CN101706283B - Method for transonic shock wave interference adaptive suppression of altitude channel - Google Patents

Abstract

The invention discloses a method for transonic shock wave interference adaptive suppression of an altitude channel, belonging to the field of inertia/atmosphere combination navigation. In the invention, an inertial navigation altitude and an atmosphere altitude are solved according to the principles of an inertia navigation system and an atmosphere data system. When transonic section static pressure fluctuation causes atmospheric pressure altitude fluctuation, an adaptive wave filter is utilized to treat a difference value of the atmospheric pressure altitude or the inertial navigation altitude and the atmospheric pressure altitude, and the wave filter outputs corresponding shock wave interference signals; the shock wave interference signals are fed back, and subtract the atmospheric pressure height so as to cancel shock wave interference, or the shock wave interference signals subtract the static pressure after unit conversion so as to cancel the shock wave interference; and an adaptive algorithm is utilized, the adaptive wave filter is regulated according to a altitude difference value of the atmospheric pressure altitude and the inertial navigation altitude, the altitude difference value revises the inertial navigation altitude through an altitude channel damping loop, and a combination altitude for suppressing the shock wave interference is obtained, thereby cancellation and suppression of altitude channel transonic shock wave interference signals are realized. The invention provides stable and reliable attitude information with high accuracy for an aircraft, enhances the navigation control accuracy of the aircraft and improves the operation performance of the aircraft.

Description

The method for transonic shock wave interference adaptive suppression of altitude channel

Technical field

The present invention is a kind of inhibition method that the altitude channel shock wave disturbs when being applied to aircraft transonic flight, belongs to inertia/atmosphere integrated navigation field.

Background technology

Inertial navigation system and air data system are widely used navigational system in the present generation aircraft.Inertial navigation system is an a kind of high-precision self-aid navigation system, rely on airborne equipment independently to finish navigation task fully, any light, electrical communication do not take place with the external world, so good concealment, work is not subjected to the restriction of meteorological condition, have round-the-clock and ability worldwide navigation, the navigational parameters such as position, speed, attitude, acceleration and angular velocity of carrier can be provided.Air data system is a kind of airborne Integrated Measurement System of multiple-input and multiple-output, it is by the acting force between atmospheric parameter instrument measurement aircraft and atmosphere and the atmosphere data (as atmospheric pressure, temperature etc.) of aircraft location, resolve through air data computer again, can access the angle of attack, highly, flight navigation information such as Mach number, rising or falling speed.

When working independently, inertial navigation system has deficiency, its altitude channel instability, and height error spreads.Therefore can not directly adopt the altitude channel of pure inertia, usually introduce external height information (air data system etc.) altitude channel is constituted damping circuit, make two kinds of elevation informations play complementation, can learn from other's strong points to offset one's weaknesses in such two aspects, obtain the combined altitudes system that dynamic quality is good and error is not dispersed in time, adopt second order damping or three rank damping circuits usually.But this method only is applicable to general flying condition, and when aircraft transonic flight, because extraneous shock wave disturbs, the static pressure that causes air data system to record produces fluctuation, and then makes the barometer altitude after resolving produce fluctuation.The barometer altitude signal entry altitude passage damping circuit of fluctuation finally makes combined altitudes produce fluctuation, and this moment, not only the atmosphere elevation information was unavailable, also the effect of utilizing the atmosphere elevation information to carry out the damping of inertial navigation altitude channel was had a negative impact.

Summary of the invention

The present invention seeks to provide a kind of method for transonic shock wave interference adaptive suppression of altitude channel at the defective that prior art exists, improve existing the utilization in the atmosphere height damping inertial navigation altitude channel method, the deficiency of fluctuation appears in combined altitudes during transonic flight, utilize the output data of airborne inertial navigation system and air data system, in conjunction with altitude channel damping algorithm, exploration is applicable to the new way of transonic inertia/atmosphere altitude channel calculation method, for aircraft provides steadily, reliable, accurate elevation information.

