across the sea, simulation total nominal time sets
For 12 minutes, and export real speed and position and then result is preserved;
(3) according to the true of outputCalculate the pose transformation matrix that navigation coordinate is tied to carrier coordinate systemDue to
Any error is not brought in the solution procedure of the matrix into, so the matrix is theoretical value;
(4) by the Initial value computing system parameter error amount set before, it is added in real IMU output valves, profit
The gyro and accelerometer output data information produced in calibration process is simulated with MATLAB programs, is exported using gyroMeter
Calculate analog simulation output
(5) actual emulation output is released with error with Quaternion Method
(6) utilize what is obtainedWith the f of accelerometer simulation outputbCalculate fn, use Fourth order Runge-Kutta analog simulation
Go out velocity error, that is, Kalman filter observed quantity;
(7) update after sytem matrix, observing matrix, sytem matrix and observing matrix are subjected to sliding-model control, brought into
In Kalman equations, it is filtered;
(8) filtered quantity of state is preserved, exports simulation curve.
(9) last, according to systematic parameter simulation curve, estimating system parameter is simultaneously compensated.Before and after simulation data compensation
The simulation estimate Comparative result curve map of velocity error and attitude error, analysis result is drawn a conclusion.
3rd, the simulation experiment result
Above-mentioned simulation result shows:
(1) ship, due to the impact of wave, produces oscillating motion in the process of navigation.The present invention can waved approximately
Under conditions of, at 10 minutes or so with regard to part system error parameter can be calibrated, and without passing through turntable benchmark or artificial turn
Dynamic, the excitation reasonably produced using the oscillating motion of ship can be achieved with the automatic Calibration of IMU systematic parameters.
(2) velocity error and attitude error after compensating are substantially better than the result before compensation.Therefore, demonstrate and carry in theory
The ship self adaptation gone out, which waves scaling method, effectively on-line proving to go out systematic error parameter, reduce the mistake of inertial navigation system
Difference, meets high accuracy FOG-IMU use demand, so as to improve the navigation accuracy of inertial navigation system.
(5), embodiment
Illustrate below and the present invention is described in more detail:
(1) initial alignment of systematic parameter is completed in laboratory, the related debugging of fiber-optic gyroscope strapdown inertial navigation system is completed
Work.
(2) fiber-optic gyroscope strapdown inertial navigation system is arranged on ship center, after preheating, starts to gather the navigation of IMU outputs
Data.
(3) determine initial state information to complete system coarse alignment according to IMU output, then determined according to coarse alignment
Attitude information pass through a series of strapdowns resolve completion system fine alignment.
(4) inertia device input/output model is set up, it is then determined that the state equation and observational equation of Kalman filter.
(5) during ship's navigation, ship does approximate oscillating motion with wave, makes full use of it to produce inertia device
Excitation.
(6) systematic error parameter is estimated and compensated again according to the Kalman filter equation of foundation, completes demarcation,
Update systematic error parameter.
1) measurement model of inertia device is set up
Due to the limitation of mechanical processing technique, mounting condition equal error factor, a systems of accelerometer system and top in real system
G systems of spiral shell system are not orthogonal coordinate system.According to accelerometer and the input/output relation of gyro, accelerometer and top are provided respectively
Linear calibration's model of spiral shell passage.
The input and output Mathematical Modeling of accelerometer passage is expressed as:
Aa=δ Kafb+δBa+wa
Wherein,Represent output of the accelerometer under a systems;Represent
Force vector is compared in input of the accelerometer under carrier coordinate system b systems;Accelerometer biasSystem
Random noiseKaFor:
Wherein, constant multiplier of the accelerometer on i directions δ Ki(i=x, y, z) is represented, the accelerometer i under a systems
The installation coefficient δ M between the measurement axle on the lower accelerometer j directions of measurement axle and b systems on directionijRepresent.
