CN102997892B - Land type navigation system height combination method based on inertia/mileage meter/barometric height - Google Patents

Abstract

The invention belongs to the technical field of land type inertial navigation, and particularly relates to a land type navigation system height combination method based on inertia/mileage meter/barometric height. According to the method, a difference value between a barometric height and an inertia/mileage combination height is adopted as an observation value, a least square method is adopted to evaluate parameters in an inertia/mileage meter height combination error model, and the inertia/mileage height is corrected by using the evaluated parameters. In the prior art, the existing land type navigation system height combination method can not concurrently meet requirements of high precision, electromagnetic interference resistance, and no limitation by barometric altimeter height accuracy and pitch angle error. A purpose of the present invention is to solve technical problems in the prior art. The land type navigation system height combination method has the following beneficial effects: three information such as the inertial navigation, the mileage meter and the barometric height are fused, such that height error inhibition at different vehicle/road condition changes can be achieved, and requirements of high precision, electromagnetic interference resistance, and no limitation by barometric altimeter height accuracy and pitch angle error can be concurrently met.

Description

Based on inertia/odometer/barometer altitude land navigational system altitude combination method

Technical field

The invention belongs to land technical field of inertial, be specifically related to a kind of land navigational system altitude combination method based on inertia/odometer/barometer altitude.

Background technology

The altitude channel of existing land navigational system adopts inertia/combinations of satellites, inertia/form such as barometer altitude combination and inertia/odometer combination usually.The vertical accuracy of inertia/combinations of satellites is high, but depends on the satellite navigation system such as foreign GPS, GLOANSS, and is subject to the impact of the many factors such as electromagnetic interference (EMI) and terrain shading; The vertical accuracy of inertia/barometer altitude combination is limited to the vertical accuracy of pressure altimeter; Owing to there is angle of pitch error in inertia/odometer combination, and angle of pitch error can change to some extent with the fluctuating on carload and road surface, and its vertical error is with traveling mileage accumulation.

Summary of the invention

The technical problem to be solved in the present invention be existing land navigational system altitude combination method cannot meet simultaneously high precision, electromagnetism interference, not by the requirement of pressure altimeter vertical accuracy and angle of pitch error limitation.

Technical scheme of the present invention is as described below:

A kind of land navigational system altitude combination method based on inertia/odometer/barometer altitude, the method with the difference of barometer altitude and inertia/mileage combined altitudes for observed quantity, adopt least square method to estimate the parameter in inertia/odometer altitude combination error model, and utilize the parameter estimated to revise inertia/mileage height; Specifically comprise the steps:

Step 1. sets up inertia/odometer combined altitudes error model; Step 2. parameter estimation; Step 3. error compensation.

Preferably, inertia in step 1/odometer combined altitudes error model is: h _k=h _k-1+ △ D _k× sin α _k

△h _k＝k ₁D _k,cosα+k ₂D _k,sin2α

D _k,cosα＝D _k-1,cosα+△D _k×cosα _k

D _k,sin2α＝D _k-1,sin2α+△D _k×sin2α _k

In formula:

H _krepresent k moment inertia/mileage combined altitudes, unit: rice;

△ D _krepresent the mileage increment between the k-1 moment to k moment, unit: rice;

α _krepresent the angle of pitch in k moment, unit: radian;

△ h _krepresent the error of k moment inertia/mileage combined altitudes, unit: rice;

D _{k, cos α}represent the k moment, the cosine mileage accumulation amount of odometer, unit: rice;

D _{k, sin2 α}represent the k moment, the sinusoidal mileage accumulation amount of odometer, unit: rice;

K ₁, k ₂represent error parameter to be estimated.

Parameter estimation is carried out by following formula in step 2:

$P_k=[P_{k-1}-P_{k-1}{H}_k^T{(I+H_k{P}_{k-1}{H}_k^T)}^{-1}{H}_k{P}_{k-1}]$

${\hat{X}}_k={\hat{X}}_{k-1}+P_k{H}_k^T(Z_k-H_k{\hat{X}}_{k-1})$

In formula:

representing parameter to be estimated, is [k ₁k ₂] ^t, ${\hat{X}}_0={\left[\begin{array}{cc}0& 0\end{array}\right]}^T;$

P _krepresent 2 × 2 dimension matrixes, $P_0=\left[\begin{array}{cc}1& 0\\ 0& 1\end{array}\right];$

H _krepresent [D _{k, cos α}d _{k, sin2 α}];

Z _krepresent observed quantity, the i.e. difference of barometer altitude and inertia/mileage combined altitudes;

With Z _kfor independent variable, with k ₁, k ₂for dependent variable, least square method is adopted to determine k ₁, k ₂.

Error compensation is carried out by following formula in step 3:

${\hat{h}}_k=h_k+H_k{\hat{X}}_k$

In formula:

H _krepresent k moment inertia/mileage combined altitudes, unit: rice;

represent revised height, unit: rice.

