RU2485538C1 - Method to measure roll angle of mobile object and device for its realisation - Google Patents

Abstract

FIELD: radio engineering, communications.

SUBSTANCE: proposed polarisation-modulation method to measure a roll angle of a mobile object and device for its realisation are based on the fact that from two points with available coordinates orthogonally linearly polarised electromagnet waves are radiated with equal amplitudes, phases and lengths of waves, on board of the mobile object a summary electromagnet wave is received, and its polarisation plane is rotated with a certain frequency, according to a phase of spectral component measured at the receiver's outlet at doubled frequency of polarisation rotation plane of received signals, the roll angle of the mobile object is identified.

EFFECT: elimination of permanent accumulation of a measurement error with course of time, expansion of functional capabilities of radio-navigation systems that measure bearing of a mobile object with a polarisation-modulation method.

2 cl, 1 dwg

Description

The invention relates to radio navigation and can be used, for example, in flight navigation systems for aircraft orientation (LA) when it approaches the instrument.

Known methods and devices for measuring the roll angle of a moving object are based on the use of inertial navigation systems, in particular gyroscopic orientation systems [1-4]. With regard to aircraft, such inertial navigation systems have a number of disadvantages. First, over time, there is a constant accumulation of measurement errors and for one hour of flight it is a unit of degrees [2, 3]. Secondly, if the aircraft develops significant overloads, then there is an increase in the gyroscope’s own precession rate, which in some cases can lead to a complete loss of its operability [2].

Since the known inertial means of measuring the roll angle of a moving object are based on a different physical principle, compared with the claimed one, they cannot be considered as analogues, since they do not have common features.

A known method of measuring the bearing of a moving object and a device for its implementation (USSR patent No. 1251003, Mcl 4 G01S, 3/02, priority from 01/29/85) [5].

A method of measuring the bearing of a moving object is that from two points with known coordinates located in the measurement plane at a distance d from each other, orthogonally polarized electromagnetic waves with equal amplitudes, phases and wavelengths are emitted. Orthogonally polarized electromagnetic waves are received at a moving object and the phase difference Δφ between them is measured. After that, the bearing β of the moving object is determined relative to the normal to the middle of the line connecting the emission points of electromagnetic waves, according to the formula:

where λ is the wavelength of the radiated orthogonally polarized electromagnetic waves.

The disadvantage of this method is its limited functionality, which consists in measuring only one navigation element - bearing of a moving object and does not measure its roll angle.

A device for measuring the bearing of a moving object contains a transmitter with two transmitting antennas connected to it with orthogonal linear polarizations, located at points with known coordinates in the measurement plane at a distance d from each other and located on the moving object, a receiving all-polarized antenna, a linear polarizing separator, amplitude phase discriminator and calculator. The input of the linear polarizing separator is connected to the output of the receiving all-polarized antenna, its two outputs are connected to two inputs of the amplitude-phase discriminator, and its output is connected to the input of the computer. Moreover, the linear polarizing separator is oriented so that its unit coordinates of the coordinate system coincide with the axes of the shoulders of the rectangular waveguides and make an angle of 45 ° with the measurement plane. The operation of the device lies in the fact that the transmitter emits orthogonally linearly polarized electromagnetic waves through two transmitting antennas connected to it. On a moving object, the total electromagnetic wave is received by an all-polarized antenna and is fed to a linear polarizing separator, where the incoming, at the input of the total electromagnetic wave, is divided into two linear electromagnetic waves orthogonal in polarization. In the amplitude-phase discriminator, the amplitudes of the orthogonally linearly polarized signals are measured, their ratio is formed and the phase difference Δφ is measured, in accordance with (1) the bearing of the moving object is calculated.

The disadvantage of this device is the limited functionality due to the fact that only the bearing of a moving object is measured and it is not possible to measure its roll angle.

