CN103292809A - Single-shaft rotary type inertial navigation system and special error self-compensation method thereof - Google Patents

Abstract

The invention relates to a single-shaft rotary type inertial navigation system. The invention further relates to a special error self-compensation method of the single-shaft rotary type inertial navigation system. The single-shaft rotary type inertial navigation system comprises an indexing mechanism and a single-shaft rotary type inertial navigation system inertial measurement unit, wherein the single-shaft rotary type inertial navigation system inertial measurement unit is mounted on an inertial measurement unit mounting plane; the inertial measurement unit mounting plane and the indexing mechanism are connected together; coordinate axes of the single-shaft rotary type inertial navigation system inertial measurement unit are vertical to each other two by two; each coordinate axis is provided with a gyroscope and an accelerometer. According to the single-shaft rotary type inertial navigation system disclosed by the invention, real-time drifting estimation is implemented by adopting a manner of realizing an adjustable inclined angle of an IMU (Inertial Measurement Unit) mounting plane; the inclined angle can be dynamically readjusted at intervals, so as to further improve the compensation effect of the system; a previous process of recalibrating in a laboratory with a high-precision inertial navigation testing rotary table can be finished in field in a use process, and the guarantee and maintenance costs of an operation period of the inertial navigation system are greatly reduced.

Description

The rotary inertial navigation system of a kind of single shaft and special-purpose error method of self compensation thereof

Technical field

The present invention relates to the rotary inertial navigation system of a kind of single shaft, the invention still further relates to the error compensating method of the rotary inertial navigation system special use of a kind of single shaft.

Background technology

Inertial navigation system is the navigational system of present most widely used a kind of complete autonomous type, just can realize needed all navigation informations because it relies on the information of self fully, and high crypticity and reliability have determined its critical role militarily.Inertial navigation system mainly is made up of inertia device gyroscope and accelerometer, and the precision of inertia device has determined the precision of whole inertial navigation system.And the error of inertia device generally is divided into constant value drift sum of errors Random Drift Error two parts, generally, the error of inertia device all can be along with the time gradually changes, when starting inertial navigation system at every turn, they all have certain differently with the last time, and the navigational system precision when this moves inertial navigation system has very big influence.The inertial navigation system that works long hours for needs particularly, the error of inertia device can cause that positioning error that inertial navigation system is accumulated in time and attitude to a certain degree disperse error, and therefore, they are the principal elements that influence the inertial navigation system performance.

Yet the constant value drift sum of errors of inertia device becomes Random Drift Error slowly can effectively be compensated, and the rotation modulation technique is exactly a kind of technology that inertia device constant value drift sum of errors becomes drift error slowly that compensates effectively.This technology is passed through Inertial Measurement Unit (Inertial measurement unit, IMU) rotation in a certain way reach the compensation inertia device the constant value drift sum of errors become the drift error purpose slowly, reduce it to the influence of inertial navigation system precision by the effective compensation to the inertia device error.At present, the U.S. utilizes this technology successfully to develop high precision single shaft and the rotary inertial navigation systems of twin shaft such as MK39MOD3C, MK49 and AN/WSN-7, is equipped in batches in many naval vessels and battleship of the U.S. and naval of NATO, and has obtained good effect.

Single shaft rotation modulation can effectively compensate with the rotating shaft vertical direction on the constant value drift sum of errors of inertia device become Random Drift Error slowly, but can not compensate with the turning axle parallel direction on the constant value drift sum of errors become Random Drift Error slowly.If want to eliminate the drift error on all directions, on the angle that changes system architecture, can adopt the mode of twin shaft rotation modulation or three rotation modulation to realize, but can sharply increase complicacy and the cost of system architecture like this, moreover will realize that like this effect of high-precision transposition scheme control also has a lot of difficult problems to need to solve in the engineering application.Therefore, the inertia device constant value drift sum of errors that again can full remuneration falls on all for the modulation system that neither changes system on the basis of existing single shaft rotation modulation system becomes drift error slowly, from the setting angle allocation plan angle of the rotary inertial navigation system IMU of existing single shaft on indexing mechanism, the drift error of eliminating all directions by the indexing mechanism control scheme of using angle with rational allocation plan and combination to realize is the direction that should consider emphatically at present.

In core periodical and patent inquiry, all do not find to invent therewith similar method introduction at present.

