RU2461801C1 - Method of determining wind speed aboard aircraft and integrated navigation system for realising said method - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: method of determining wind speed aboard aircraft is based on measuring airspeed of the aircraft and calculating the path travelled by the aircraft in air, measuring ground speed and/or current coordinates of the aircraft using any methods, comparing the ground speed with the airspeed and/or current coordinates of the aircraft with coordinates obtained by calculation, and integrating the obtained difference signals on speed and/or coordinates, in which before integration, the result of comparing speeds and/or coordinates is changed in a function of current values of the heading and speed of the aircraft, and the determination of wind speed itself is carried out directly as the aircraft manoevres on the heading. The apparatus which realises the method of determining wind speed, having interconnected sensors for air speed, angles of attack and yaw, the heading and elevation, ground speed and coordinates, a unit for determining relative velocity vector components, four integrators, nine adders, additionally includes a unit for generating correcting signals and a fifth integrator.

EFFECT: high accuracy of determining wind speed aboard aircraft.

2 cl, 3 dwg

Description

The proposed method and integrated navigation system relate to the field of aviation instrumentation and can be used in the development of navigation equipment for aircraft.

The airborne method of reckoning is widely used in aircraft navigation systems (Seleznev V.P. Navigation Devices, Moscow: Mashinostroenie, 1974, chap. X).

To ensure greater accuracy in determining the coordinates of the position in the course of flight time reckoning and when solving many functional problems on board the aircraft, you must have information about the speed and direction of the wind.

Theoretical and practical aspects of the operation of on-board equipment, providing the determination and use of wind speed on board the aircraft, are given in the following works:

1. Vorobyov L.M. Air Navigation, Moscow: Engineering, 1984.

2. Kirst M.A. Navigation flight cybernetics. M .: Military Publishing, 1971.

3. Pomykaev I.I., Seleznev V.P., Dmitrochenko L.A. Navigation devices and systems. M .: Engineering, 1983.

4. Rivkin S.S., Ivanovsky R.I., Kostrov A.V. Statistical optimization of navigation systems. L .: Shipbuilding, 1976.

5. Rogozhin V.O., Sineglazov V.M., Fiyashkin M.K. Flight and navigation complexes of used ships. K .: Knizhkov vidavnitstvo NAU, 2005 (in Ukrainian).

6. Seleznev V.P. Navigation devices. M .: Mechanical Engineering, 1974.

7. Reference pilot and navigator of civil navigation. Edited by Vasin I.F. M .: Transport, 1988.

Wind speed and direction are usually set with the help of a commander according to commands from the ground or are determined on board the aircraft in some indirect way (see [6], chap. X; [2], chap. VII; [5], chap. 7; [7], Ch. 9). Measurement of wind speed and direction directly on board the aircraft is more preferable, because allows you to constantly clarify their values in the area of the aircraft.

The book [6] on page 276 describes a method of measuring wind speed on board an aircraft, in which the speed and direction of wind in flight are obtained by comparing the coordinates of the aircraft X _B , Y _B obtained by reckoning the path relative to air and the coordinates of the actual location of the aircraft, measured any of the known methods of orientation (visual, astronomical, radio engineering, etc.) X, Y.

The components of the wind speed in the earth's coordinate system are:

,

,

,

,

where t is the dead reckoning time.

A specific example of the implementation of this method in aviation equipment can be the combined navigation system described in the book [2] on pages 131-135. In this system, as the integral errors of the system, using the data of radio measurements, the errors of the airspeed sensor and the heading sensor are determined, including the components of the wind speed vector:

which fundamentally does not prevent us from considering this system as determining the components of wind speed in the Earth’s geographic coordinate system

In the book [6] on pages 546-556, an example of a course air-Doppler navigation system describes a method of measuring wind speed, in which the speed and direction of wind in flight is determined by comparing the speed of the aircraft relative to air V _B , measured by the aerometric method, with ground speed of the aircraft W, measured by the radio-technical Doppler method. In principle, any method for measuring ground speed W can be used to determine wind speed, for example, inertial or currently widely used radio-technical satellite.

