104

DYNAMIC ATTESTATION OF METROLOGICAL CHARACTERISTICS OF AIRBORNE MEASUREMENT DEVICES

Olexander Krivonosenko1), Olha Sushchenko2), Olexander Savchenko3), Ivanna Prokofieva4)

NAU, Kyiv 03058, Kosmonavta Komarova, 1e-mails: sushoa@ukr.net , ip.willow@gmail.com, kriv.alex@ukr.net

URL: www.sula.nau.edu.ua

Abstract: Methods of dynamic attestation of basic airborne measuring instruments, which provide experimental assessment of the metrological characteristics of gyro devices in ground conditions, are considered. The necessity to create special dynamic benches, which simulate an angular motion in conditions of the real flight disturbed modes, is grounded. The results of the dynamic attestation of the unit of angular rate sensors are represented. The matrix of transfer functions of the unit of angular rate sensors is obtained. The spectral densities of the noise in the specific mode of the flight are estimated.

Key words: dynamic attestation, dynamic characteristics of sensors, matrix of transfer functions, matrix of the noise spectral densities

IntroductionComplication of the dynamic conditions and the

necessity to automate various flight modes of the modern aircraft causes the rigid requirements to accuracy of airborne measuring devices in condi-tions of the real flight.

Accuracy of the airborne measuring devices depends on both aircraft construction and nature of the flight modes. Therefore it is necessary to use test benches providing simulation of the real dynamic flight and methods of attestation of com-plex dynamic airborne measuring systems and complexes in the ground conditions.

Nowadays most of the airborne measuring de-vices are tested in the static conditions before the flight tests and operation. Only separate airborne measuring devices are sometimes tested by means of the special benches, which do not take into consid-eration conditions of the aircraft disturbed motion.

The dynamic attestation of airborne measuring devices in the ground conditions must be carried out by means of the bench-simulator or the bench-generator of the aircraft spatial angular motion in the given flight conditions [1]. Such approach will provide the closest coincidence of the real opera-tion and flight conditions. The bench-generator is able to simulate random angular three-dimensional vibrations with the statistical characteristics close to parameters of aircraft evolutions in the real flight.

The dynamic operation flight mode, which is simulated by means of the bench, represents the multidimensional stationary random process, which is characterized with a matrix of spectral densities of the output signals (aircraft angular vibrations).

1. Dynamic attestation of airborne measuring instrumentsThe metrological support of the bench-genera-

tor for determination of the tested devices dynamic characteristics must include facilities, which are able to estimate closeness of dynamics of the tested and operated flight modes [2].

The dynamic attestation of the airborne measur-ing devices lies in determination of the dynamic models of both measuring devices (transfer func-tions) and measuring noise (spectral and cospectral densities) during ground tests in the simulated dynamic conditions of the flight. The tests are carried out in all flight modes. Such approach provides obtaining measuring devices and their noise models and systematization of the dynamic attestation results.

The metrological support of the bench-genera-tor for determination of dynamic characteristics of tested devices includes the facilities for simulation of the real flight conditions.

The above stated methods use such metrological characteristics as:

- spectral densities of the noise generators, which serve as some sources of tested signals;

- frequency responses of multi-dimensional dynamic systems.

2. Simulation of angular motion by means of dynamic benchThe dynamic attestation of devices is carried out

by means of the dynamic bench, which simulates gyroscopic devices operating conditions close to

105

real ones. The block-scheme of the dynamic bench is represented in Fig. 1. The bench consists of the gimballed platform, control system, comparing unit and forming filter.

Assessment of closeness of the operation condi-tions and conditions simulated with the bench is based on comparison of the output signals of the bench and the forming filter.

The dynamic bench, which is used for simula-tion of the aircraft angular motion, mentioned bench, can be used for simulation of the aircraft angular motion. The researched unit consists of three angular rate sensors. Axes of sensitivity of these sensors are oriented along three perpendicu-lar directions. The researched unit of sensors is mounted on the platform of the dynamic bench. The platform installed in gimbals could implement the angular motion relatively to three perpendicular axes [2, 3].

Motion of the platform is provided with re-versing motors installed at every axis. The output signal of the platform represents a vector of rota-tion angles ],,[ gνy≈θ . The angular motions of the bench are transformed into the direct current signals by means of the potentiometric converters. These signals enter the control system through the forming filter.

The necessary bandwidth of frequencies is provided with the chosen feedback. The transfer functions of forming filters are defined with the dynamic characteristics. The noise generators and forming filters are realized as programs. The generator of standard signals provides calibration of the bench.

Speed of the unit of sensors mounted on the bench platform is defined in the horizontal refer-ence frame with an origin at the point O. It may be determined by the expression

ρw+= 0VV .

The vector of angular rates at the place of mounting of the unit of sensors may be calculated by the following expression

ϑyg

≈

gϑy−gϑgϑ+gϑy

ϑy+g=

www

=w

sincoscossincoscos

sin

z

y

x

p . (1)

Here g, y, ϑ are angles of the platform turns.The expression (1) does not take into consid-

eration a small displacement of the point of unit mounting relative to the point of the gimbals axes intersection.