Summary of the invention

The object of the present invention is to provide a kind of rotary inertial navigation system of single shaft that reduces system cost, the present invention also aims to provide a kind of special-purpose error method of self compensation of the rotary inertial navigation system of single shaft of simplifying the clearing step.

The object of the present invention is achieved like this:

The rotary inertial navigation system of single shaft, comprise indexing mechanism, the rotary inertial navigation system Inertial Measurement Unit of single shaft, the rotary inertial navigation system Inertial Measurement Unit of single shaft is installed on the Inertial Measurement Unit mounting plane, Inertial Measurement Unit mounting plane and indexing mechanism link together, the coordinate axis x of the rotary inertial navigation system Inertial Measurement Unit of single shaft _sAxle, y _sAxle, z _sAxle is vertical mutually in twos, wherein z _sAxle is perpendicular to the Inertial Measurement Unit installed surface, and the Inertial Measurement Unit mounting plane can be along x _sAxle or y _sAxle tilts, and gyroscope and accelerometer all are installed on every coordinate axis.

The special-purpose error method of self compensation of the rotary inertial navigation system of single shaft comprises the steps:

(1) system initialization, the initial alignment of under static condition, navigating;

(2) start indexing mechanism, reach constant operation angular velocity from zero rotating speed;

(3) the indexing mechanism tilt adjustment is carried out the error modulation;

(4) gather on three orthogonal directionss of carrier of gyroscope and accelerometer output angular velocity and acceleration output signal with respect to inertial coordinates system, the signal of gathering is carried out filtering, image data is carried out being tied to from inertial coordinate the conversion of navigation coordinate system, adopt conventional navigation calculation algorithm to carry out navigation calculation, obtain carrier real-time navigation information;

(5) output information of navigation information and GPS is made difference and calculated, obtain the size of placement error value;

(6) according to the positioning error that calculates, whether the error of inertial navigation system reaches the minimum value of system requirements, if reached system requirements, then execution in step (4) and step (5) are up to making placement error value reach minimum; If do not reach system requirements, then execution in step (3) is regulated indexing mechanism, changes Inertial Measurement Unit mounting plane inclination angle, and execution in step (4) and step (5) are up to making placement error value reach minimum.

Navigation information comprises attitude information and locating information.

Beneficial effect of the present invention is:

The present invention comes the realization system to estimate in real time and floats by the IMU installed surface being realized the adjustable mode in pitch angle, just can dynamically reset to the pitch angle at set intervals, the compensation effect of further raising system, can on-the-spot finish the process of in the past demarcating again in the laboratory with High Accuracy Inertial test table in the use of the present invention, greatly reduce the guarantee maintenance cost of inertial navigation system runtime.

Description of drawings

Fig. 1 is the rotary inertial navigation system scheme of installation of single shaft;

Fig. 2 tilts to install the coordinate transform synoptic diagram around pitch axis;

Fig. 3 tilts to install the coordinate transform synoptic diagram around axis of roll;

Fig. 4 is the rotary inertial navigation of single shaft and special-purpose error method of self compensation system control block diagram thereof;

Fig. 5 is the rotary inertial navigation system of single shaft and special-purpose error method of self compensation program flow chart thereof.

Embodiment

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

Sequence number explanation among the figure:

1 ... IMU, 2 ... three accelerometers, 3 ... three gyroscopes, 4 ... indexing mechanism, 5 ... turning axle, 6 ... IMU installed surface, 7 ... IMU output signal, 8 ... IMU installed surface incidence regulating mechanism inclination angle output signal, 9 ... CPU control dip angle signal and incidence regulating mechanism inclination angle monitor signal, 10 ... indexing mechanism angular signal, 11 ... indexing mechanism angular signal and CPU control angular signal.

The present invention be directed to present single shaft rotation inertial navigation system can not compensate the inertia device constant value drift sum of errors that makes progress with turning axle parallel shafts top and become Random Drift Error slowly, and adopt twin shaft or three rotation schemes can make the one-piece construction of system become complicated, increase the problem that can become loaded down with trivial details of resolving of system cost and system, proposed the rotary inertial navigation system of a kind of single shaft and special-purpose error method of self compensation thereof.

