CN105115518A - Inertial navigation system and GPS double antenna course deflection calibration method - Google Patents

Abstract

The invention discloses an inertial navigation system and GPS double antenna course deflection calibration method. The method comprises determining a rectilinear motion distance of an aircraft, when the aircraft moves along a straight line, calculating deflection between a vertical axis course of the aircraft and a course of a GPS double antenna base line, when the aircraft moves along the original aircraft course in the step 2 at velocity in the opposite velocity direction, calculating deflection beta between an inertial navigation system and the vertical axis course of the aircraft, and calculating course deflection between the inertial navigation system and the GPS double antennas. The method realizes error angle calibration in the state of inertial navigation system and GPS double antenna installation in the outer field.

Description

A kind of for inertial navigation system and drift angle, GPS double antenna course scaling method

Technical field

The present invention relates to a kind of for inertial navigation system and drift angle, GPS double antenna course scaling method, belong to Navigation, Guidance and Control technical field.

Background technology

Inertial navigation system is to the movable information of aircraft, and as speed, position, attitude etc. are measured, its advantage has good navigation accuracy at short notice, and inferior position is that inertial navigation system navigation error adds up in time; Gps satellite navigation has good positioning precision, and navigation error is not dispersed in time, therefore adopts inertial navigation and satellite navigation to carry out the navigate mode combined more.Two GPS and inertial navigation system is utilized to navigate, speed, position grouping navigation can not only be carried out, GPS double antenna is installed along direction, inertia combination system course, two GPS can be utilized to measure 2 positions, through calculating base direction course, for inertial navigation system provides initial heading.Now, drift angle is there is between two gps antenna course axle and direction, inertial navigation system course, directly GPS course information can be brought initial error as inertia combination system initial heading, directly affect the navigation accuracy of inertial navigation system, therefore must demarcate drift angle between the two.

Present stage aircraft inertia measuring unit and two GPS baseline course between drift angle demarcate and mostly adopt optical instrument to carry out, namely optical instrument is utilized to demarcate inertial navigation system course and double antenna course respectively, and the drift angle obtaining between the two by heading crossing angle.This kind of method precision is high, and be applicable in the open instrument room of Inertial Measurement Unit aircraft, optical instrument can act directly on the situation of inertial navigation system being carried out course orientation measurement.In the actual condition of Flied emission outside, gps antenna is installed on aircraft outside surface, and optical instrument can be utilized to demarcate GPS baseline course; But inertial navigation system is installed on aircraft interior, optical instrument cannot be utilized to demarcate, optical instrument demarcates the demand that cannot meet outfield and demarcate.

Summary of the invention

Technology of the present invention is dealt with problems and is: overcome the deficiencies in the prior art, there is provided a kind of for inertial navigation system and drift angle, GPS double antenna course scaling method, this method achieves in outfield and inertial navigation system and GPS double antenna all complete demarcation to error angle under installment state.

Technical solution of the present invention is:

It is as follows that one comprises step for inertial navigation system and drift angle, GPS double antenna course scaling method:

(1) aircraft rectilinear motion distance L is determined;

$L=\frac{2R}{\mathrm{\Δ}\mathrm{\α}}\·\frac{180}{\mathrm{\π}}$

Wherein, Δ α represents aircraft longitudinal axis direction course error; R represents GPS positioning precision;

(2) aircraft moves along a straight line, the drift angle α between calculating aircraft longitudinal axis course and GPS double antenna baseline course:

(2a) calculating aircraft reference position point is to the track course H of final position point _v:

Wherein, r _erepresent earth radius;

(2b) drift angle between calculating aircraft longitudinal axis course and GPS double antenna baseline course:

α＝H _GPS-H _V

H _gPSrepresent GPS double antenna baseline course;

(3) aircraft is along constant with aircraft course in step (2), motion side's motion that speed is contrary, calculates the drift angle β between inertial navigation system and aircraft longitudinal axis course:

$\mathrm{\β}=\frac{l_1-l_2}{2}\×\frac{1}{L}\×\frac{180}{\mathrm{\π}}$

Wherein, l ₁when expression is moved along the direction in step (2), the aircraft lateral shift that inertial navigation system measures; l ₂when expression is moved along the direction in step (3), the aircraft lateral shift that inertial navigation system measures;

(4) drift angle, the course χ between inertial navigation system and GPS double antenna is calculated:

χ＝α+β。

The present invention's beneficial effect is compared with prior art:

(1) the present invention utilizes aircraft straight reciprocating motion to carry out drift angle demarcation, without the need to operating at aircraft interior, system under aircraft simple motion state is only relied on to export and externally measured, by appropriate algorithm, can realize Accurate Calibration, easy being easy to of the present invention realizes, improve navigation accuracy, there is higher practical value, for ensureing that the precision of attitude in spacecraft navigation procedure provides important guarantee, improve aircraft reliability of operation.

Accompanying drawing explanation

Fig. 1 is drift angle of the present invention schematic diagram;

Fig. 2 is that the present invention linearly runs schematic diagram;

Fig. 3 is α angle of the present invention scaling method schematic diagram;

Fig. 4 is β angle of the present invention scaling method schematic diagram;

Fig. 5 is β angle of the present invention separation principle schematic diagram.

Embodiment

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is further described in detail.

As shown in Figure 1, 2, 3, the present invention's one is used for inertial navigation system and drift angle, GPS double antenna course scaling method, comprises step as follows:

(1) aircraft rectilinear motion distance L is determined;

$L=\frac{2R}{\mathrm{\Δ}\mathrm{\α}}\·\frac{180}{\mathrm{\π}}$

Wherein, Δ α represents aircraft longitudinal axis direction course error; R represents GPS positioning precision;

(2) aircraft moves along a straight line, the drift angle α between calculating aircraft longitudinal axis course and GPS double antenna baseline course:

(2a) calculating aircraft reference position point is to the track course H of final position point _v:

Wherein, r _erepresent earth radius;

(2b) drift angle between calculating aircraft longitudinal axis course and GPS double antenna baseline course:

α＝H _GPS-H _V

H _gPSrepresent GPS double antenna baseline course, this course need not calculate, and is exported by two GPS navigation system;

(3) aircraft is along constant with aircraft course in step (2), motion side's motion that speed is contrary, calculates the drift angle β between inertial navigation system and aircraft longitudinal axis course:

As shown in Figure 4,5, aircraft moves along a straight line, and because inertial navigation system part and aircraft longitudinal axis exist drift angle β, then inertial navigation system part can measure side acceleration, can obtain the lateral shift L1 of inertia part of detecting thus.By known aircraft rectilinear motion distance L, the drift angle β in inertia part of detecting course and aircraft longitudinal axis course can be calculated.As shown in Figure 4.β computing method are

$\mathrm{\β}=\frac{L1}{L}\×\frac{180}{\mathrm{\π}},$ Unit: o

In measuring process, read the side acceleration meter output valve of inertial navigation system, carry out integral and calculating, obtain lateral shift value.Because accelerometer exists the error of zero, the lateral shift therefore obtained by accelerometer measures is the coupling value (l of the lateral shift L1 of drift angle β introducing and the lateral shift l ' of accelerometer trueness error introducing ₁when expression is moved along the direction in step (2), the aircraft lateral shift that inertial navigation system measures), i.e. l ₁=L1+l '.

Positive reverse movement is utilized to be separated two class errors.

Aircraft by initial position by after constant speed movement to final position, aircraft longitudinal direction remains unchanged, and to move back starting point with identical velocity reversal.