A known navigation system for measuring the bearing of a moving object (A.S. No. 1355955, M.cl. 4 G01S, 3/02, priority from 9.12.85) [6], which eliminates the influence of the angle of heel of a moving object on the accuracy of measuring its bearing . This navigation system contains a transmitter with two transmitting antennas connected to it with orthogonal linear polarizations located at points with known coordinates in the measurement plane at a distance d from each other. Moreover, emitted orthogonally linearly polarized electromagnetic waves have equal amplitudes, phases and wavelengths. On a moving object, the navigation system contains an all-polarized receiving antenna, a round waveguide section with an integrated quarter-wave phase plate, the input of which is connected to the output of the all-polarized receiving antenna, a linear polarizing separator, the input of which is connected to the output of the circular waveguide section with an integrated quarter-wave phase plate, two amplitude discriminator, two the input of which is connected to two outputs of the linear polarizing separator and the computer, the input of which is connected to the output do amplitude discriminator. Moreover, the quarter-wave phase plate is oriented at an angle of 45 ° to one of the walls of a rectangular waveguide of a linear polarizing separator.

The peculiarity of the operation of this navigation system is that the combination of a circular waveguide section with an integrated quarter-wave phase plate with a linear polarizing separator allows the reception of orthogonally linearly polarized electromagnetic waves in a circular polarizing base on a moving object. Therefore, the ratio of amplitudes of orthogonally polarized signals generated at the output of the amplitude discriminator is determined only by the phase difference Δφ between the emitted electromagnetic waves and does not depend on the angle of heel of the moving object.

The disadvantage of this navigation system is the limited functionality, namely, that only the bearing of a moving object is measured and its roll angle is not measured.

The closest set of features to the claimed method of measuring the angle of heel of a moving object and a device for its implementation is a radio navigation system for determining the direction, which implements a polarization-modulation method of measurement (AS No. 1438449, M.cl. 4 G01S, 3/02, priority from 03.25.87) [7].

The essence of the polarization-modulation method for measuring the bearing of a moving object is that from two points with known coordinates located in the measurement plane at a distance d from each other, orthogonally linearly polarized electromagnetic waves with equal amplitudes, phases and wavelengths are emitted. On board the moving object, the total electromagnetic wave is received by the all-polarized receiving antenna and its polarization plane is rotated with a frequency of Ω. Then, in a linear orthogonal polarization basis, a linearly polarized component is extracted from the received total electromagnetic wave. As a result of rotation of the plane of polarization, the received signal at the output of the receiver becomes amplitude modulated by twice the rotation frequency of the plane of polarization 2Ω. Then, the spectral component at a frequency of 2Ω is extracted from the received signal, its amplitude is measured, and the phase difference Δφ between the orthogonally linearly polarized electromagnetic waves is determined from the measured amplitude, after which the bearing of the moving object β is calculated by the formula (1).

The disadvantage of this method is the limited functionality, consisting in the fact that only one navigation element is measured - the bearing of a moving object and its roll angle is not measured.

The radionavigation system for measuring the bearing of a moving object contains a transmitter with two transmitting antennas connected to it with their own orthogonal linear polarizations and located at points with known coordinates in the measurement plane at a distance d from each other and a receiving all-polarized antenna located on a moving object, a polarization plane rotator, master oscillator, polarizer, logarithmic receiver, band-pass filter, amplitude detector and indicator, while the output of the receiver The second all-polarized antenna is connected to the signal input of the rotator of the polarization plane, and its control input is connected to the output of the master oscillator, the output of the rotator of the polarization plane is connected to the input of the polarizer from the side of the circular waveguide, and its output from the side of the rectangular waveguide is connected to a series-connected logarithmic receiver, a bandpass filter amplitude detector and indicator.

The operation of the radio navigation system is as follows.