The present invention is installed on the rotary inertial navigation system IMU of single shaft on the IMU installed surface of tilt adjustable, rational setting angle is set, can become Random Drift Error slowly by the constant value drift sum of errors that rotates to modulate on three axles of inertia device, thereby improve the long-time navigation accuracy of inertial navigation system.

The rotary inertial navigation system of single shaft comprises indexing mechanism, the rotary inertial navigation system IMU of single shaft.The rotary inertial navigation system IMU of single shaft is installed on the indexing mechanism, the coordinate axis x of the rotary inertial navigation system IMU of single shaft _sAxle, y _sAxle, z _sAxle is vertical mutually in twos, wherein z _sAxle is perpendicular to the IMU installed surface of indexing mechanism, and the IMU installed surface can be along x _sAxle or y _sAxle tilts, and gyroscope and accelerometer all are installed on every coordinate axis.

The special-purpose error method of self compensation of the rotary inertial navigation system of single shaft comprises the steps:

(1) system initialization, the initial alignment of under static condition, navigating;

(2) start indexing mechanism, reach constant operation angular velocity from zero rotating speed;

(3) the rotary inertial navigation system indexing mechanism of single shaft tilt adjustment is carried out the error modulation;

(4) gather on three orthogonal directionss of carrier of inertia device gyroscope and accelerometer output angular velocity and acceleration output signal with respect to inertial coordinates system, and finish the filtering of gathering signal is handled, realize that image data is tied to the conversion process of navigation coordinate system from inertial coordinate, adopt conventional navigation calculation algorithm to realize navigation calculation at last, obtain navigation informations such as the real-time attitude information of carrier and locating information;

(5) navigation information that will be drawn by navigation calculation and GPS etc. more the output information of high precision type navigational system do the difference computing, and draw the size of error amount, particularly the size of positioning error;

(6) according to the positioning error real-time judge that calculates under the long-play condition, whether the error of inertial navigation system reaches given minimum value (as 24 hours positioning errors less than 1 nautical mile), if reached system requirements, then proceed the navigation calculation process of step (4) and the error comparison procedure of step (5), provide the optimal performance of system by real-time error judgment.If do not reach system requirements, then repeat step (3), regulate inclination angle mechanism and change the inclination angle size, and repeat the navigation calculation of step (4) and the error comparison procedure of step (5), by regulating in real time and relatively making system performance reach optimum.

The present invention also has some characteristics like this:

This patent is applicable to the improvement that improves the rotary inertial navigation system output accuracy of single shaft method;

By the method that the pitch angle of IMU installed surface is adjustable, realize complicated twin shaft rotation modulation and three purposes that rotation is modulated with certain angle configurations, can make inertial navigation system peculiar to vessel when long boat, realize the precise navigation requirement under the oceangoing voyage journey condition;

According to system's mounting means of reality, the compensation policy that two kinds of mount schemes are eliminated the azimuth axis drift error has been proposed, can carry out Scheme Choice according to the actual needs;

Come the realization system to estimate in real time by the adjustable mode in pitch angle and float, just can dynamically reset to the pitch angle at set intervals, further improve the compensation effect of system;

The method not only can provide new inertia device error compensation scheme, and the mounting means of employed tilt adjustable can also provide new method for the on-site proving of IMU, can solve needs to disassemble again after present inertial navigation system uses a period of time, be transported to the trouble that laboratory with High Accuracy Inertial test table is demarcated again, just can finish related work at the scene after using this scheme, greatly reduce the guarantee maintenance cost of inertial navigation system runtime.

The present invention is by the influence of the inertia device error on the rotary inertial navigation system turning axle of single shaft direction to the inertial navigation precision, studied IMU is tilted two kinds of mount schemes are installed around axis of roll around pitch axis inclination installation and IMU, and provided complete angle configurations scheme respectively.

Compare with the rotary inertial navigation system of the single shaft of routine, the method that this patent proposes has been for the raising method of the rotary inertial navigation system precision of single shaft provides a kind of very novel thinking, proposed a kind of simple for structure, the scheme that cost is cheaper.

