KR101988266B1 - Rapid initial alignment method of slave inertial navigation system mounted on rotorcraft - Google Patents

Abstract

The present invention relates to a method for a rapid initial alignment of a slave inertial navigation system mounted on a rotorcraft. The method for the rapid initial alignment comprises: a step of performing pre-transfer alignment to estimate a non-alignment angle and time delay between a main inertial navigation system (MINS) and a slave inertial navigation system (SINS) on the basis of the speed and posture information delivered from the main inertial navigation system (MINS); a step of performing a mixed alignment in which the estimated non-alignment angle and the estimated time delay are applied to re-estimate the non-alignment angle and the time delay; and a step of removing a vibration frequency of a rotating wing using an adaptive notch filter during the performance of the pre-transfer alignment and the mixing alignment.

Description

Technical Field [0001] The present invention relates to a rapid initial sorting method of a dependent inertial navigation apparatus mounted on a rotary wing aircraft. BACKGROUND OF THE INVENTION < RTI ID = 0.0 > [0001]

The present invention relates to an inertial navigation system mounted on a flywheel aircraft and to a rapid initial alignment method of a dependent inertial navigation system included in the coronal navigation system.

The inertial navigation system is a device that provides navigation information such as position, speed, and attitude, which is navigation information of an antibody such as an airplane, ship, car, etc., using acceleration and angular velocity information measured from an accelerometer and a gyroscope, respectively. The inertial navigation system is an integral system and the error accumulates with time. Therefore, a precise initial value is required, and the process of determining the initial posture of the inertial navigation system is called initial alignment.

In order to align the SINS (Salve Inertial Navigation System) with low accuracy, the forward alignment method is mainly used among the initial sorting methods. The forward alignment method is a method of performing alignment of SINS with relatively low precision by receiving navigation information of a highly precise Master Inertial Navigation System (MINS).

However, in the case of the rotor blade aircraft platform, vibration is generated due to the rotation of the wing of the aircraft in the case of using the conventional transfer alignment, and the precision of the filter is degraded, and precision alignment accuracy can not be achieved. In addition, rapid rearrangement is required because the unaligned angle between the longitudinal inertial navigation system in the antibody and the main navigation system in the aircraft body changes due to the adjacent shot impact after the antibody firing and the internal clearance in the launch tube during the evacuation start.

The present invention is directed to solving the above-mentioned problems and other problems. Yet another object is to provide a rapid initial alignment method of a dependent inertial navigation system which is robust against vibrations caused by rotating blades of a rotorcraft aircraft and which is capable of coping with a change in the unaligned angle caused by a weapon launch and / or evasive maneuver The purpose.

The present invention relates to a rapid initial alignment method for a dependent inertial navigation system mounted on a flywheel aircraft, wherein the rapid initial alignment method comprises a main inertial navigation system based on speed and attitude information transmitted from a main navigation system (MINS) Performing a pre-transfer alignment to estimate an un-alignment angle and a time delay between a MINS and a dependent inertial navigation device (SINS); Performing a mixed alignment to prescribe an unaligned angle and a time delay by applying the estimated unaligned angle and the estimated time delay; And removing the oscillation frequency of the rotary vane using the adaptive notch filter during the pre-delivery alignment and the mixed alignment operation.

According to one embodiment, in the step of performing the mixed alignment, when the dependent inertial navigation device is installed in the launch pad inner clearance of the rotating aircraft, the horizontal unassisted angles excluding the Z axis can be re-estimated.

According to one embodiment, in performing the mixed alignment, an adaptive motion buffer may be used such that the unoriented angle estimation error caused by jittering is minimized.

According to one embodiment, when the flywheel aircraft performs the avoidance maneuver, the mixed alignment may be performed.

According to one embodiment, the adaptive notch filter may be a second infinite impulse response filter (IIR filter) that requires one parameter to estimate one sine wave.

SUMMARY OF THE INVENTION The present invention provides a rapid initial alignment method that is robust to vibrations caused by the rotating blades of a rotorcraft aircraft and is capable of responding to variations in the unassociated angles caused by weapons launch and / or avoidance maneuvers.