In heterodromous process, equal and opposite in direction in the lateral shift L1 caused by inertial navigation system and aircraft drift angle β and positive movement process, direction is contrary; Lateral shift l ' size the direction caused by accelerometer error Δ a is all constant.Therefore final lateral shift result is l ₂=-L1+l ' (l ₂when expression is moved along the direction in step (3), the aircraft lateral shift that inertial navigation system measures).As shown in Figure 5.Then

$\left\{\begin{array}{c}{l}_1=L1+l^{\′}\\ l_2=-L1+l^{\′}\end{array}\right.$

Can obtain according to above two formulas, the lateral shift L1 caused by drift angle β between inertial navigation system and aircraft longitudinal axis is

$L1=\frac{l_1-l_2}{2}$

So:

$\mathrm{\β}=\frac{l_1-l_2}{2}\×\frac{1}{L}\×\frac{180}{\mathrm{\π}}$

(4) drift angle, the course χ between inertial navigation system and GPS double antenna is calculated:

χ＝α+β。

With a specific embodiment, principle of work of the present invention and the course of work are further explained below.

In aircraft linear motion, the positional information that motion initial point and terminating point geographical position coordinates provide by GPS is determined, GPS positioning precision is R (1.8m (CEP)), then the aircraft longitudinal axis rudder caused by GPS positioning error to error delta α is

$\mathrm{\Δ}\mathrm{\α}=\±\frac{2\×R}{L}rad$

Model General Requirements system course precision is 0.1 °, for ensureing this navigation accuracy, then needs the distance moved along a straight line to be

$L=\frac{3.6}{\mathrm{\Δ}\mathrm{\α}}\·\frac{180}{\mathrm{\π}}\≈2062m$

Getting initial point position is terminating point position is move distance is

Meet the requirement that move distance is greater than 2062m.

Then track course is

In this process, GPS double antenna exports course and is, i.e. H _gPS=58.37 °.

Obtain

α＝H _GPS-H _V＝58.37°-55.4147°＝2.8543°

In test process, aircraft point-to-point speed is about 5m/s.

In positive movement process, inertial navigation system lateral position exports as l ₁=266.3225m

In reverse movement process, inertial navigation system lateral position exports as l ₂=77.13222m

Obtain

$L1=\frac{l_1-l_2}{2}=94.59514m$

Then

Drift angle, course then between inertial navigation system and GPS double antenna is

χ＝α+β＝2.8543°+1.83241＝4.6867°

Analyzed by above specific embodiment, can find out that the present invention demarcates the drift angle, course that obtains on the basis ensureing stated accuracy, have stronger operability, overcome the difficult problem cannot measuring its drift angle, course after inertial navigation system completes installation, accuracy is high.

The content be not described in detail in instructions of the present invention belongs to the known technology of those skilled in the art.

Claims (1)

1., for inertial navigation system and drift angle, a GPS double antenna course scaling method, it is characterized in that step is as follows:

(1) aircraft rectilinear motion distance L is determined;

$L=\frac{2R}{\mathrm{\Δ}\mathrm{\α}}\·\frac{180}{\mathrm{\π}}$

Wherein, Δ α represents aircraft longitudinal axis direction course error; R represents GPS positioning precision;

(2) aircraft moves along a straight line, the drift angle α between calculating aircraft longitudinal axis course and GPS double antenna baseline course:

(2a) calculating aircraft reference position point is to the track course H of final position point _v:

Wherein, r _erepresent earth radius, represent aircraft movements starting point geographic coordinate, represent aircraft movements terminating point geographic coordinate;

(2b) drift angle between calculating aircraft longitudinal axis course and GPS double antenna baseline course:

α＝H _GPS-H _V

H _gPSrepresent GPS double antenna baseline course;

(3) aircraft is along constant with aircraft course in step (2), motion side's motion that speed is contrary, calculates the drift angle β between inertial navigation system and aircraft longitudinal axis course:

$\mathrm{\β}=\frac{l_1-l_2}{2}\×\frac{1}{L}\×\frac{180}{\mathrm{\π}}$

Wherein, l ₁when expression is moved along the direction in step (2), the aircraft lateral shift that inertial navigation system measures; l ₂when expression is moved along the direction in step (3), the aircraft lateral shift that inertial navigation system measures;

(4) drift angle, the course χ between inertial navigation system and GPS double antenna is calculated:

χ＝α+β。