For example patent of the present invention is done description in more detail below in conjunction with accompanying drawing, need to prove that the employed gyroscope of this system, accelerometer, testing circuit and system, control circuit are typical device and are connected with circuit, and the navigation calculation algorithm of employed navigation calculation algorithm and routine does not have the difference of essence, so no longer its schematic diagram is described:

In conjunction with Fig. 1, Figure 1 shows that rotary inertial navigation system scheme of installation.Wherein indexing mechanism 4 upper parts are inertia device 2 and 3 scheme of installation in 1.Ox among the figure _sy _sz _sBe the IMU coordinate system of three quadratures, and on each axle a gyroscope 3 and accelerometer 2 be installed respectively.Gyroscope on each is used for measuring the angular velocity that rotates around respective shaft, accelerometer is used for measuring the acceleration along respective shaft, just can calculate the speed of carrier then by certain navigation calculation algorithm, attitude information (pitching, rolling and course) and locating information (longitude and latitude).And there is constant value drift sum of errors Random Drift Error in the inertia device on each, this is the main error source of the whole inertial navigation system of influence, particularly can the very big influence of generation to attitude output and the position output of the inertial navigation system of the long-time long-distance running of needs.Can become the effect that Random Drift Error plays periodic modulation slowly to the gyroscope installed among the figure and the constant value drift sum of errors of accelerometer in the mode of rotating IMU, improve the precision of inertial navigation system to a great extent.

Carry out under navigation coordinate system because inertial navigation system resolves process, so t constantly the modulation format fastened at navigation coordinate of inertia device deviation can be expressed as

$\left[\begin{array}{c}{\mathrm{\ϵ}}_E\\ {\mathrm{\ϵ}}_N\\ {\mathrm{\ϵ}}_U\end{array}\right]=C_s^n\left[\begin{array}{c}{\mathrm{\ϵ}}_x^s\\ {\mathrm{\ϵ}}_y^s\\ {\mathrm{\ϵ}}_z^s\end{array}\right]=\left[\begin{array}{c}{\mathrm{\ϵ}}_x^s\cos \mathrm{\ωt}-{\mathrm{\ϵ}}_y^s\sin \mathrm{\ωt}\\ {\mathrm{\ϵ}}_x^s\sin \mathrm{\ωt}+{\mathrm{\ϵ}}_y^s\cos \mathrm{\ωt}\\ {\mathrm{\ϵ}}_z^s\end{array}\right]---\left(1\right)$

Wherein

Be that three gyroscope constant value drift sum of errors on the axle become Random Drift Error slowly, from (1) formula as can be seen the equivalent error on x axle and two horizontal directions of y axle change by sinusoidal (cosine) rule.Average is zero in a swing circle, makes systematic error no longer disperse on long terms.And the inertia device error does not have modulatedly on the turning axle direction, and the inertial navigation system navigation error that it causes is still propagated by original rule.

Be example with the gyroscopic drift error only, from the angle of systematic error this problem be described, after the rotation modulation, the systematic steady state error that gyroscopic drift causes is as follows:

Wherein R, ω _IeBe local latitude, earth radius and rotational-angular velocity of the earth all are normal value.ω is the indexing mechanism rotational angular velocity, can set according to actual conditions.δ V _{X ∞}, δ λ _∞, γ _∞Be respectively east orientation velocity error, latitude error, trueness error and the steady-state error of system.From formula (2) horizontal gyroscopic drift as can be seen

The systematic steady state error γ that causes _∞Present oscillating characteristic, the systematic error DC component is suppressed effectively.And the drift on the turning axle direction Except producing east orientation speed dc error component

Dc error component with latitude Also produce the longitude error item of accumulation in time outward, These errors all are the fundamental components that influences system accuracy.

In conjunction with Fig. 2, mounting plane and pitch axis angle of inclination are α, IMU coordinate system ox _sy _sz _sWith carrier coordinate system ox _by _bz _bHas identical true origin o.Its coordinate transformation relation can be described as: initial time IMU coordinate system ox _sy _sz _s, carrier coordinate system ox _by _bz _bWith navigation coordinate be ox _ny _nz _nOverlap turning axle ο z and ο z _bOverlap, earlier around ο x _bThe angle [alpha] that turns clockwise is namely around ο x _bThe axle anglec of rotation-α, ο x at this moment _s, ο y _sBe positioned at the IMU installed surface, ο z _sParallel with the installed surface normal direction; Then around ο z _sAnglec of rotation β obtains final IMU coordinate system ox _sy _sz _sMeanwhile around the rotation of ο z axle, then the transformational relation of IMU coordinate system and carrier coordinate system is IMU with angular velocity omega:

$C_s^b=C_s^n=\left[\begin{array}{ccc}\cos \mathrm{\&omega;t}& -\sin \mathrm{\&omega;<figure-callout\; id="0"\; label="t"\; filenames="HDA00003186489200012.png"\; state="\{\{state\}\}">t</figure-callout>}& 0\\ \sin \mathrm{\&omega;t}& \cos \mathrm{\&omega;<figure-callout\; id="0"\; label="t"\; filenames="HDA00003186489200012.png"\; state="\{\{state\}\}">t</figure-callout>}& 0\\ 0& 0& 1\end{array}\right]\left[\begin{array}{ccc}1& 0& 0\\ 0& \cos \mathrm{\&alpha;}& -\sin \\ 0& \sin \mathrm{\&alpha;}& \cos \mathrm{\&alpha;}\end{array}\right]\left[\begin{array}{ccc}\cos \mathrm{\&beta;}& -\sin & 0\\ \sin \mathrm{\&beta;}& \cos \mathrm{\&beta;}& 0\\ 0& 0& 1\end{array}\right]$

$=\left[\begin{array}{ccc}\cos \mathrm{\&omega;}t\cos \mathrm{\&beta;}-\sin \mathrm{\&omega;}t\cos \mathrm{\&alpha;}\sin \mathrm{\&beta;}& -\cos \mathrm{\&omega;}t\sin \mathrm{\&beta;}-\sin \mathrm{\&omega;}t\cos \mathrm{\&alpha;}\cos \mathrm{\&beta;}& -\sin \mathrm{\&omega;}t\sin \mathrm{\&alpha;}\\ \sin \mathrm{\&omega;}t\cos \mathrm{\&beta;}+\cos \mathrm{\&omega;}t\cos \mathrm{\&alpha;}\sin \mathrm{\&beta;}& -\sin \mathrm{\&omega;}t\sin \mathrm{\&beta;}+\cos \mathrm{\&omega;}t\cos \mathrm{\&alpha;}\cos \mathrm{\&beta;}& \cos \mathrm{\&omega;}t\sin \mathrm{\&alpha;}\\ -\sin \mathrm{\&alpha;}\sin \mathrm{\&beta;}& -\sin \mathrm{\&alpha;}\cos \mathrm{\&beta;}& \cos \mathrm{\&alpha;}\end{array}\right]$ （3）

So, gyroscope constant value drift

Modulation format on carrier coordinate system can be expressed as:

$\left\{\begin{array}{c}{\mathrm{\&epsiv;}}_x^b=(\cos \mathrm{\&omega;}t\cos \mathrm{\&beta;}-\sin \mathrm{\&omega;}t\cos \mathrm{\&alpha;}\sin \mathrm{\&beta;}){\mathrm{\&epsiv;}}_x^s+(-\cos \mathrm{\&omega;}t\sin \mathrm{\&beta;}-\sin \mathrm{\&omega;}t\cos \mathrm{\&alpha;}\cos \mathrm{\&beta;}){\mathrm{\&epsiv;}}_y^s+(-\sin \mathrm{\&omega;}t\sin \mathrm{\&alpha;}){\mathrm{\&epsiv;}}_z^s\\ {\mathrm{\&epsiv;}}_y^b=(\sin \mathrm{\&omega;}t\cos \mathrm{\&beta;}+\cos \mathrm{\&omega;}t\cos \mathrm{\&alpha;\&beta;}){\mathrm{\&epsiv;}}_x^s+(-\sin \mathrm{\&omega;}t\sin \mathrm{\&beta;}+\cos \mathrm{\&omega;}t\cos \mathrm{\&alpha;}\cos \mathrm{\&beta;}){\mathrm{\&epsiv;}}_y^s+\left(\cos \mathrm{\&omega;}t\sin \mathrm{\&alpha;}\right){\mathrm{\&epsiv;}}_z^s\\ {\mathrm{\&epsiv;}}_z^b=(-\sin \mathrm{\&alpha;}\sin \mathrm{\&beta;}){\mathrm{\&epsiv;}}_x^s+(-\sin \mathrm{\&alpha;}\cos \mathrm{\&beta;}){\mathrm{\&epsiv;}}_y^s+\left(\cos \mathrm{\&alpha;}\right){\mathrm{\&epsiv;}}_z^s\end{array}\right.---\left(4\right)$