1 is a flowchart for explaining a rapid initial alignment method of a dependent inertial navigation device according to the present invention;
2 is a conceptual diagram for explaining a mixed alignment;

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like or similar components are denoted by the same reference numerals, and redundant explanations thereof will be omitted. The suffix "module" and " part "for the components used in the following description are given or mixed in consideration of ease of specification, and do not have their own meaning or role. In the following description of the embodiments of the present invention, a detailed description of related arts will be omitted when it is determined that the gist of the embodiments disclosed herein may be blurred. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. , ≪ / RTI > equivalents, and alternatives.

Terms including ordinals, such as first, second, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The singular expressions include plural expressions unless the context clearly dictates otherwise.

In the present application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Generally, for the initial alignment of the SINS attached to the antibody, the initial posture is obtained with the aid of the main navigation system (MINS) mounted on the aircraft body.

The procedure of the initial sorting method of the rotor blade type is shown in FIG.

First, an antibody is attached 101 to the launch tube and start maneuvering for pre-delivery alignment. The pre-delivery alignment 103 applies an adaptive notch filter 102 prior to alignment to remove the oscillation frequency of the rotary vane and then the x-axis, the x-axis, and the x-axis between the main navigation system MINS in the aircraft and the in- Y-axis, and Z-axis. Then, the estimated value is stored (104) in the memory.

Next, the pre-firing antibody is selected (105) and the adaptive notch filter (106) is performed to remove the rotating blade vibration frequency, and then the mixed alignment is performed (107). In this case, the X-axis, Y-axis, and Z-axis non-alignment angles and time delay stored through pre-alignment are used.

In systems where only horizontal unaligned angles (X and Y axes) of the dependent inertial law devices (SINS) are changed by the launch tube internal clearance, the unassisted angles of the Z axis are not re-estimated at the time of mixed alignment, .

The time delay applies the estimated value through pre-order sorting and re-estimates the change in ms. In this case, adaptive moving buffer is applied to minimize the misalignment angle estimation error caused by jittering. When the alignment is completed, the navigation 108 is performed and it is confirmed whether it is normal. After confirmation, if it is normal, select the antibody again and perform 105-108 repeatedly.

The pre-transfer alignment method is a step of pre-aligning the un-alignment angles and the time delays of the wn inertial law device (MINS) and the dependent inertial law device (SINS) to shorten the alignment time. The inertial measurement information of the reference MINS is continuously compared with the inertia measurement information of the SINS, and the transfer alignment method is used to estimate the SINS attitude through the Kalman filter. Since this method takes more than several tens of seconds, mount the antibody on the launch pad and perform it once.

Mixed alignment is a method of performing rearrangement by using pre-transfer sorting and estimating and storing the unaligned angle and time delay.

The mixed sorting method is a method in which, after outputting the speed increment and attitude increment values of the dependent inertial law apparatus (SINS) and the navigation information of the main inertial apparatus (MINS), pre-transfer sorting 202 is performed, TFA_Title_X, TFA_Tilt_Y, TFA_Tilt_Z, and TimeDelay).

When the initialization is completed, the horizontal unassigned angle and the time delay residual value that can be changed by an external factor are rapidly re-estimated 205 and the navigation information of the dependent inertial law apparatus (SINS) is updated. Therefore, precision alignment accuracy can be achieved even when the unaligned angle between the wn inertial law device (MINS) and the dependent inertial law device (SINS) changes in the case of aircraft impact avoidance and the impact of the adjacent shot after the antibody launch.

In order to apply the initial sorting method described above, it is necessary to estimate accurate un-alignment angles and time delay values. However, in the case of a rotor blade aircraft, vibration is greatly generated when the blade is rotated. Therefore, in the case of the conventional transfer alignment method, the estimation performance of the filter is degraded due to the vibration, Therefore, in order to reduce the misalignment, the influence of the rotary vane vibration must be minimized.

Accordingly, in the present invention, an adaptive notch filter is applied to reduce the influence of the rotary vane vibration. The notch filter is a filter that removes only a specific frequency and passes the rest (or vice versa). If the degree of the frequency component increases, It is possible to obtain a noise canceled signal, and to obtain a signal processing that obtains the magnitude, frequency, and phase from it.