We believe that in both cases the same method for determining the wind speed is described, based on measuring the parameters of the movement of the aircraft relative to the air and comparing them with similar parameters of the movement of the aircraft relative to the surface of the earth.

This method, as the closest to the proposed, is selected as a prototype.

At the same time, taking into account that the ground speed measuring device and the actual location of the aircraft, for example, radio engineering systems (DISS - Doppler speed and drift measuring device, SNA - satellite navigation system, RSBN - short-range radio engineering system, RSDN - long-range radio-technical system) have random errors, having a high-frequency nature, we believe that the method involves the statistical filtering of these errors.

As already mentioned above, the system described in the book [2] on pages 131-135, can be considered as determining the components of the wind speed in the Earth’s geographic coordinate system:

where X _E , Y _N are the measured coordinates of the actual location of the aircraft in the geographical coordinate system, and the coordinates X _EB , Y _NB are obtained by calculating the horizontal components of the airspeed vector V _EB , V _NB in the geographical coordinate system relative to the coordinates of the initial location of the aircraft X _E0 , Y _N0 :

V _EB = V _XГ sinΨ + V _ZГ cosΨ + U _E ,

V _NB = V _XГ cosΨ + V _ZГ sinΨ + U _N ,

V _XГ , V _ZГ - components of the airspeed vector in a horizontal airplane coordinate system:

V _XГ = V _AND (cosϑ + α _АТ sinϑcosγ + β _CK sinϑsinγ),

V _ZГ = V _AND (β _CK cosγ-α _AT sinγ),

V _И is the longitudinal component of the airspeed vector measured by the airspeed sensor, α _АТ , β _CK are the angles of attack and slip, measured by the sensors of the angle of attack and the angle of slip, Ψ, γ, υ are the course, roll, pitch, measured by the inertial vertical direction.

A specific example of the implementation of the prototype method in aircraft, using data on the ground speed of the aircraft, can serve as the aforementioned course-air-Doppler navigation system described in the book [6], on pages 546-556.

In the system described in the book in the book [6], on pages 546-556, the components of the wind speed in the geographical coordinate system are determined by integrating the results of comparing the components of the directional vectors W _E , W _N and air speed V _EB , V _NB :

The velocity components measured by the prototype method will be determined with large errors, because they include a component due to an error in the airspeed sensor.

U _{E *} = U _E + ΔU _EV ,

U _N = U _N + ΔU _NV ,

where ΔU _EV , ΔU _NV are the errors in the determination of the components of the wind speed on the corresponding axes, due to the error of the airspeed sensor, U _X , U _Y are the real components of the wind speed vector.

Constant coefficients K ₁ and K ₂ are usually selected from the condition of minimum mean square error in coordinates and speed.

Since the errors of the airspeed vector meters are associated with the aircraft coordinate system, and the wind with the Earth coordinate system, navigation systems that use the prototype method for measuring wind most effectively work when flying with the same heading, when the position of the aircraft coordinate system relative to the Earth does not change .

If the aircraft makes a maneuver at the heading, then the wind speed vector, measured previously by the prototype method, its measurement errors due to the error of the airspeed sensor, introduce additional errors in the calculated coordinates, because they are deployed together with the aircraft coordinate system, but continue to be taken into account in the components of the wind speed vector, determined with a different relationship of the earth and aircraft coordinate systems.

Since information on wind speed is used in solving many problems on board an aircraft, the accuracy of data on wind speed is of significant independent significance.

The aim of the invention is to improve the accuracy of measuring wind speed and expand the functionality of the method by separately determining the components of the vector of wind speed and the error of the airspeed sensor in the maneuver sections at the rate at which the relative position of the axes of the earth coordinate system and the aircraft coordinate system in which the air sensor works speeds vary.