Gyroscope constant value drift Projection on carrier coordinate system pitch axis, axis of roll is cyclical variation trend, can not cause dispersing of systematic error on long terms.Drift

At carrier coordinate system ο z _bOn projection be DC component, do not contain the component that the cycle changes, as long as choose reasonable angle [alpha], β, it is zero just making this DC component.Table 1 has provided several relatively angle with rational allocation plans under this mode.α, β have determined the installation site of IMU jointly, and β has determined ο x _sSpatial direction.

Table 1 is around pitch axis anglec of rotation allocation plan

In conjunction with Fig. 3, mounting plane is α around the axis of roll angle of inclination, IMU coordinate system ox _sy _sz _sWith carrier coordinate system ox _by _bz _bHas identical true origin o.This coordinate transformation relation can be described as: initial time IMU coordinate system ox _sy _sz _s, carrier coordinate system ox _by _bz _bWith navigation coordinate be ox _ny _nz _nOverlap turning axle ο z and ο z _bOverlap, earlier around ο y _bAnglec of rotation α, ο x at this moment _s, ο y _sBe positioned at the IMU installed surface, ο z _sOverlap with the installed surface normal direction; Around ο z _sAnglec of rotation β obtains final IMU coordinate system ox _sy _sz _sAround the rotation of ο z axle, then the transformational relation of IMU coordinate system and carrier coordinate system is IMU with angular velocity omega:

$C_s^b=C_s^n=\left[\begin{array}{ccc}\cos \mathrm{\&omega;t}& \mathrm{in\&omega;t}& 0\\ -\sin \mathrm{\&omega;t}& \cos \mathrm{\&omega;<figure-callout\; id="0"\; label="t"\; filenames="HDA00003186489200012.png"\; state="\{\{state\}\}">t</figure-callout>}& 0\\ 0& 0& 1\end{array}\right]\left[\begin{array}{ccc}\cos \mathrm{\&alpha;}& 0& -\sin \mathrm{\&alpha;}\\ 0& 1& 0\\ \sin \mathrm{\&alpha;}& 0& \cos \mathrm{\&alpha;}\end{array}\right]\left[\begin{array}{ccc}\cos \mathrm{\&beta;}& \sin \mathrm{\&beta;}& 0\\ -\sin \mathrm{\&beta;}& \cos \mathrm{\&beta;}& 0\\ 0& 0& 1\end{array}\right]$

$=\left[\begin{array}{ccc}\cos \mathrm{\&omega;}t\cos \mathrm{\&alpha;}\cos \mathrm{\&beta;}-\sin \mathrm{\&omega;}t\sin \mathrm{\&beta;}& -\cos \mathrm{\&omega;}t\cos \mathrm{\&alpha;}\sin \mathrm{\&beta;}-\sin \mathrm{\&omega;}t\cos \mathrm{\&beta;}& \cos \mathrm{\&omega;}t\sin \mathrm{\&alpha;}\\ \sin \mathrm{\&omega;}t\cos \mathrm{\&alpha;}\cos \mathrm{\&beta;}+\cos \mathrm{\&omega;}t\sin \mathrm{\&beta;}& -\sin \mathrm{\&omega;}t\cos \mathrm{\&alpha;}\sin \mathrm{\&beta;}+\cos \mathrm{\&omega;}t\cos \mathrm{\&beta;}& \sin \mathrm{\&omega;}t\sin \mathrm{\&alpha;}\\ -\sin \mathrm{\&alpha;}\cos \mathrm{\&beta;}& \sin \mathrm{\&alpha;}\sin \mathrm{\&beta;}& \cos \mathrm{\&alpha;}\end{array}\right]$ （5）

So, gyroscope constant value drift Modulation format on carrier coordinate system can be expressed as:

$\left\{\begin{array}{c}{\mathrm{\&epsiv;}}_x^b=(\cos \mathrm{\&omega;}t\cos \mathrm{\&alpha;}\cos \mathrm{\&beta;}-\sin \mathrm{\&omega;}t\sin \mathrm{\&beta;}){\mathrm{\&epsiv;}}_x^s+(-\cos \mathrm{\&omega;}t\cos \mathrm{\&alpha;}\sin \mathrm{\&beta;}-\sin \mathrm{\&omega;}t\cos \mathrm{\&beta;}){\mathrm{\&epsiv;}}_y^s+(\cos \mathrm{\&omega;}t\sin \mathrm{\&alpha;}){\mathrm{\&epsiv;}}_z^s\\ {\mathrm{\&epsiv;}}_y^b=(\sin \mathrm{\&omega;}t\cos \mathrm{\&alpha;}\cos \mathrm{\&beta;}+\cos \mathrm{\&omega;}t\sin \mathrm{\&beta;}){\mathrm{\&epsiv;}}_x^s+(-\sin \mathrm{\&omega;}t\cos \mathrm{\&alpha;}\sin \mathrm{\&beta;}+\cos \mathrm{\&omega;}t\cos \mathrm{\&beta;}){\mathrm{\&epsiv;}}_y^s+\left(\sin \mathrm{\&omega;}t\sin \mathrm{\&alpha;}\right){\mathrm{\&epsiv;}}_z^s\\ {\mathrm{\&epsiv;}}_z^b=(-\sin \mathrm{\&alpha;}\cos \mathrm{\&beta;}){\mathrm{\&epsiv;}}_x^s+(-\sin \mathrm{\&alpha;}\sin \mathrm{\&beta;}){\mathrm{\&epsiv;}}_y^s+\left(\cos \mathrm{\&alpha;}\right){\mathrm{\&epsiv;}}_z^s\end{array}\right.---\left(6\right)$

By (6) formula as can be seen, gyroscope constant value drift

Projection on carrier coordinate system pitch axis, axis of roll is cyclical variation trend, can not cause dispersing of systematic error on long terms.Drift

At carrier coordinate system ο z _bOn projection be DC component, do not contain the component that the cycle changes, as long as choose reasonable angle [alpha], β, it is zero just making this DC component.Table 2 has provided several relatively angle with rational allocation plans under this mode.α, β have determined the installation site of IMU jointly, and β has determined ο x _sSpatial direction:

Table 2 is around axis of roll anglec of rotation allocation plan

In addition, need to prove, even the traverse gyro drift error has obtained The optimal compensation, can not guarantee that the sky obtains best compensation effect to accelerometer bias.Yet in real system, the gyroscopic drift error is drifted about to the influence of inertial navigation system much larger than accelerometer to the performance impact of inertial navigation system, is rational so pay the utmost attention to compensation gyroscopic drift.

In conjunction with Fig. 4, the control block diagram of this single shaft rotation inertial navigation system and special-purpose error method of self compensation thereof is set forth: this system mainly comprises four major parts: IMU, IMU installed surface incidence regulating mechanism, indexing mechanism and CPU.Concrete control procedure is as follows:

Step 1, after system's power-up initializing, CPU rotates by certain scheme of rotation by signal 11 control indexing mechanisms, enters step 2;

Step 2, the rotation of indexing mechanism drives mounted thereto IMU with signal 10 thereupon and the dip plane is installed rotates with constant angular velocity omega, enters step 3;

Step 3, IMU installs the dip plane and rotates with Constant Angular Velocity ω with the IMU that signal 8 drives mounted thereto of inclination, enters step 4;

Step 4, the output signal 7 of IMU, the dip angle signal 9 of IMU installed surface incidence regulating mechanism output and the angular signal 11 of indexing mechanism pass to CPU simultaneously, enter step 5;

Step 5, CPU calculates the navigation information of carrier and the control information of being correlated with by navigation calculation, enters step 6;

Step 6, the inclination angle value that CPU regulates IMU installed surface incidence regulating mechanisms by control signal 9, repeating step 4 and step 5 then make the control information that is drawn by step 5 reach minimum value and get final product.