The structural block-scheme of the unit of sen-sors is represented in Fig. 3 [1].

Fig. 1. The structural block-scheme of the laboratory plant: NG is the noise generator; FF is the forming filter; TD is the tested device; CS is the control system;

DS is the dynamic bench; CU is the comparative unit; SIP is the system of information processing

Fig. 2. The dynamic bench with tested unit

106

3. Results of experimental researchThe matrix of the spectral and cospectral densi-

ties of input and output signals could be determined based on processing of vectors of measured output

signals iw and calculated angular rates pw . The

matrix of the bench input signals 0 0

Sw w was cre-ated on the basis of experimental data and after proper processing may be approximated by the analytical expressions and represented in the fol-lowing form (2)

(2)

++

+⋅

+++−

⋅++−

+++−

⋅++−

+−++

⋅+−+

++

+

+−++

⋅+−+

+−++

⋅+−+

+++−

⋅++−

++

+⋅

−−−

−−−

−−−

2

2

3

22

3

22

3

22

32

2

3

22

3

22

3

22

32

2

3

192,142,1

10)111,4(2,0

)192,142,1)(127,163,0(

10)1673,0)(111,4(038,0

)173,107,2)(127,163,0(

10)132,2)(111,4(0361,0

)192,142,1)(127,163,0(

10)1673,0)(111,4(038,0

192,142,1

)1673,0(10

)192,142,1)(173,107,2(

116,0)1673,0)(132,2(10

)173,107,2)(127,163,0(

10)132,2)(111,4(0361,0

)192,142,1)(173,107,2(

116,0)1673,0)(132,2(10

173,107,2

)132,2(1049,0

SS

S

SSSS

SS

SSSS

SS

SSSS

SS

SS

S

SSSS

SS

SSSS

SS

SSSS

SS

SS

S

The plots of the spectral and cospectral densi-ties of input signals are given in Figs 4, 5.

The obtained information represents the data necessary for identification of the airborne meas-uring instruments. For determination of dynamic models of the airborne measuring instruments and measurement noise the modernized algorithm of the structural identification was used [4]. The al-gorithm uses Wiener-Kolmogorov procedure as a basis and helps to determine model of the system due to minimization of its quality functional.

The matrix of the transfer functions is deter-mined after substitution of the initial data into the algorithm of structural identification, mentioned above. The resultant matrix of the transfer func-tions looks like

SeKK 0

0,109,007,009,00,106,007,006,00,1

0t−

w ⋅

= . (3)

Here 0K is the transfer coefficient; 0t is the time delay defined by features of the transmission channels.

Taking into consideration the cross-connec-tions, the matrix of the transfer functions of a certified unit (3) may be represented in the fol-lowing form

Fig. 3. The block-scheme of the unit of sensors:

pw is the vector of the calculated input signals; w is the vector of output signals;

j is the vector of noise

Fig. 4. Spectral density of input signals

10-2

10-1

100

101

10-9

10-8

10-7

10-6

Frequency, rad/sec

S

w eKKKKK

KKKKKKKKKK

K 0

33231

31221

31211

3,005,003,004,08,005,002,001,02,1

t−⋅

=

(4)

Here iK are transfer coefficients of measuring channels.

The matrices of the spectral densities of the noise at the tested unit output becomes

Se

SS

SS

SS

S 000

21

1,01

1,01

1,011

4,01

1,01

4,01

10

22

22

22

5 t−−wyy ⋅

+t+t

+t+t

+t+t

= . (5)

107

Here 0t is the time constant defined by features of transmission channels.

The plot of the cospectral density of the meas-urement noise is represented in Fig. 6.

Represented results were obtained based on the initial information for identification of measuring device dynamic models. For this it is necessary to use the algorithm for the structural identification of dynamic models of the measuring device and the measurement noise.

Fig. 6. Cospectral density of the measurement noise

4. ConclusionsThe obtained results of the model dynamic at-

testation are necessary for the effective solution of the actual and complex scientific-technical prob-lems of the aviation engineering such as optimal estimation of the state of the measuring devices and their identification, analysis and synthesis of the flight control systems and automatic aviation systems, correction of the aircraft control systems during operation, creation of the systems for on-line dynamic check of control quality.

The measurement assurance of the bench-generator for determination of the tested devices dynamic characteristics must include means for simulation of the flight operation conditions.

Dynamic characteristics of the airborne meas-

uring devices and measuring noise are necessary in order to check the gyro devices before their mounting at aircraft.

Determination of the gyro devices noise char-acteristics in the specific operation modes is neces-sary for accurate determination of the location and attitude of aircraft in the inertial space

The obvious results of the experimental re-searches are the matrix of the measuring device transfer functions (4) and the matrix of spectral and cospectral densities of measurement noise (5) obtained by means of approximations of the graphi-cal information with the analytical expressions.

Usage of the obtained results for modernization of the airborne measurement device allows increas-ing the accuracy of measured stochastic parameters of the aircraft motion.