This goal is achieved by the fact that in the method of measuring wind speed on board an aircraft based on measuring the angular orientation and speed relative to air, reckoning the distance traveled relative to air, measuring the ground speed and / or location coordinates by any of the known methods, for example, inertial, radio engineering or visual comparing the ground speed with the speed relative to the air and / or comparing the current coordinates with the coordinates obtained by reckoning, and integrating the received difference signals with speed and / or coordinates, in addition, the result of comparing speeds and / or coordinates before integration is changed in the function of the current heading value, and the determination of wind speed itself is carried out directly in the course of maneuvering.

The components of the wind speed vector U _E , U _N , the error of the airspeed sensor ΔV are determined as follows:

where ΔX and ΔY are difference signals in coordinates or velocity.

When using differential signals in coordinates:

ΔX = X _EB -X _E , ΔY = Y _NB -Y _N ,

where X _E and Y _N coordinates of the actual location of the aircraft, measured by any of the known methods, and X _EB and Y _NB are obtained by integrating the components of the airspeed vector in the earth's coordinate system:

V _EB = V _XГ sinΨ + V _ZГ cosΨ + U _E ,

V _NB = V _XГ cosΨ + V _ZГ sinΨ + U _N ,

V _XГ , V _ZГ - components of the airspeed vector in a horizontal airplane coordinate system:

V _XГ = (V _AND -ΔV) (cosϑ + α _АТ sinϑcosγ + β _CK sinϑsinγ),

V _ZГ = (V _AND -ΔV) (β _CK cosγ-α _AT sinγ),

V _And - the longitudinal component of the airspeed vector, measured by the airspeed sensor, α _АТ , _βК - angles of attack and slip, measured by the sensors of the angle of attack and the angle of glide, Ψ, γ, υ - parameters of the angular orientation of the aircraft: course, roll, pitch, measured by inertial course-vertical.

When using differential speed signals:

ΔX = V _EB -W _E , ΔY = V _NB -W _N ,

where W _E and W _{N are the} components of the path velocity vector measured by any of the known methods.

Since, as mentioned above, random errors are present in the measured coordinates of the actual location and ground speed of the aircraft, and the course, roll, pitch, speed, angle of attack and glide angle change due to arbitrary maneuvers of the aircraft, it is advisable to use K _ij to determine the law of regulation of gain one of the known methods of statistical optimal estimation of systems with variable parameters, for example, the Kalman optimal filtering method [4], which is currently widely used for I estimation of random parameters, including uncertainties systems in various fields of technology.

In this case, the gain K _ij will be elements of a time-varying gain matrix K (t) determined by the matrix equations:

K (t) = P (t) H (t) R ^-1 (t),

P (t ₀ ) = P ₀ .

When using difference signals with respect to the coordinates, the matrices H (t) and R (t) have the form:

When using differential signals with respect to speed, the matrices H (t) and R (t) have the form:

The matrix F (t) and the initial value of the matrix P (t) for both versions of the difference signals have the form:

,

,

,

,

,

,

,

,

- дисперсии случайных погрешностей системы по координатам, составляющим скорости ветра, воздушной скорости

- дисперсии случайных погрешностей измерителя координат фактического местоположения ЛА,

- дисперсии случайных погрешностей измерителя путевой скорости ЛА, а коэффициенты матрицы F(t) равны:Where

,

,

,

,

- variance of random system errors in the coordinates of the wind speed, airspeed

- variance of random errors of the coordinate meter of the actual location of the aircraft,

- variance of random errors of the aircraft ground speed meter, and the matrix coefficients F (t) are equal to:

f _1V = sinΨ,

f _2V = cosΨ.

The dependence of the gain K _ij on the current values of the aircraft heading allows you to individually determine the components of the wind speed and the error of the airspeed sensor in the maneuver sections of the heading.

The proposed method for measuring wind speed on board an aircraft compares favorably with the prototype method in that the wind speed is measured in the best way when maneuvering the aircraft along the course with the simultaneous automatic determination of the error of the airspeed sensor, which improves the accuracy of determining the components of wind speed.