The transmitter, through two transmitting antennas connected to it with orthogonal intrinsic linear polarizations, emits orthogonally, linearly polarized electromagnetic waves with equal amplitudes, phases and wavelengths. On a moving object, the total electromagnetic wave is received by the all-polarized receiving antenna and fed to the input of the rotator of the plane of polarization. The frequency of rotation of the plane of polarization is equal to Ω and is set by the frequency of the master oscillator. From the output of the rotator of the plane of polarization, the total electromagnetic wave is fed to the input of the polarizer, which is a transition from a circular to rectangular waveguide, where its linearly polarized component is extracted. Due to the rotation of the plane of polarization at the output of the logarithmic receiver, a signal is generated that is modulated in amplitude by twice the speed of rotation of the plane of polarization 2Ω. At the same time, the depth of submission is determined by the phase difference Δφ between the orthogonally linearly polarized electromagnetic waves emitted by the transmitting antennas. The band-pass filter extracts a spectral component from the received signal at a frequency of 2Ω, after which it is detected in the amplitude detector. From the output of the amplitude detector, the signal goes to an indicator whose scale is calibrated in degrees of the bearing of a moving object.

The disadvantages of this radio navigation system include limited functionality, which is manifested in the fact that only one navigation element is measured - the bearing of a moving object and its roll angle is not measured.

The method of measuring the roll angle of a moving object is that from two points with known coordinates located in the measurement plane at a distance d from each other, orthogonally linearly polarized electromagnetic waves with equal amplitudes, phases and wavelengths are emitted, the total electromagnetic the wave of the all-polarized receiving antenna and carry out the rotation of the plane of polarization of the total electromagnetic wave with a frequency Ω, emit in a linear orthogonal polarization nnom basis of the received total electromagnetic wave linearly polarized component, and then from the received signal is isolated spectral component at twice the frequency of rotation of plane 2Ω polarization differs from the prototype in that from the received total electromagnetic wave isolated horizontally linearly polarized component and the measured phase φ _2Ω spectral component at doubled frequency of rotation of the plane of polarization 2Ω relative to twice the angular position of the plane of polarization of the received total of the electromagnetic wave, while the emission points are located in a horizontal plane, the emitted electromagnetic waves have horizontal and vertical orientations of the plane of polarization, coinciding with the horizontal plane and perpendicular to this plane, respectively, and the unit vectors of the linear orthogonal polarizing base in which the electromagnetic waves are received coincide with the transverse and vertical axes of the moving object and together with its longitudinal axis form in space associated with orpusom movable object, a normal rectangular coordinate system and determining the roll angle γ of the mobile object between its transverse axis and the horizontal plane.

We establish the relationship between the spectral characteristics of the received signal and the angle of heel of the moving object γ, using the well-known formalism of vectors and Jones matrices [8].

Then the total electromagnetic wave received at the moving object by the all-polarized receiving antenna can be represented in vector form taking into account (1) in the form:

- вектор Джонса горизонтально линейно поляризованной излучаемой электромагнитной волны, представленный в линейном ортогональном поляризационном базисе,Where

- the Jones vector of a horizontally linearly polarized radiated electromagnetic wave, presented in a linear orthogonal polarizing basis,

- вектор Джонса вертикально линейно поляризованной излучаемой электромагнитной волны, представленный в линейном ортогональном поляризационном базисе,

- the Jones vector of a vertically linearly polarized radiated electromagnetic wave, presented in a linear orthogonal polarization basis,

- фазовый сдвиг между излучаемыми ортогонально линейно поляризованными электромагнитными волнами в направлении β,

- phase shift between radiated orthogonally linearly polarized electromagnetic waves in the direction β,

- вектор Джонса суммарной электромагнитной волны, представленный в собственном линейном ортогональном поляризационном базисе, единичные орты которого совпадают с горизонтальной плоскостью и перпендикуляром к этой плоскости соответственно.

- Jones vector of the total electromagnetic wave, represented in its own linear orthogonal polarization basis, the unit vectors of which coincide with the horizontal plane and the perpendicular to this plane, respectively.

