CN103900571A - Carrier attitude measurement method based on inertial coordinate system rotary type strapdown inertial navigation system - Google Patents

Abstract

The invention belongs to the technical field of inertial navigation, and in particular relates to a carrier attitude measurement method based on an inertial coordinate system rotary type strapdown inertial navigation system, which can be used for measuring a navigation parameter value of a carrier in real time. The carrier attitude measurement method comprises the following steps of performing initial alignment 1 hour after the warm-up of the strapdown inertial navigation system; acquiring a gyroscope output angular speed, an accelerometer output specific force and a turntable output angular rate; measuring a direction cosine matrix between an inertial coordinate system and a coordinate system of a control IMU (inertial measurement unit); measuring a projection of the specific force in a geographical coordinate system; measuring a speed and a position of the carrier; measuring a direction cosine matrix between the inertial system and the geographical system; measuring a projection of a position angular rate of the carrier in the inertial system; measuring a projection of an angular speed in the inertial coordinate system; measuring an attitude rate of the carrier; measuring a direction cosine matrix between a carrier coordinate system and a navigation coordinate system; measuring a longitudinal rolling angle, a transverse rolling angle and a course angle. According to the carrier attitude measurement method, device errors can be completely eliminated, and carrier attitude information is supplied to the system.

Description

A kind of carrier posture measuring method based on the rotary-type strapdown inertial navitation system (SINS) of inertial coordinates system

Technical field

The invention belongs to inertial navigation technology field, be specifically related to a kind of carrier posture measuring method based on the rotary-type strapdown inertial navitation system (SINS) of inertial coordinates system that can be used for the navigational parameter value of measuring in real time carrier.

Background technology

In strapdown inertial navigation system, people have promoted the fast development of inertia device for the lasting research of the inertia device such as gyroscope and accelerometer of formation Inertial Measurement Unit.Device precision is higher, further the cost of boost device precision is just larger, and along with national defense industry is to armament systems low cost, high reliability, the requirement of ease for maintenance is more and more higher, and the positioning precision that therefore adopts error self compensation technology to improve inertial navigation system is one of main direction of inertial technology development.

Fiber-optic gyroscope strapdown inertial navigation system is because the dynamic property of device is unstable, and the feature such as be easily affected by the external environment will be paid special attention to gyro scale factor error and the impact of alignment error on system in choosing twin shaft rotation modulation scheme.The conventional twin shaft rotation modulation type strapdown inertial navitation system (SINS) based on geographic coordinate system cannot be eliminated scale factor error and the impact of alignment error on system, therefore fiber-optic gyroscope strapdown inertial navigation system is adopted to the three axle rotation modulation schemes based on inertial coordinates system, control Inertial Measurement Unit (Inertial Measurement Unit, IMU) successively rotate around inertial coordinate axle according to formulating path, impact with abatement device error on system, and then improve strapdown inertial navitation system (SINS) independent navigation precision.

Gyroscope sensitivity based on inertial coordinates system rotation modulation type strapdown inertial navitation system (SINS) to angular velocity be the angular velocity of rotation of the IMU coordinate system relative inertness coordinate system of design of scheme, neither comprise the attitude information that rotational-angular velocity of the earth information does not comprise again carrier, the attitude information that how to demodulate carrier from Information Monitoring is one of key based on the normal operation of inertial coordinates system rotation modulation type strapdown inertial navitation system (SINS).The z of inertial coordinates system _iaxle is parallel with earth's axis, x _iaxle and y _iaxle is in zero latitude circle plane, and x _iaxle in zero circle of longitude plane, y _iaxle and x _iand z _iform right-handed coordinate system; The x-axis, y-axis and z-axis of geographic coordinate system are pointed to respectively east-north-sky direction; Navigation coordinate system overlaps with geographic coordinate system; The x of IMU coordinate system _saxle, y _saxle and z _saxle is respectively along three sensitive axes directions of gyro.

Summary of the invention

The object of the present invention is to provide a kind of output data of utilizing gyroscope and accelerometer and turntable output angle speed jointly to measure the attitude angle of carrier Relative Navigation coordinate system, realize the navigation feature based on inertial coordinates system rotation modulation type strapdown inertial navitation system (SINS).The carrier posture measuring method based on the rotary-type strapdown inertial navitation system (SINS) of inertial coordinates system.