Analysis of dynamic models allows making the following conclusions:

- the certified unit of sensors has significant cross-connections between measuring channels;

- elements of the noise vector are strongly cor-related with each other;

- the high-precision algorithms of navigation information processing require to take into consid-eration the cross-connections of models.

So, usage of the obtained results allows increas-ing measuring accuracy of the aircraft stochastic parameters.

5. References[1] L.N. Blokhin, M. Yu. Burichenko, A.P.

Krivonosenko. Identification of models of dynam-ics of blocks of sensitive elements of SINS. IEEE Journal of Avtomation and Information Sciences, vol. 30, no. 6, 1998, P. 64-71.

[2] Krivonosenko O.P., Savinov O.M., Sush-chenko O.A. Methodologia ta resultati viznachen-nya dinamichnikh kharasteristik kutovogo zbure-nogo rukhu litalnogo aparata. Visnik NAU, no. 4, 2002, P. 76 – 80.

[3] Blokhin L.N., Derzhak S.V., Sushchenko O.A. Dynamicheskaya atestatsia bortovikh izmeriteley v usloviyakh priblizhenikh k eksplu-atatsionim. Technichna electrodinamika. Special issue. “Problemi suchasnoi elektrotechniki”, part 9, 2002, P. 59 – 62.

[4] L.N. Blokhin, A.P. Krivonosenko. Prob-lem and algorithms of structural identification of unstable vehicles. IEEE 2nd International Confer-ence Actual Problems of Unmanned Air Vehicles Development, October 15–17, 2013. P. 173-175, Kyiv, Ukraine.

10-2

10-1

100

101

10-8

10-6

10-4

10-2

10-2

10-1

100

101

-30

-20

-10

0

Frequency, rad/sec

Fig. 5. Cospectral density of input signals

108

Information about the Authors:Krivonosenko Olexander Petrovich.National Aviation University (1982). Cand. of

Sc. (Eng.) (1989), associated professor (1991); National Aviation University, Aircraft Control Systems Department. Scientific interests: dynamic attestation.

Sushchenko Olha AndriivnaKyiv Polytechnic Institute (1980). Cand. of Sc.

(Eng.) (1991), associated professor (2003); Doct. of Sc. (Eng) (2015). National Aviation University, Aircraft Control Systems Department. Scientific

interests: dynamic systems.Savchenko Olexander ValentinovichNational Aviation University (2010). Post-

graduated student. National Aviation University, Aircraft Control Systems Department. Scientific interests: Dynamic attestation.

Prokofieva Ivanna YurievnaNational Aviation University (2002). Assistant.

National Aviation University, Aircraft Control Systems Department. Scientific interests: Dynamic attestation.

ДИНАМИЧЕСКАЯ АТТЕСТАЦИЯ МЕТРОЛОГИЧЕСКИХ ХАРАКТЕРИСТИК

БОРТОВЫХ ИЗМЕРИТЕЛЬНЫХ ПРИБОРОВ

Александр Кривоносенко1), Ольга Сущенко2), Александр Савченко3), Иванна Прокофьева4) НАУ, Киев 03058, пр-т Космонавта Комарова, 1

e-mail: sushoa@ukr.net , ip.willow@gmail.com, kriv.alex@ukr.net URL: www.sula.nau.edu.ua

Резюме: Рассмотрены методы динамической аттестации основных бортовых измерительных устройств, позволяющие экспериментально оценить метрологические характеристики гироскопических приборов в наземных условиях. Обоснована необходимость создания специальных динамических стендов для имитации угловых движений объекта в условиях реального возмущенного полета. Представлены результаты динамической аттестации блока датчиков угловых скоростей в виде его матрицы передаточных функций. Также оценены спектральные плотности шума в конкретном режиме полета.

Ключевые слова: динамическая аттестация, динамические характеристики датчиков, матрица передаточных функций, матрица спектральных плотностей шума

ДИНАМИЧНА АТЕСТАЦИЯ НА МЕТРОЛОГИЧНИТЕ ХАРАКТЕРИСТИКИ НА БОРДОВИТЕ ИЗМЕРВАТЕЛНИ УРЕДИ

Александр Кривоносенко1), Ольга Сущенко2), Александр Савченко3), Иванна Прокофьева4) НАУ, Киев 03058, пр-т Космонавта Комарова, 1

e-mail: sushoa@ukr.net , ip.willow@gmail.com, kriv.alex@ukr.net URL: www.sula.nau.edu.ua

Резюме: Разгледани са методите за динамична атестация на основните бордови измервателни устройства, позволяващи експериментално да се оценят метрологичните характеристики на жироскопичните уреди в наземни условия. Обоснована е необходимостта от създаване на специални динамични стендове за имитация на ъглови движения на обекта в условията на реален смущаван полет. Представени са резултатите от динамична атестация на блока на сензорите на ъглови скорости във вид на негова матрица на предавателните функции. Също така са оценени спектралните плътности на шума в конкретния режим на полет.

Ключови думи: динамична атестация, динамични характеристики на сензори, матрица на предавателните функции, матрица на спектралните плътности на шума.