The implementation of the prototype method in the form of a device, taking into account only the features essential for the present invention, can be represented in the form of a functional block diagram depicted in figure 1.

The prototype device includes:

- air speed sensor (ICE) - 1;

- angle of attack and slip sensor (DUAS) - 2;

- heading and vertical sensor (DKV) - 3;

- sensor for ground speed and location coordinates (DSC) - 4;

- a unit for determining the components of the relative velocity vector (BOS) - 5;

- four integrators (I1, I2, I3, I4) - 6, 7, 8, 9, respectively;

- six amplifiers (U1, U2, U3, U4, U5, U6) - respectively 10, 11, 12, 13, 14, 15;

- ten adders C1, C2, C3, C4, C5, C6, C7, C8, C9, C10 - 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, respectively.

The disadvantages of the prototype device are similar to the disadvantages of the prototype method above.

The purpose of the invention in the form of an integrated navigation system (SPS) is similar to the purpose of the invention in the form of the method described above.

The goal for the KNS, which implements the method of determining the wind speed on board the aircraft, is achieved by the fact that in the KNS, which includes an airspeed sensor, an adder, a sensor for ground speed and location coordinates, connected by four outputs respectively to the inputs of the fourth, eighth, fifth and ninth adders, sensors of angles of attack and slip, course and vertical, outputs connected to the inputs of the unit for determining the components of the relative velocity vector, two outputs of which, respectively, through series-connected w The second adder, the third adder, the first integrator and the sixth adder, the seventh adder, the second integrator connected in series to the second inputs of the fourth and eighth adders, the second inputs of the second, sixth, fifth and ninth adders connected respectively to the outputs of the third integrator, fourth integrator, second and the sixth adder, a correction signal generating unit has been introduced, with five inputs connected respectively to the outputs of the heading and vertical sensors, of the fourth, fifth, eighth and ninth ummators, and with five outputs connected to the inputs of the third adder, seventh adder, third integrator, fourth integrator and newly introduced fifth integrator, the output of which is fed to the input of the first adder, the second input of which is connected to the output of the airspeed sensor, and the output is fed to the third input of the unit determining the components of the relative velocity vector

The proposed SPS is presented in figure 2 in the form of a functional block diagram and includes:

- airspeed sensor - ICE;

- sensor of angles of attack and slip - DUAS;

- heading and vertical sensor - DKV;

- sensor for ground speed and location coordinates - DSC;

- unit for determining the components of the vector of relative velocity - BFB;

- five integrators - I1, I2, I3, I4, I5;

- nine adders - C1, C2, C3, C4, C5, C6, C7, C8, C9;

- block generating corrective signals - BCS.

The proposed KNS works as follows.

ICE measures the longitudinal component of the aircraft speed vector relative to air - the true air speed V _And . Currently, systems based on the aerometric method have found the most widespread use for measuring true airspeed.

DUAS measures the angles of orientation of the aircraft relative to the airspeed vector: angle of attack α _AT and glide angle β _SK . Currently, systems based on the aerometric method are most widely used for measuring angles of attack and slip.

ICE and DUAS jointly implement the function of measuring the airspeed of the aircraft.

DSC measures the speed of the aircraft relative to the earth's surface - the ground speed W and the coordinates of the actual location X _E and Y _N. Currently, inertial, radio engineering and survey-comparative (visual, along the relief fields) methods are most widely used to measure the components of the ground speed vector and the coordinates of the actual location. In particular, for the simultaneous measurement of ground speed and location coordinates, satellite navigation systems (SNA) are very widely used on board modern aircraft.

DKV measures the parameters of the angular orientation of the aircraft relative to the earth's surface - the course Ψ, roll γ and pitch υ. Currently, systems based on the inertial method are most common for measuring aircraft orientation angles. As such a sensor, an inertial navigation system, an inertial heading vertical, or a combination of specialized heading and vertical sensors can be used.