In conjunction with Fig. 5, the rotary inertial navigation system of this single shaft and special-purpose error method of self compensation program operational scheme thereof are described in detail: this patent is with angular velocity and acceleration information on three orthogonal directionss of carrier of rotary inertial navigation system IMU output, in conjunction with the angle configurations scheme information that scheme of rotation information and the IMU installed surface incidence regulating mechanism of indexing mechanism provides, carry out navigation calculation.Finally draw navigation informations such as the real-time attitude information of carrier and locating information, and carry out the control information that error calculates inertial navigation system with the high precision navigational system (as GPS) of other types.This system's operational scheme is as follows:

Step 1, system power on and finish navigation initial alignment process under initialization and the static condition, for real-time navigation provides initial baseline, enter step 2;

Step 2 starts indexing mechanism, makes it reach constant operation angular velocity from zero rotating speed, and makes indexing mechanism move according to predetermined transposition scheme, enters step 3;

Step 3, the running of indexing mechanism drive IMU installed surface incidence regulating mechanism and rotate in the same way, enter step 4;

Step 4, IMU installed surface incidence regulating mechanism drive IMU thereupon will carry out the error modulation with arbitrary feasible angle of inclination allocation plan and the scheme of rotation of indexing mechanism, enter step 5;

Step 5, the CPU navigational computer is gathered on three orthogonal directionss of carrier of inertia device gyroscope and accelerometer output angular velocity and the acceleration output signal with respect to inertial coordinates system, and finish the filtering of gathering signal is handled, realize that image data is tied to the conversion process of navigation coordinate system from inertial coordinate, adopt conventional navigation calculation algorithm to realize navigation calculation at last, obtain navigation informations such as the real-time attitude information of carrier and locating information, enter step 6 and step 8;

Step 6 will be done the difference computing with the output information of high precision type navigational system such as GPS by the navigation information that navigation calculation draws,, and draw the size of error amount, enter step 7;

Step 7, according to the positioning error real-time judge that calculates under the long-play condition, whether the error of inertial navigation system reaches given minimum value (as 24 hours positioning errors less than 1 nautical mile), if reached system requirements, then proceed the navigation calculation process of step (4) and the error comparison procedure of step (5), provide the optimal performance of system by real-time error judgment.If do not reach system requirements, then repeat step (3), regulate inclination angle mechanism and change the inclination angle size, and repeat the navigation calculation of step (4) and the error comparison procedure of step (5), by regulating in real time and relatively making system performance reach optimum; Enter step 8;

Step 8, navigation indicator receives real-time attitude information and the locating information of CPU and shows in real time.

Claims (3)

1. rotary inertial navigation system of single shaft, comprise indexing mechanism, the rotary inertial navigation system Inertial Measurement Unit of single shaft, it is characterized in that: the rotary inertial navigation system Inertial Measurement Unit of single shaft is installed on the Inertial Measurement Unit mounting plane, Inertial Measurement Unit mounting plane and indexing mechanism link together, the coordinate axis x of the rotary inertial navigation system Inertial Measurement Unit of single shaft _sAxle, y _sAxle, z _sAxle is vertical mutually in twos, wherein z _sAxle is perpendicular to the Inertial Measurement Unit installed surface, and the Inertial Measurement Unit mounting plane can be along x _sAxle or y _sAxle tilts, and gyroscope and accelerometer all are installed on every coordinate axis.

2. the special-purpose error method of self compensation of the rotary inertial navigation system of single shaft is characterized in that, comprises the steps:

(1) system initialization, the initial alignment of under static condition, navigating;

(2) start indexing mechanism, reach constant operation angular velocity from zero rotating speed;

(3) the indexing mechanism tilt adjustment is carried out the error modulation;

(4) gather on three orthogonal directionss of carrier of gyroscope and accelerometer output angular velocity and acceleration output signal with respect to inertial coordinates system, the signal of gathering is carried out filtering, image data is carried out being tied to from inertial coordinate the conversion of navigation coordinate system, adopt conventional navigation calculation algorithm to carry out navigation calculation, obtain carrier real-time navigation information;

(5) output information of navigation information and GPS is made difference and calculated, obtain the size of placement error value;

(6) according to the positioning error that calculates, whether the error of inertial navigation system reaches the minimum value of system requirements, if reached system requirements, then execution in step (4) and step (5) are up to making placement error value reach minimum; If do not reach system requirements, then execution in step (3) is regulated indexing mechanism, changes Inertial Measurement Unit mounting plane inclination angle, and execution in step (4) and step (5) are up to making placement error value reach minimum.

3. the special-purpose error method of self compensation of the rotary inertial navigation system of a kind of single shaft according to claim 2, it is characterized in that: described navigation information comprises attitude information and locating information.

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