The notch filter used is a second order IIR filter requiring only one parameter to estimate one sine wave. To remove a sine wave, you must have zero at the desired frequency and place a pole near it. Then, it removes only the frequency component corresponding to zero and passes the remaining noise components. If the signal passed through this filter is subtracted from the input, only a specific sine wave can be obtained. If the input sinusoidal wave is not known, the position of the notch, that is, the frequency of the sinusoidal wave can be estimated through the adaptation process.

라 하고 zero의 위치를

라고 하면 이 필터의 전달함수는 수학식 1과 같다.Position the pole

And the position of zero

The transfer function of this filter is expressed by Equation (1).

[Equation 1]

이다.A slight modification of this equation results in a filter such as Equation (2). here

to be.

&Quot; (2) "

를 갖는 [수학식 3]과 같은 사인파가 들어갔을 때 이 주파수를 추정하기 위해서는 필터의 출력을 최소로 하는 필터계수

를 [수학식 4]와 같은 적응 알고리즘을 통하여 찾는다.Unknown frequency

In order to estimate the frequency when a sinusoidal wave such as Equation (3) is input, the filter coefficient

Is found through an adaptive algorithm such as Equation (4).

&Quot; (3) "

&Quot; (4) "

은 all-pole 부분의 출력이며,

은 추정하고자 하는

의 시간 n에서의 추정값이고,

는 스무딩을 수행하기 전의 중간값이다.

는 기억상수,

는 스무딩 상수이다. 위에서 계수를 [-1,1] 범위로 제한함으로써 IIR 필터의 안정성을 보장할 수 있다. 계수

는 pole의 위치와 관계가 있고, pole의 위치가 사인파 입력에서 주파수

와 같은 방향으로 위 적응 알고리즘이 수렴하므로 결국 입력의 주파수

는 [수학식 5]와 같이 추정할 수 있다.here

Is the output of the all-pole portion,

Is the

Lt; RTI ID = 0.0 > n < / RTI >

Is the median value before performing the smoothing.

Is a memory constant,

Is a smoothing constant. By limiting the above coefficients to the range [-1,1], the stability of the IIR filter can be guaranteed. Coefficient

Is related to the position of the pole, and the position of the pole is the frequency

The adaptive algorithm converges in the same direction as

Can be estimated as in Equation (5).

&Quot; (5) "

On the other hand, the present invention can be implemented as a computer readable code on a medium on which a program is recorded. The computer readable medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of the computer readable medium include a hard disk drive (HDD), a solid state disk (SSD), a silicon disk drive (SDD), a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, , And may also be implemented in the form of a carrier wave (e.g., transmission over the Internet). The computer may also comprise a terminal.

Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

Claims (5)

The present invention relates to a rapid initial alignment method of a dependent inertial navigation system mounted on a rotary wing aircraft,
Performing pre-transfer sorting to estimate the unaligned angle and time delay between the main navigation system (MINS) and the dependent inertial navigation system (SINS) based on the speed and attitude information delivered from the main inertial navigation system (MINS) ;
Performing a mixed alignment to prescribe an unaligned angle and a time delay by applying the estimated unaligned angle and the estimated time delay; And
Removing an oscillation frequency of the rotary vane using an adaptive notch filter while performing the pre-delivery sorting and the mixed sorting,
In performing the mixed alignment,
Wherein an adaptive motion buffer is used to minimize the non-alignment angular error caused by jittering. The method according to claim 1,
In performing the mixed alignment,
Wherein the horizontal unassisted angles except for the Z axis are reestimated when the dependent inertial navigation system is installed in the launch pad internal clearance of the rotorcraft aircraft. delete The method according to claim 1,
Wherein the hybrid alignment is performed when the flywheel aircraft performs the avoidance maneuver. The method according to claim 1,
Wherein the adaptive notch filter is a quadratic infinite impulse response filter (IIR filter) that requires one parameter to estimate one sinusoidal wave.

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