In adder C1, the error of the internal combustion engine ΔV is taken into account, the estimate of which is made on the I5 integrator:

V = V _AND -ΔV.

In biofeedback, the components of the aircraft airspeed vector are determined in the Earth's coordinate system:

V _E = V [cosϑ + α _AT sinϑcosγ + β _CK sinϑsinγ) sinΨ + (β _CK cosγ-α _AT sinγ) cosΨ],

V _N = V [cosϑ + α _AT sinϑcosγ + β _CK sinϑsinγ) cosΨ + (β _CK cosγ-α _AT sinγ) sinΨ].

In the adders C2 and C6, the components of the wind speed U _E , U _{N are} taken into account, the evaluation of which is made on the integrators I3 and I4:

V _EB = V _E + U _E ,

V _NB = V _N + U _N.

The coordinates X _ЕВ and Y _NB are calculated by integrating the components of the airspeed vector and the correcting signals δ _K1 , δ _K2 from the BCS on the integrators I1 and I2:

where X _E0 and Y _N0 are the initial values of the coordinates X _E and Y _N.

The components of the wind speed vector U _E , U _N and the error of the airspeed sensor ΔV are determined on the integrators I3, I4 and I5 based on the correcting signals δ _K3 , δ _K4 , δ _K5 from BCS as follows:

Corrective signals δ _K1 , δ _K2 , δ _K3 , δ _K4 , δ _K5 in BCS are generated as follows:

δ _K1 = K ₁₁ ΔX + K ₁₂ ΔY,

δK ₂ = K ₂₁ ΔX + K ₂₂ ΔY,

δ _K3 = K ₃₁ ΔX + K ₃₂ ΔY,

δ _K4 = K ₄₁ ΔX + K ₄₂ ΔY,

δ _K5 = K ₅₁ ΔX + K ₅₂ ΔY,

where ΔX and ΔY are difference signals in coordinates or velocity.

When using differential signals in coordinates, the signals ΔX and ΔY are formed on the adders C3 and C4:

ΔX = X _EB -X _E ,

ΔY = Y _NB -Y _N ,

where X _E and Y _N coordinates of the actual location of the aircraft, measured by DSC.

When using the differential signals in speed, the signals ΔX and ΔY are formed on the adders C5 and C9:

ΔX = V _EB -W _E ,

ΔY = V _NB -W _N ,

where W _E and W _{N are the} components of the path velocity vector measured by DSC.

Gains K _ij are formed in BCS and are elements of the time-varying gain matrix K (t), determined by the matrix equations:

K (t) = P (t) H (t) R ^-1 (t),

P (t ₀ ) = P ₀ .

When using difference signals with respect to the coordinates, the matrices H (t) and R (t) have the form:

When using differential signals with respect to speed, the matrices H (t) and R (t) have the form:

The matrix F (t) and the initial value of the matrix P (t) for both versions of the difference signals have the form:

,

,

,

,

- дисперсии случайных погрешностей системы по координатам, составляющим скорости ветра, воздушной скорости

- дисперсии случайных погрешностей измерителя координат фактического местоположения ЛА,

- дисперсии случайных погрешностей измерителя путевой скорости ЛА, а коэффициенты матрицы F(t) равны:Where

,

,

,

,

- variance of random system errors in the coordinates of the wind speed, airspeed

- variance of random errors of the coordinate meter of the actual location of the aircraft,

- variance of random errors of the aircraft ground speed meter, and the matrix coefficients F (t) are equal to:

f _1V = sinΨ,

f _2V = cosΨ.

The formation of gain coefficients K _ij in the BCS, depending on the current values of the aircraft heading, allows individually assessing the components of the wind speed U _E , U _N on the I3 and I4 integrators, and the error of the airspeed sensor ΔV on the I5 integrator.

The proposed SPS compares favorably with the prototype device in that the wind speed is measured in the best way when maneuvering the aircraft at the heading while automatically detecting the error of the airspeed sensor, which improves the accuracy of determining the components of the wind speed, determining the airspeed vector, and calculating the coordinates of the location of the aircraft.