The present invention adopts following technical scheme for achieving the above object:

The method for transonic shock wave interference adaptive suppression of altitude channel of the present invention is characterized in that comprising the steps:

1) Inertial Measurement Unit signals collecting: gather the output signal of accelerometer in the Inertial Measurement Unit, obtain the ratio force information of inertial navigation system;

2) the inertial navigation system inertial navigation is highly resolved: inertial navigation system inertial navigation height h is by acceleration

Twice integration obtains, and has in the altitude channel: ${\stackrel{\·}{v}}_z^n=f_z^n+({2\mathrm{\ω}}_{\mathrm{ie}}\cos L+\frac{v_x^n}{R_n})v_x^n+\frac{v_y^n}{R_m}{v}_y^n-g=f_z^n+a_{\mathrm{Be}}-g,$ Wherein

Be carrier short transverse acceleration under navigation system, v _x ⁿ, v _y ⁿBe respectively carrier east orientation, north orientation speed under navigation system, f _z ⁿBe short transverse specific force under the navigation system, ω _IeBe rotational-angular velocity of the earth, L is place, carrier place latitude, R _m, R _nBe respectively meridian circle, the prime vertical latitude is the radius-of-curvature at L place, g is place, carrier place acceleration of gravity;

3) the air data system barometer altitude is resolved: under standard atmosphere condition, and barometer altitude H _pBe static pressure P _sFunction, according to the standard pressure altitude formula, have

$H_p=145442[1-{\left(\frac{P_s}{29.9213}\right)}^{0.19026}],$ H _p＜36089 feet

$H_p=36089-20806\left[\ln \left(\frac{P_s}{6.68324}\right)\right],$ 36089 feet≤H _p＜65617 feet;

4) auto adapted filtering of elevation information, comprise following two kinds of methods: a) when the transonic speed initial stage, static pressure generation fluctuation caused that fluctuation appears in the barometer altitude signal, with inertial navigation height and the input of the barometer altitude difference that fluctuates as sef-adapting filter, the shock wave undesired signal of wave filter output height difference; Described shock wave undesired signal feedback and barometer altitude are done difference offset shock wave and disturb, or described shock wave undesired signal is carried out unit conversion back and static pressure do difference and offset shock wave and disturb, resolve the barometer altitude behind the corresponding shock wave interference cancellation; Eliminate barometer altitude that shock wave disturbs and highly do difference with inertial navigation and obtain height difference, according to height difference and utilize adaptive algorithm, progressively adjust sef-adapting filter, constantly adjusting reduces height difference; B) when fluctuation appears in transonic speed initial stage barometer altitude signal, with the barometer altitude of fluctuation as the input of sef-adapting filter, the shock wave undesired signal of wave filter output pressure height, and shock wave undesired signal and barometer altitude are done difference offset shock wave and disturb, or the shock wave undesired signal is done through unit conversion and static pressure poor, static pressure is revised, adopt the barometer altitude of revising after the back static pressure calculates corresponding shock wave interference cancellation; Eliminate barometer altitude that shock wave disturbs and highly do difference with inertial navigation and obtain height difference, according to height difference and utilize adaptive algorithm, progressively adjust sef-adapting filter, constantly adjusting reduces height difference;

5) inertial navigation altitude channel damping algorithm: the damping algorithm adopts second order damping or three rank dampings, above-mentioned height difference is pressed second order damping or three rank damping algorithm process, feed back to the inertial navigation altitude channel of step (2), realization is to the control of altitude channel, and the inertial navigation in the inertial navigation this moment altitude channel damping circuit is highly exported to be and suppressed the combined altitudes information that transonic shock wave disturbs.

The present invention's actual performance demand of elevation information from the aircraft flight parameter is started with, essence based on the inertial navigation system altitude channel, the principle of resolving in conjunction with airborne air data system elevation information, by collection to inertial navigation system specific force and atmosphere static pressure, real-time resolving inertial navigation height and barometer altitude, by the adaptive filter algorithm that transonic shock wave in barometer altitude or the air pressure signal is disturbed, and altitude channel damping algorithm, the inhibition that realization is disturbed aircraft transonic speed altitude channel shock wave, and then the fluctuation of altitude signal when reducing transonic speed, for aircraft provides high precision and steadily reliable elevation information, improve the Navigation Control precision of aircraft, improve the handling of aircraft.

The present invention has very strong engineering using value.

Description of drawings

Fig. 1 offsets the algorithm principle block diagram based on the self-adaptation shock wave undesired signal of height error time-frequency characteristic.

Fig. 2 offsets the algorithm principle block diagram based on the self-adaptation shock wave undesired signal of barometer altitude time-frequency characteristic.

The pure inertial navigation altitude channel of Fig. 3 theory diagram.

Fig. 4 sef-adapting filter theory diagram.

Fig. 5 inertial navigation altitude channel second order damping circuit theory diagram.

Fig. 6 inertial navigation altitude channel three rank damping circuit theory diagrams.