The object of the present invention is achieved like this:

Step 1: initial alignment is carried out in strapdown inertial navitation system (SINS) start preheating after 1 hour;

Step 2: control the control Inertial Measurement Unit IMU of strapdown inertial navitation system (SINS) around the rotation of inertial coordinate axle, gather gyroscope Output speed

accelerometer output specific force f ^swith turntable output angle speed

Step 3: the gyroscope Output speed gathering according to step 2

measure inertial system and control the direction cosine matrix between Inertial Measurement Unit IMU coordinate system

Step 4: the accelerometer output specific force f gathering according to step 2 ^s, step 3 obtain direction cosine matrix

and direction cosine matrix between inertial system and Department of Geography measure the projection f of specific force in geographic coordinate system ⁿ;

Step 5: the f obtaining according to step 4 ⁿspeed and the position of measuring carrier, be designated as V successively _x, V _y, λ _twith

Step 6: the carrier positions λ obtaining according to step 5 _twith

measure the direction cosine matrix between inertial system and Department of Geography:

In formula, ω _ieit is rotational-angular velocity of the earth;

Step 7: the bearer rate V obtaining according to step 5 _xwith V _ywith step 6 obtain

measure the position angle speed of carrier in the projection of inertial system

Step 8: the gyroscope and the turntable output angle speed that gather according to step 2 with

direction cosine matrix with step 3 acquisition measured angular speed is in the projection of inertial coordinates system

with

Step 9: according to earth rate the transition matrix that step 6 obtains the position angle speed that step 7 obtains is in the projection of inertial system the gyroscope obtaining with step 8 and turntable output angle speed are in the projection of inertial coordinates system

with

measure the attitude speed of carrier:

${\mathrm{\ω}}_{\mathrm{nb}}^n=C_i^n({\mathrm{\ω}}_{\mathrm{is}}^i-{\mathrm{\ω}}_{\mathrm{ie}}^i-{\mathrm{\ω}}_{\mathrm{en}}^i-{\mathrm{\ω}}_{\mathrm{bs}}^i);$

Step 10: the attitude speed obtaining according to step 9

measure the direction cosine matrix between carrier coordinate system and navigation coordinate system

Step 11: obtain according to step 10

measure pitch angle θ, roll angle γ and the course angle ψ of carrier:

θ＝sin ^-1C ₂₃

$\mathrm{\γ}={\mathrm{tg}}^{-1}\frac{{-C}_{13}}{C_{33}},$

$\mathrm{\ψ}={\mathrm{tg}}^{-1}\frac{-C_{21}}{C_{22}}$

In formula, C _ij, i, j=1,2,3 is direction cosine matrix

in each element.

Beneficial effect of the present invention is: the present invention has designed a kind of carrier posture measuring method based on inertial coordinates system rotation modulation type strapdown inertial navitation system (SINS), the method does not comprise carrier movement information for gyrostatic output angle speed in system and cannot directly measure the problem of attitude of carrier, utilize turntable output angle rate information and accelerometer information jointly to measure the attitude angle of carrier, realized the function that attitude of carrier information is provided for system in real time under the prerequisite of complete abatement device error.

Brief description of the drawings

Fig. 1 is the process flow diagram of the carrier posture measuring method based on inertial coordinates system rotation modulation type strapdown inertial navitation system (SINS).

Embodiment

Below in conjunction with accompanying drawing, the present invention is described further.

Principle of the present invention is: the present invention utilizes accelerometer output signal to measure the latitude and longitude information of carrier, and utilize this information to obtain in real time the direction cosine matrix between inertial coordinates system and navigation coordinate system, by this matrix, the angular velocity information of gyroscope and turntable output is combined to the attitude angle speed of measuring carrier again, the attitude angle that finally obtains carrier realizes the object of system navigation.

(1) initial alignment is carried out in strapdown inertial navitation system (SINS) start preheating after 1 hour.

(2) IMU that controls strapdown inertial navitation system (SINS), around the rotation of inertial coordinate axle, gathers gyroscope Output speed simultaneously

accelerometer output specific force f ^swith turntable output angle speed

(3) according to the gyroscope Output speed gathering

measure the direction cosine matrix between inertial system and IMU coordinate system

(4) according to the accelerometer output specific force f gathering ^s, direction cosine matrix between inertial system and Department of Geography

and direction cosine matrix

measure the projection of specific force in geographic coordinate system:

$f^n=C_i^n{C}_s^i{f}^s---\left(1\right)$

(5) according to f ⁿspeed and the position of measuring carrier, be designated as V successively _x, V _y, λ _twith

(6) according to the position λ of carrier _twith

measure the direction cosine matrix between inertial system and Department of Geography:

In formula, ω _ieit is rotational-angular velocity of the earth.