Beneficial effect of the present invention is:

Land navigational system altitude combination method based on inertia/odometer/barometer altitude of the present invention is by adopting inertial navigation, odometer and barometer altitude three kinds of information fusion, realize vertical error under different car/road condition change to suppress, can meet simultaneously high precision, electromagnetism interference, not by the requirement of pressure altimeter vertical accuracy and angle of pitch error limitation.

Embodiment

Below in conjunction with embodiment, the land navigational system altitude combination method based on inertia/odometer/barometer altitude of the present invention is described in detail.

Land navigational system altitude combination method based on inertia/odometer/barometer altitude of the present invention with the difference of barometer altitude and inertia/mileage combined altitudes for observed quantity, adopt least square method to estimate the parameter in inertia/odometer altitude combination error model, and utilize the parameter estimated to revise inertia/mileage height.Concrete steps are as follows:

Step 1. sets up inertia/odometer combined altitudes error model

h _k＝h _k-1+△D _k×sinα _k(1)

△h _k＝k ₁D _k,cosα+k ₂D _k,sin2α(2)

D _k,cosα＝D _k-1,cosα+△D _k×cosα _k(3)

D _k,sin2α＝D _k-1,sin2α+△D _k×sin2α _k(4)

In formula:

H _krepresent k moment inertia/mileage combined altitudes, unit: rice;

△ D _krepresent the mileage increment between the k-1 moment to k moment, unit: rice;

α _krepresent the angle of pitch in k moment, unit: radian;

△ h _krepresent the error of k moment inertia/mileage combined altitudes, unit: rice;

D _{k, cos α}represent the k moment, the cosine mileage accumulation amount of odometer, unit: rice;

D _{k, sin2 α}represent the k moment, the sinusoidal mileage accumulation amount of odometer, unit: rice;

K ₁, k ₂represent error parameter to be estimated.

Step 2. parameter estimation

$P_k=[P_{k-1}-P_{k-1}{H}_k^T{(I+H_k{P}_{k-1}{H}_k^T)}^{-1}{H}_k{P}_{k-1}]$ (5)

${\hat{X}}_k={\hat{X}}_{k-1}+P_k{H}_k^T(Z_k-H_k{\hat{X}}_{k-1})$

In formula:

representing parameter to be estimated, is [k ₁k ₂] ^t, ${\hat{X}}_0={\left[\begin{array}{cc}0& 0\end{array}\right]}^T;$

P _krepresent 2 × 2 dimension matrixes, $P_0=\left[\begin{array}{cc}1& 0\\ 0& 1\end{array}\right];$

H _krepresent [D _{k, cos α}d _{k, sin2 α}];

Z _krepresent observed quantity, the i.e. difference of barometer altitude and inertia/mileage combined altitudes.

With Z _kfor independent variable, with k ₁, k ₂for dependent variable, least square method is adopted to determine k ₁, k ₂

Step 3. error compensation

${\hat{h}}_k=h_k+H_k{\hat{X}}_k---\left(6\right)$

In formula:

H _krepresent k moment inertia/mileage combined altitudes, unit: rice;

represent revised height, unit: rice.

Embodiment 1

First parameter initialization is carried out: ${\hat{X}}_0={\left[\begin{array}{cc}0& 0\end{array}\right]}^T,$ $P_0=\left[\begin{array}{cc}1& 0\\ 0& 1\end{array}\right].$

And then carry out parameter estimation:

If during 1s, D _{0, cos α}=0, D _{0, sin2 α}=0, obtain △ D by odometer measurement ₁=1.194, obtain α by inertial navigation measurement ₁=-28.248 °, the D calculated by inertia/odometer combined altitudes error model Chinese style (3) _{1, cos α}for 1.1518m, the D calculated by formula (4) _{1, sin2 α}for-0.8999m, the difference Z of barometer altitude and inertia/mileage combined altitudes ₁for 0.0978m, the method obtaining barometer altitude and inertia/odometer combined altitudes is known to the skilled person general knowledge, then H ₁=[1.1518-0.8999], Z ₁=[0.9078].

During 1s, can be calculated according to formula (5):

$P_1=[P_0-P_0{H}_1^T{(I+H_1{P}_0{H}_1^T)}^{-1}{H}_1{P}_0]=\left[\begin{array}{cc}0.577& 0.3305\\ 0.3305& 0.7418\end{array}\right]$

${\hat{X}}_1={\hat{X}}_0+P_1{H}_1^T(Z_1-H_1{\hat{X}}_0)=\left[\begin{array}{c}0.3334\\ -0.2604\end{array}\right]$

I.e. k during 1s ₁=0.3334, k ₂=-0.2604.

Adopt least square method to carry out parameter recursion when estimating, estimates of parameters increases with observation data and is tending towards stable state, and estimated accuracy improves thereupon.