Figure 3 presents the simulation results of the proposed method and SPS graphs of transients for estimating the components of the wind speed vector U _E , U _N and the internal combustion engine error ΔV in the headland at the heading, obtained by modeling on a computer.

It was assumed that a satellite navigation system was used as a speed and actual location meter and the following assumptions were made:

- the components of the wind speed U _X , U _Y are random processes with correlation functions of the form R _UxUx = R _UyUy = σ ² e ^{-β | τ |} where σ ² varies depending on the flight altitude and time of the year within 10 ÷ 25 m / s, and the attenuation coefficient of the correlation function of the wind β = 10 ^-3 ÷ 10 ^-4 sec ^-1 ;

- the ICE error for a certain altitude and flight speed is the sum of a constant value ΔV ₀ and a random function of time such as "white" noise ΔV _C :

ΔV = ΔV ₀ + ΔV _C ;

- the error in measuring the components of the path velocity vector W by the path velocity sensor is fluctuation noise such as white noise, the intensity of which

where σ _Vx = σ _Vy = 0.2 ÷ 0.3 m / s.

через 50 сек после начала коррекции и значениями составляющих скорости ветра U_E=20 м/сек, U_N=15 м/сек и погрешности ДВС ΔV=10 м/сек.Transient graphs are constructed for a simulated flight with a speed of V = 250 m / s, with a turn with an angular velocity

50 seconds after the start of correction and the values of the components of the wind speed U _E = 20 m / s, U _N = 15 m / s and the internal combustion engine error ΔV = 10 m / s.

From the above graphs it follows that one can expect the separation of the components of the wind speed and the internal combustion engine errors with the given accuracy U = ΔV = 2 m / s after 90-120 seconds after the start of the turn.

Using the proposed method and device in aviation equipment will increase the accuracy of solving navigation and other problems and, therefore, increase the efficiency of using aircraft.

The implementation of the proposed method and devices does not imply a change or addition of equipment installed on board the aircraft, involves the use of only known devices and systems from the onboard equipment of the aircraft and therefore the invention can be implemented on the existing technical basis on virtually any type of aircraft.

Claims (2)

1. The method of determining the wind speed on board an aircraft based on measuring the angular orientation and speed relative to air, reckoning the distance traveled relative to air, measuring the ground speed and / or location coordinates using any of the known methods, for example, inertial, radio engineering or visual, comparing the track speed with speed relative to air and / or comparing current coordinates with coordinates obtained by reckoning, and integrating the received differential signals with respect to speed and / or coordinates, characterized in that the result of comparing the speeds and / or coordinates before integration is changed in the function of the current heading value, and the determination of wind speed itself is carried out directly in the course of maneuvering at the heading. 2. An integrated navigation system for implementing the method for determining wind speed on board an aircraft according to claim 1, including an airspeed sensor, an adder, a ground speed sensor and position coordinates, connected by four outputs respectively to the inputs of the fourth, eighth, fifth and ninth adders, sensors angles of attack and slip, course and vertical, outputs connected to the inputs of the unit for determining the components of the relative velocity vector, the two outputs of which, respectively, in series with a single second adder, a third adder, a first integrator and a sixth adder, a seventh adder, a second integrator connected in series to the second inputs of the fourth and eighth adders, the second inputs of the second, sixth, fifth and ninth adders connected respectively to the outputs of the third integrator, fourth integrator, the second and sixth adders, characterized in that the input unit for the formation of corrective signals, five inputs connected respectively to the outputs of the heading sensor and vertical, four of the fifth, eighth and ninth adders, and with five outputs connected to the inputs of the third adder, the seventh adder, the third integrator, the fourth integrator and the newly introduced fifth integrator, the output of which is fed to the input of the first adder, the second input of which is connected to the output of the airspeed sensor, and the output is fed to the third input of the unit for determining the components of the relative velocity vector.

Images