(7) basis and the speed V of carrier _xand V _yobtain the position angle speed of carrier in the projection of inertial system:

In formula, R is earth radius.

(8) according to the gyroscope and the turntable output angle speed that gather with

and direction cosine matrix

measured angular speed is in the projection of inertial coordinates system

with

$\begin{array}{c}{\mathrm{\ω}}_{\mathrm{bs}}^i=C_s^i{\mathrm{\ω}}_{\mathrm{bs}}^s\\ {\mathrm{\ω}}_{\mathrm{is}}^i=C_s^i{\mathrm{\ω}}_{\mathrm{is}}^s\end{array}----\left(4\right)$

(9) according to earth rate

transition matrix

position angle speed is in the projection of inertial system

with the projection at inertial coordinates system of gyroscope and turntable output angle speed with

measure the attitude speed of carrier:

${\mathrm{\ω}}_{\mathrm{nb}}^n=C_i^n({\mathrm{\ω}}_{\mathrm{is}}^i-{\mathrm{\ω}}_{\mathrm{ie}}^i-{\mathrm{\ω}}_{\mathrm{en}}^i-{\mathrm{\ω}}_{\mathrm{bs}}^i)---\left(5\right)$

(10) according to attitude speed

measure the direction cosine matrix between carrier coordinate system and navigation coordinate system

(11) basis

measure pitch angle θ, roll angle γ and the course angle ψ of carrier:

θ＝sin ^-1C ₂₃

$\mathrm{\γ}={\mathrm{tg}}^{-1}\frac{{-C}_{13}}{C_{33}}---\left(6\right)$

$\mathrm{\ψ}={\mathrm{tg}}^{-1}\frac{-C_{21}}{C_{22}}$

In formula, C _ij, i, j=1,2,3 is direction cosine matrix

in each element.

Claims (1)

1. the carrier posture measuring method based on the rotary-type strapdown inertial navitation system (SINS) of inertial coordinates system, is characterized in that:

Step 1: initial alignment is carried out in strapdown inertial navitation system (SINS) start preheating after 1 hour;

Step 2: control the control Inertial Measurement Unit IMU of strapdown inertial navitation system (SINS) around the rotation of inertial coordinate axle, gather gyroscope Output speed accelerometer output specific force f ^swith turntable output angle speed

Step 3: the gyroscope Output speed gathering according to step 2

measure inertial system and control the direction cosine matrix between Inertial Measurement Unit IMU coordinate system

Step 4: the accelerometer output specific force f gathering according to step 2 ^s, step 3 obtain direction cosine matrix

and direction cosine matrix between inertial system and Department of Geography measure the projection f of specific force in geographic coordinate system ⁿ;

Step 5: the f obtaining according to step 4 ⁿspeed and the position of measuring carrier, be designated as V successively _x, V _y, λ _twith

Step 6: the carrier positions λ obtaining according to step 5 _twith

measure the direction cosine matrix between inertial system and Department of Geography:

In formula, ω _ieit is rotational-angular velocity of the earth;

Step 7: the bearer rate V obtaining according to step 5 _xwith V _ywith step 6 obtain

measure the position angle speed of carrier in the projection of inertial system

Step 8: the gyroscope and the turntable output angle speed that gather according to step 2 with

direction cosine matrix with step 3 acquisition

measured angular speed is in the projection of inertial coordinates system

with

Step 9: according to earth rate

the transition matrix that step 6 obtains

the position angle speed that step 7 obtains is in the projection of inertial system

the gyroscope obtaining with step 8 and turntable output angle speed are in the projection of inertial coordinates system

with

measure the attitude speed of carrier:

${\mathrm{\ω}}_{\mathrm{nb}}^n=C_i^n({\mathrm{\ω}}_{\mathrm{is}}^i-{\mathrm{\ω}}_{\mathrm{ie}}^i-{\mathrm{\ω}}_{\mathrm{en}}^i-{\mathrm{\ω}}_{\mathrm{bs}}^i);$

Step 10: the attitude speed obtaining according to step 9

measure the direction cosine matrix between carrier coordinate system and navigation coordinate system

Step 11: obtain according to step 10

measure pitch angle θ, roll angle γ and the course angle ψ of carrier:

θ＝sin ^-1C ₂₃

$\mathrm{\γ}={\mathrm{tg}}^{-1}\frac{{-C}_{13}}{C_{33}},$

$\mathrm{\ψ}={\mathrm{tg}}^{-1}\frac{-C_{21}}{C_{22}}$

In formula, C _ij, i, j=1,2,3 is direction cosine matrix

in each element.