Embodiment

Be elaborated below in conjunction with the technical scheme of accompanying drawing to invention:

Under the general flying condition, utilize the barometer altitude damping inertial navigation system altitude channel of air data system both can suppress pure inertial navigation dispersing highly in time, can obtain the higher combined altitudes of precision again.But under transonic condition, because shock wave disturbs, make barometer altitude produce fluctuation, and then cause the fluctuation of combined altitudes.The present invention improves on altitude channel damping circuit basis commonly used, as shown in Figure 1 and Figure 2, resolve inertial navigation height and atmosphere height according to inertial navigation system and air data system principle, when transonic speed section static pressure fluctuation causes the barometer altitude fluctuation, utilize sef-adapting filter to handle the difference of barometer altitude or inertial navigation height and barometer altitude, the corresponding shock wave undesired signal of wave filter output.Shock wave undesired signal feedback and barometer altitude are done the poor shock wave interference that offsets, or the shock wave undesired signal is carried out unit conversion back do the poor shock wave interference that offsets with static pressure.Utilize adaptive algorithm, height difference according to barometer altitude and inertial navigation height is adjusted sef-adapting filter, height difference is through altitude channel damping circuit correction inertial navigation height, the combined altitudes that the shock wave that has been inhibited disturbs, thus realize the inhibition of offseting of altitude channel transonic shock wave undesired signal.

In order to finish the Adaptive Suppression that the altitude channel shock wave disturbs under the transonic condition, need finish the work:

1 Inertial Measurement Unit signals collecting step

Gather the output signal of accelerometer in the Inertial Measurement Unit, obtain the ratio force information of inertial navigation system.

Step is highly resolved in 2 inertial navigation system inertial navigations

Inertial navigation system inertial navigation height h is by acceleration Twice integration obtains, and has in the altitude channel

${\stackrel{\·}{v}}_z^n=f_z^n+(2{\mathrm{\ω}}_{\mathrm{ie}}\cos L+\frac{v_x^n}{R_n})v_x^n+\frac{v_y^n}{R_m}{v}_y^n-g=f_z^n+a_{\mathrm{Be}}-g---\left(1\right)$

Wherein

Be carrier short transverse acceleration under navigation system, v _x ⁿ, v _y ⁿBe respectively carrier east orientation, north orientation speed under navigation system, f _z ⁿBe short transverse specific force under the navigation system, ω _IeBe rotational-angular velocity of the earth, L is place, carrier place latitude, R _m, R _nBe respectively meridian circle, the prime vertical latitude is the radius-of-curvature at L place, g is place, carrier place acceleration of gravity.G is not normal value but the function of height h in the precision navigation, and its numerical value reduces with increase highly, when h＜＜during R, have

$g=g_0(1-\frac{2h}{R})---\left(2\right)$

Wherein R is an earth radius, g ₀Be earth surface acceleration of gravity.Can draw the theory diagram of pure inertial navigation altitude channel by formula (1), as shown in Figure 3.

3 air data system atmosphere height resolve step

Barometer altitude (H _p) (being flying height) relevant with temperature (t) with the pressure (P) of atmosphere.Under the normal atmosphere situation, barometer altitude becomes following funtcional relationship with atmospheric parameter:

H _p＝f(P _s，P _b，t _b，τ _b) (3)

P in the formula _b---under the normal atmosphere situation, each corresponding atmospheric low pressure limit value (Pa);

t _b---under the normal atmosphere situation, each corresponding atmospheric lowest temperature value (℃);

τ _b---under the normal atmosphere situation, each corresponding atmospheric thermograde (℃/km);

For normal atmosphere, P _b, t _b, τ _bIt all is standard value.Therefore, as long as can measure the atmosphere static pressure P of aircraft place height _S, just can try to achieve the barometer altitude of aircraft according to the standard pressure formula.

According to the standard pressure altitude formula, have

$H_p=145442[1-{\left(\frac{P_s}{29.9213}\right)}^{0.19026}],$ H _p＜36089 feet (4)

$H_p=36089-20806\left[\ln \left(\frac{P_s}{6.68324}\right)\right],$ 36089 feet≤H _p＜65617 feet (5)

Under standard atmosphere condition, height H _pBe static pressure P _SFunction.

The auto adapted filtering step of 4 elevation informations

This step adopts two kinds of schemes to realize.