The received signal at the input of the receiver can be represented in its own linear orthogonal polarization basis, the unit vectors of which coincide respectively with the transverse and vertical axes of the moving object, taking into account (2), in the form:

Where

- матрица Джонса оператора поворота по часовой стрелке относительно горизонтали на угол крена +γ,

- the Jones matrix of the rotation operator clockwise relative to the horizontal angle of heel + γ,

- матрица Джонса оператора поворота по часовой стрелке относительно горизонтали на угол крена -γ,

- the Jones matrix of the rotation operator clockwise relative to the horizontal angle of angle -γ,

- матрица Джонса вращателя плоскости поляризации на угол α=Ωt(Ω - частота вращения),

- the Jones matrix of the rotator of the plane of polarization at an angle α = Ωt (Ω is the rotation frequency),

- оператор поляризатора (переход с круглого волновода на прямоугольный), с горизонтальной собственной поляризацией.

- polarizer operator (transition from a circular to a rectangular waveguide), with horizontal intrinsic polarization.

Having done the necessary matrix transformations in (3), we obtain:

The amplitude of the signal at the output of the receiver having a logarithmic amplitude characteristic and a linear detector, taking into account the equality α = Ωt, will be equal to:

From analysis (5), we see that in the envelope spectrum of the output signal of the logarithmic receiver, there is only the spectral component at the doubled rotation frequency of the polarization plane 2Ω. Moreover, the amplitude of this component is determined by the phase difference Δφ between the emitted orthogonally linearly polarized electromagnetic waves, which is fully consistent with the prototype [7]. At the same time, the phase of this spectral component φ _{2Ω, the} frequency 2Ω is determined only by the roll angle γ of the moving object and, in accordance with (5), are interconnected by the relation:

where φ _2Ω is the phase of the spectral component at a frequency of 2Ω (in radians),

+ γ - corresponds to a positive roll angle when the transverse axis of the moving object (or its right wing in the case of an aircraft) is below the horizontal plane,

-γ - corresponds to a negative roll angle when the transverse axis of the moving object (or its right wing in the case of an aircraft) is above the horizontal plane.

The use of the claimed combination of features for measuring the roll angle of a moving object in known solutions by the author was not found.

Figure 1 presents the structural electrical diagram of a device that implements the proposed method for measuring the roll angle of a moving object.

The device contains a transmitter 1, transmitting antennas 2 and 3, located at points with known coordinates and spaced apart in a horizontal plane at a distance d from each other, on board a moving object, the device contains a receiving all-polarized antenna 4, a polarization plane rotator 5, a polarizer 6, a master oscillator 7, a logarithmic receiver 8, a reference driver 9, a bandpass filter 10, a phase detector 11, and an indicator 12.

The device operates as follows.

The transmitter 1, through two transmitting antennas 2 and 3 connected to it with orthogonal proper linear polarizations, emits in the direction of the moving object, orthogonally linearly polarized electromagnetic waves, respectively, with horizontal and vertical orientation of the polarization plane with equal amplitudes, phases and wavelengths.

On a moving object, the total electromagnetic wave, whose Jones vector in the β direction has the form (2), is received by the all-polarized receive antenna 4. From the output of the all-polarized receive antenna 4, the signal is fed to the input of the polarization plane rotator 5. The frequency of rotation of the polarization plane is Ω and is set by the frequency of the reference generator 7. From the output of the rotator of the plane of polarization 5, the signal is fed to the input of the polarizer 6 from the side of the circular waveguide, where horizontally linearly polarized components are extracted signal. The output signal of the polarizer 6 from the side of the rectangular waveguide, presented in the form of (4), is fed to the input of the logarithmic receiver 8.