Laboratory Calibration is joined typically from high-accuracy turntable as benchmark, but in Kalman filter demarcation estimating system error
Do not have turntable benchmark in several processes, so new constraint must be made, a kind of conventional method is defined in the orthogonal seats of IMU
Mark system, i.e., under carrier coordinate system, XbAxle and XaDirection of principal axis is consistent, YbAxle is in O-XaYaIn plane, ZbAxle is true according to the right-hand rule
It is fixed.So δ KaIt will be expressed as again:
Similarly, the Mathematical Modeling of gyro passage is represented by:
Tg=δ Sgωb+δDg+wg
In formula,Represent output of three gyros under g systems;Represent
Input angle speed of three gyros under b systems;The zero of three gyros is inclinedThe random gyro of system
DriftSgFor:
In above formula, constant multiplier of the gyro on i directions δ Si(i=x, y, z) is represented, under g systems on gyro i directions
Measurement axle and b systems time gyro j directions on measurement axle between installation coefficient δ EijRepresent.
2) state equation of Kalman filter is set up
Choose zero inclined, constant multiplier of velocity error, angular error, accelerometer and the gyro of inertial navigation system and system is installed
Number is used as the state variable filtered.It is made up of altogether 27 state parameters:
Wherein,
Wherein, δ VE、δVNWith δ VUSystem east orientation, north orientation and sky orientation speed error, δ φ are represented respectivelyE、δφNWith δ φUPoint
Not Biao Shi system east orientation, north orientation and day to attitude error.
Using " east, north, day " geographic coordinate system as navigational coordinate system, according to SINS velocity errors and attitude error equations,
Set up navigation error equation.Then it is described using linear first-order differential equation, draws the state equation of Kalman filter.
X is 27 dimension system state variableses, and F is 27 × 27 state matrixs for maintaining system, and G is the system noise square of 27 × 6 dimensions
Battle array, W maintains system noise vector for 6, and 6 dimension noise vectors can be expressed as with white noise:
The noise transfer matrix of system can be usedTo represent.Wherein,With(i, j=
1,2,3) the strapdown transition matrix of accelerometer and gyro is represented respectively.
The writeable component block matrix form of state-transition matrix, is represented with F:Wherein:
ReThe radius of the earth is represented, L represents the latitude in SINS locations, ωieRepresent earth rotation angular speed, VEAnd VNPoint
East orientation speed and north orientation speed that Biao Shi be in strapdown solution process.fE、fNAnd fURepresent respectively east orientation that accelerometer measures,
North orientation and day are to output specific force.With(i, j=1,2,3) represents the strapdown transition matrix of accelerometer and gyro respectively.ωb
For real gyro angular speed input value.
3) observational equation for the Kalman filter set up:
During parameters revision, it is impossible to the accurate attitude error for obtaining carrier.And inertial navigation system is with Ship Swaying
Line is not present in calibration process to move, angular movement is only existed, now the speed of navigation calculation is zero, and position is constant.Pass through speed
Integration obtains the positional information of carrier, therefore using velocity error as observed quantity.
Z=[δ VE δVN δVU]T
Using IMU velocity error as observed quantity, then the measurement equation in filtering equations is represented by:
Z=HX+v
In above formula, H and v are respectively:
H=[diag { 111 } 03×24], v=[vx vy vz]T
Wherein, H represents observing matrix, and v, which is represented, measures noise.
4) error parameter is compensated
Result is modified using the method based on Kalman filter estimating system error parameter, FOG- can be obtained
IMU systematic parameter High Definition Systems error parameter results.Afterwards, systematic parameter is compensated, is added to actual inertial navigation
In system, it is determined that whether the parameter of demarcation can improve the precision of system.
The method compensated according to systematic error parameter, inertial navigation system velocity error is arrived by the compensation of smart Calibration Simulation estimated result
In attitude error equations, velocity error and attitude error after being compensated, the error comparing result before and after output compensation.