First kind of scheme as shown in Figure 1, when the transonic speed initial stage, static pressure generation fluctuation caused that fluctuation appears in the barometer altitude signal, with inertial navigation height and the input of the barometer altitude difference that fluctuates as sef-adapting filter, the shock wave undesired signal of wave filter output height difference, and the shock wave undesired signal fed back, do poorly with barometer altitude, revise barometer altitude; Or the shock wave undesired signal is done poor through unit conversion and static pressure, and revise static pressure, calculate corresponding barometer altitude.Revised barometer altitude has been eliminated the shock wave interference, itself and inertial navigation are highly done difference and are obtained height difference, according to height difference and utilize adaptive algorithm, progressively adjust sef-adapting filter parameter (filter order and filtering step-length etc.), make performance of filter do the self-adaptation adjustment with the variation of height difference, constantly adjusting reduces height difference;

Second kind of scheme as shown in Figure 2, when fluctuation appears in transonic speed initial stage barometer altitude signal, with the barometer altitude of fluctuation as the input of sef-adapting filter, the shock wave undesired signal of wave filter output pressure height, and shock wave undesired signal and barometer altitude done barometer altitude after difference obtains the shock wave interference cancellation; Or the shock wave undesired signal is done poor through unit conversion and static pressure, and static pressure is revised, revise the barometer altitude after the back static pressure calculates corresponding shock wave interference cancellation.Eliminate the barometer altitude and the inertial navigation of shock wave interference and highly do the poor height difference that obtains, according to height difference and utilize adaptive algorithm, progressively adjust sef-adapting filter parameter (filter order and filtering step-length etc.), make performance of filter do the self-adaptation adjustment with the variation of height difference, constantly adjusting reduces height difference.

Sef-adapting filter adjusts automatically at any time filter parameter by the adaptive algorithm of being controlled by error, lowest mean square (LMS, Least Mean Square) algorithm is a kind of linear adaption algorithm that is most widely used now, it is a criterion with mean square of error value minimum between Expected Response and the filter output signal, in iterative process, estimate gradient vector according to input signal, and upgrade weight coefficient to reach efficient adaptive iterative algorithm.It does not need relevant related function and matrix inversion operation, is a kind of useful and simple algorithm.

The LMS algorithm generally comprises two basic processes: one is filtering, and another is an adaptive process.In filtering, sef-adapting filter calculates its response to input, and by comparing the error signal that obtains estimating with Expected Response.In adaptive process, the system estimation error is adjusted the parameter of wave filter self automatically.Feedback loop of the common composition of these two processes, as shown in Figure 4.Among the figure, the error signal of sef-adapting filter is

e(n)＝d(n)-y(n)(6)

In the formula, e (n) is a n error signal constantly, and d (n) is a n wanted signal constantly, and y (n) is the n output signal of sef-adapting filter constantly, is expressed as

y(n)＝x ^T(n)w(n)＝w ^T(n)x(n)(7)

X in the formula (n) is a n input signal vector constantly, and it is defined as x (n)=[x (n) x (n-1) ... x (n-M)] ^T(single input structure, M are delay time) or x (n)=[x ₀(n) x ₁(n) ... x _M(n)] ^T(many input structures, M are the input signal number), w (n) is a n weight vectors constantly.

The LMS algorithm carry out the gradient estimation approach with error signal each time the instantaneous square value of iteration substitute its mean square value, and estimate gradient, promptly with this

$\widehat{\▿}\left(n\right)={\left[\begin{array}{cccc}\frac{{\∂e}^2\left(n\right)}{{\∂w}_0\left(n\right)}& \frac{{\∂e}^2\left(n\right)}{{\∂w}_1\left(n\right)}& \·\·\·& \frac{{\∂e}^2\left(n\right)}{{\∂w}_M\left(n\right)}\end{array}\right]}^T---\left(8\right)$

In the formula

Be the gradient estimated value, (8) formula is had if write as vector form

$\widehat{\▿}\left(n\right)=\frac{{\∂e}^2\left(n\right)}{\∂w\left(n\right)}---\left(9\right)$

With formula (6) and formula (7) substitution formula (9), obtain

$\widehat{\▿}\left(n\right)=2e\left(n\right)\frac{\∂e\left(n\right)}{\∂w\left(n\right)}=-2e\left(n\right)x\left(n\right)---\left(10\right)$

In method of steepest descent, have

$w(n+1)=w\left(n\right)-\mathrm{\μ}\▿\left(n\right)---\left(11\right)$

μ is the converging factor of control speed of convergence and stability in the formula,