As a result of rotation of the plane of polarization at the output of the logarithmic receiver 8, a signal is generated, presented in the form (5), modulated in amplitude by twice the frequency of rotation of the plane of polarization 2Ω. In this case, the modulation depth is determined by the phase difference Δφ between the orthogonally linearly polarized electromagnetic waves emitted by the transmitting antennas 2 and 3. The bandpass filter 10 will isolate the spectral component at a frequency of 2Ω, after which the selected signal is fed to one of the inputs of the phase detector 11. At the same time, the output of the master oscillator 7, a signal with a frequency Ω is fed to the input of the driver of the reference signal 9, where a reference signal is generated with a double frequency of 2Ω, which is fed to the other input of the phase detector 11. V phase detector 11 measures the phase φ _{2Ω of the} spectral component at twice the rotation frequency of the polarization plane 2Ω relative to the doubled angular position of the polarization plane of the received total electromagnetic wave, presented in the form (2). From the output of the phase detector 11, the signal enters the indicator 12, the scale of which can be calibrated, taking into account (6), in degrees of the angle of heel of the moving object γ.

In the 3 cm wavelength range of the inventive device for measuring the roll angle of a moving object can be performed as follows.

As a transmitter, for example, a standard high-frequency signal generator of the G4-83 type can be used, the output of which is connected to a power divider made in the form of a double waveguide T-shaped splitter (see [9], p.401). Moreover, the first output of the splitter is connected to the transmitting antenna 2, and its second output is connected through a segment of a rectangular waveguide twisted by 90 ° to the transmitting antenna 3.

As the transmitting antennas 2 and 3, a horn antenna can be used ([10], p.248) and, taking into account the peculiarities of their connection to the transmitter, electromagnetic waves with vertical and horizontal polarization planes will be emitted, respectively.

The receiving all-polarized antenna 4 can be made in the form of a round horn (see [11], p.510).

The rotator of the plane of polarization 5 can be made in the form of a Faraday rotator of the plane of polarization (see [12], p. 344).

Polarizer 6 can be made in the form of a transition from a circular to rectangular waveguide (see [12], p. 438).

The master oscillator 7 can be made in the form of a standard low-frequency signal generator type G3-102.

The logarithmic receiver 8 coincides with a similar receiver of the known amplitude-amplitude monopulse system (see [13], p.20).

The driver of the reference signal 9, a band-pass filter 10, a phase detector 11 can be performed using well-known technical solutions [14].

The indicator 12 can be made, for example, in the form of a voltmeter of direct current type B2-11, the scale of which is calibrated in degrees of the angle of heel of a moving object.

The inventive method and device for measuring the angle of heel of a moving object allows you to expand the functionality of the radio navigation system for determining the bearing of a moving object by measuring an additional navigation element - the angle of heel of a moving object. In addition, compared with the widely used means of measuring the angle of heel of a moving object, based on the use of gyroscopic orientation systems, the inventive method and device for measuring the angle of heel of a moving object can avoid the constant accumulation of measurement errors over time.

Sources of information used in the preparation of the description of the invention:

1. A.S. Aleksandrov, G.R.Arno and others. The current state and development trends of foreign means and navigation systems of moving objects of military and civil purposes. - St. Petersburg, 1994 .-- 119 p.

2. D.S. Pelpor, V.V. Yagodkin. Gyroscopic systems. - M., Higher School, 1977 .-- 216 p.

3. Agadzhapov P.A., Vorobev V.G. et al. Automation of aircraft navigation and air traffic control. - M.: Transport, 1980 .-- 357 p.

4. Yarlykov M.S. Statistical theory of radio navigation. - M .: Radio and communications, 1985 .-- 344 p.

5. Badulin NN, Gulko V.L. A method for measuring the bearing of a moving object and a device for the share of its implementation. - USSR patent No. 1251003, M.cl. 4 G01S, 3/02, priority from 01.29.85.

6. Badulin NN, Gulko V.L. Navigation system for bearing detection. - A.S. USSR No. 1355955, M.cl. 4 G01S, 3/02, priority from 9/12/85.

7. Badulin N.N., Gulko V.L., Petrov A.F. Radio navigation system for determining the direction. - A.S. USSR No. 1438449, M.cl. 4 G01S, 3/02, priority from 03.25.87.