If during 499s, according to each parameter that last beat of data calculates be

X ₄₉₉＝[0.0004 -0.7315] ^T， $P_{499}=\left[\begin{array}{cc}0& 0\\ 0& 0.001\end{array}\right],$ H ₄₉₉＝[3000.036 7.706]。

During 500s, obtain △ D by odometer measurement ₅₀₀=2.3, obtain α by inertial navigation measurement ₅₀₀=10.1 ° is H by formula (3) and formula (4) calculated value ₅₀₀=[3002.3 8.5]; According to barometer altitude and the inertia/mileage combined altitudes in 500s moment, the difference that can obtain the two is Z ₅₀₀=[-3.5922].

Then during 500s, as follows according to formula (5) each estimates of parameters:

$P_{500}=[P_{499}-P_{499}{H}_{500}^T{(I+H_{500}{P}_{499}{H}_{500}^T)}^{-1}{H}_{500}{P}_{499}]=\left[\begin{array}{cc}0& 0\\ 0& 0.001\end{array}\right]$ ，

${\hat{X}}_{500}={\hat{X}}_{499}+P_{500}{H}_{500}^T(Z_{500}-H_{500}{\hat{X}}_{499})=\left[\begin{array}{c}0.0004\\ -0.728\end{array}\right]$

I.e. k during 500s ₁=0.0004, k ₂=-0.728.

Finally carry out error compensation:

If during 500s, inertia/mileage combined altitudes is h ₅₀₀=32.6941, then the height after utilizing the parametric compensation estimated according to formula (6) is ${\hat{h}}_{500}=h_{500}+H_{500}{\hat{X}}_{500}=37.6221.$

In the present embodiment, the height measurements being generally considered the higher GPS of precision is utilized to be 38m, the measured value of pressure altimeter is 40.1m, inertia/odometer combined altitudes is 42.1m, it can thus be appreciated that, the combined altitudes that patent of the present invention calculates closer to the measured value of GPS height, will improve measuring accuracy relative to pressure altimeter and inertia/odometer combined method; And its comparatively gps system more can resist electromagnetic interference (EMI); The combination of barometer altitude and inertia/odometer combined altitudes enables this method not be subject to the requirement of pressure altimeter vertical accuracy and angle of pitch error limitation.

Claims (1)

1. one kind based on inertia/odometer/barometer altitude land navigational system altitude combination method, it is characterized in that: the method with the difference of barometer altitude and inertia/mileage combined altitudes for observed quantity, adopt least square method to estimate the parameter in inertia/odometer altitude combination error model, and utilize the parameter estimated to revise inertia/mileage height; Specifically comprise the steps:

Step 1. sets up inertia/odometer combined altitudes error model;

Step 2. parameter estimation;

Step 3. error compensation;

Inertia in step 1/odometer combined altitudes error model is:

h _k＝h _k-1+ΔD _k×sinα _k

Δh _k＝k ₁D _k,cosα+k ₂D _k,sin2α

D _k,cosα＝D _k-1,cosα+ΔD _k×cosα _k

D _k,sin2α＝D _k-1,sin2α+ΔD _k×sin2α _k

In formula:

H _krepresent k moment inertia/mileage combined altitudes, unit: rice;

Δ D _krepresent the mileage increment between the k-1 moment to k moment, unit: rice;

α _krepresent the angle of pitch in k moment, unit: radian;

Δ h _krepresent the error of k moment inertia/mileage combined altitudes, unit: rice;

D _{k, cos α}represent the k moment, the cosine mileage accumulation amount of odometer, unit: rice;

D _{k, sin2 α}represent the k moment, the sinusoidal mileage accumulation amount of odometer, unit: rice;

K ₁, k ₂represent error parameter to be estimated;

Parameter estimation is carried out by following formula in step 2:

$P_k=\left[P_{k-1}{P}_{k-1}{H}_k^T{(I+H_k{P}_{k-1}{H}_k^T)}^{-1}{H}_k{P}_{k-1}\right]$

${\hat{X}}_k={\hat{X}}_{k-1}+P_k{H}_k^T(Z_k-H_k{\hat{X}}_{k-1})$

In formula:

representing parameter to be estimated, is [k ₁k ₂] ^t, ${\hat{X}}_0{\left[\begin{array}{cc}0& 0\end{array}\right]}^T;$

P _krepresent 2 × 2 dimension matrixes, $P_0=\left[\begin{array}{cc}1& 0\\ 0& 1\end{array}\right];$

H _krepresent [D _{k, cos α}d _{k, sin2 α}];

Z _krepresent observed quantity, the i.e. difference of barometer altitude and inertia/mileage combined altitudes;

With Z _kfor independent variable, with k ₁, k ₂for dependent variable, least square method is adopted to determine k ₁, k ₂;

Error compensation is carried out by following formula in step 3:

${\hat{h}}_k=h_k+H_k{\hat{X}}_k$

In formula:

H _krepresent k moment inertia/mileage combined altitudes, unit: rice;

represent revised height, unit: rice.