Be the gradient true value.Use the gradient valuation

Substitute the gradient true value in the method for steepest descent

, have

$w(n+1)=w\left(n\right)+\mathrm{\μ}(-\widehat{\▿}\left(n\right))=w\left(n\right)+2\mathrm{\μe}\left(n\right)x\left(n\right)---\left(12\right)$

Formula (12) is the wave filter weight vector iterative formula of LMS algorithm, and next weight coefficient vector constantly of adaptive iteration can be added with the error function to be that the input vector of scale factor obtains by the weight coefficient vector of current time.5 inertial navigation altitude channel damping algorithm steps

Inertial navigation altitude channel damping algorithm can adopt damping of existing altitude channel second order or three rank damping algorithms, and (theory diagram is respectively as Fig. 5, shown in Figure 6), or on existing second order or damping circuit basis, three rank, improved, the inertial navigation height and the difference of barometer altitude are pressed certain damping algorithm process, feed back to the acceleration of step (2) inertial navigation altitude channel through damping circuit, speed or inertial navigation are highly located, under the prerequisite that guarantees total system stability, according to the parameter in the relation adjustment damping circuit of control principle, realization is to the control of altitude channel, and the inertial navigation in the inertial navigation this moment altitude channel damping circuit is highly exported to be and suppressed the combined altitudes information that transonic shock wave disturbs.

Claims (1)

1. the method for transonic shock wave interference adaptive suppression of an altitude channel is characterized in that comprising the steps:

1) Inertial Measurement Unit signals collecting: gather the output signal of accelerometer in the Inertial Measurement Unit, obtain the ratio force information of inertial navigation system;

2) the inertial navigation system inertial navigation is highly resolved: inertial navigation system inertial navigation height h is by acceleration

Twice integration obtains, and has in the altitude channel:

Wherein Be carrier short transverse acceleration under navigation system, v _x ⁿ, v _y ⁿBe respectively carrier east orientation, north orientation speed under navigation system, f _z ⁿBe short transverse specific force under the navigation system, ω _IeBe rotational-angular velocity of the earth, L is place, carrier place latitude, R _m, R _nBe respectively meridian circle, the prime vertical latitude is the radius-of-curvature at L place, g is place, carrier place acceleration of gravity;

3) the air data system barometer altitude is resolved: under standard atmosphere condition, and barometer altitude H _pBe static pressure P _sFunction, according to the standard pressure altitude formula, have

H _p＜36089 feet

36089 feet≤H _p＜65617 feet;

4) auto adapted filtering of elevation information, comprise following two kinds of methods: a) when the transonic speed initial stage, static pressure generation fluctuation caused that fluctuation appears in the barometer altitude signal, with inertial navigation height and the input of the barometer altitude difference that fluctuates as sef-adapting filter, the shock wave undesired signal of wave filter output height difference; Described shock wave undesired signal feedback and barometer altitude are done difference offset shock wave and disturb, or described shock wave undesired signal is carried out unit conversion back and static pressure do difference and offset shock wave and disturb, resolve the barometer altitude behind the corresponding shock wave interference cancellation; Eliminate barometer altitude that shock wave disturbs and highly do difference with inertial navigation and obtain height difference, according to height difference and utilize adaptive algorithm, progressively adjust sef-adapting filter, constantly adjusting reduces height difference; B) when fluctuation appears in transonic speed initial stage barometer altitude signal, with the barometer altitude of fluctuation as the input of sef-adapting filter, the shock wave undesired signal of wave filter output pressure height, and shock wave undesired signal and barometer altitude are done difference offset shock wave and disturb, or the shock wave undesired signal is done through unit conversion and static pressure poor, static pressure is revised, adopt the barometer altitude of revising after the back static pressure calculates corresponding shock wave interference cancellation; Eliminate barometer altitude that shock wave disturbs and highly do difference with inertial navigation and obtain height difference, according to height difference and utilize adaptive algorithm, progressively adjust sef-adapting filter, constantly adjusting reduces height difference;

5) inertial navigation altitude channel damping algorithm: the damping algorithm adopts second order damping or three rank dampings, above-mentioned barometer altitude and inertial navigation are highly done the poor height difference that obtains by second order damping or three rank damping algorithm process, feed back to the inertial navigation altitude channel of step (2), realization is to the control of altitude channel, and the inertial navigation in the inertial navigation this moment altitude channel damping circuit is highly exported to be and suppressed the combined altitudes information that transonic shock wave disturbs.

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