8. Azzam R., Bashar P. Ellipsometry and polarized light. - M .: Mir, 1981. - 588 p.

9. Zhuk M.S., Molochkov Yu.B. Design of lens scanning wide-range antennas and feeder devices. - M .: Energy, 1973.

10. Dryabkin A.L. and other Antenna-feeder devices. - M .: "Soviet Radio", 1974.

11. Zhuk M.S., Molochkov Yu.B. Design of antenna-feeder devices. - M .: "Energy", 1966.

12. Kanareikin D.B., Pavlov N.F., Potekhin V.A. Polarization of radar signals. - M .: "Soviet Radio", 1966.

13. Leonov A.I., Fomichev K.I. Monopulse radar. - M .: Soviet Radio, 1970.

14. Aleksenko A.G. Fundamentals of microcircuitry. - M .: Soviet Radio, 1977.

Claims (2)

1. The method of measuring the roll angle of a moving object, which consists in the fact that from two points with known coordinates located in the measurement plane at a distance d from each other, orthogonally polarized electromagnetic waves with equal amplitudes, phases and wavelengths are emitted on the moving object receive the total electromagnetic wave, characterized in that they rotate the plane of polarization of the received total electromagnetic wave with a frequency Q, select in a linear orthogonal polarization basis from net total electromagnetic wave horizontally linearly polarized component, determine the output amplitude of the signal
E _o (t) = log1 / 2 · [1 + cosΔφ · sin (2Ωt ± 2γ)],
where Δφ is the phase difference between the radiated orthogonally linearly polarized electromagnetic waves at the receiving point,
isolate the spectral component at twice the rotation frequency of the polarization plane 2Ω, measure its phase φ _2Ω relative to the doubled angular position of the polarization plane of the received total electromagnetic wave, which is determined by the angle of heel γ of the moving object, and determine the angle of heel γ of the moving object between the transverse axis of the moving object and the horizontal plane according to the formula:

where φ _2Ω is the phase of the spectral component at a frequency of 2Ω (in radians),
+ γ is the positive angle of the roll of the moving object, when the right, in the direction of travel, the transverse axis is below the horizontal plane,
-γ is the negative roll angle of the moving object when its right, in the direction of travel, transverse axis is above the horizontal plane, while the emission points of electromagnetic waves are in the horizontal plane, the emitted electromagnetic waves have linear horizontal and vertical orientations of the polarization plane, corresponding respectively horizontal plane and perpendicular to this plane, and unit vectors of the linear orthogonal polarization basis, in which the total electron omagnitnaya wave coincide with the transverse and vertical axes of the movable object, respectively. 2. A device for measuring the roll angle of a moving object, comprising a transmitter with two transmitting antennas with orthogonal polarizations connected to it, located at points with known coordinates in the measurement plane at a distance d from each other, and a receiving all-polarized antenna located on the moving object, characterized the fact that a polarization plane rotator is introduced, made in the form of a Faraday polarization plane rotator based on a circular waveguide, a master oscillator tuned to the rotation of the polarization plane, the driver of the reference signal tuned to double the frequency of rotation of the plane of polarization, the polarizer made in the form of a transition from a circular waveguide to a rectangular, logarithmic receiver, a band-pass filter tuned to double the frequency of rotation of the plane of polarization, a phase detector and an indicator, the signal input of the Faraday rotator of the plane of polarization is connected to the output of the all-polarized receiving antenna, and its control input is connected to the output of the master generator, the input of the reference signal driver is connected to the output of the master oscillator, the input of the polarizer from the side of the circular waveguide is connected to the output of the Faraday rotator of the plane of polarization, and the output of the polarizer from the side of the rectangular waveguide is connected to the input of the logarithmic receiver, and its output is connected to the input of the bandpass filter, the first input the phase detector is connected to the output of the reference signal driver, and its second input is connected to the output of the bandpass filter, the output of the phase detector is connected to the input indicator, the scale of which is calibrated in degrees of the roll angle of the moving object, while the polarizer’s own polarization is horizontal and coincides with the transverse axis of the moving object, and the transmitting antennas have horizontal and vertical proper polarizations and are located in the horizontal plane.

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