RU2559820C1 - Method for navigation of moving objects - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: method includes using a reference map of an area as a priori information about a navigation field; selecting a portion of the area (measurement portion) located within the reference map; forming a current map by calculating plane coordinates of the measurement portion based on range measurements using a multibeam measurement mode using radio waves, located in two orthogonal planes and emitted in the form of beams, from which the centre beam is emitted first, followed by the left- and right-side beams, wherein the centre beam is perpendicular to the direction of movement of the moving objects, the beam planes are turned about the centre beam by an angle of 45 degrees relative to the direction of movement of the moving objects. Further, the method includes determining the difference of the results of multibeam measurement of inclined ranges; determining the angles of evolution of moving objects on the azimuth, roll and pitch over time based on analysis of Doppler frequency values arising from measurement of ranges on each beam. The value and sign of the azimuth, roll and pitch angles during each range measurement cycle are determined by changing the position of the measured array of Doppler frequencies relative to the array of Doppler frequencies corresponding to zero values of the azimuth, roll and pitch angles. Further, the method includes calculating the altitude of the moving objects in coordinates of the measurement portion at the point of determining the location of the moving objects in plane coordinates of the measurement portion; comparing values of plane coordinates of the current and reference maps; calculating terms of the proximity characteristic for all possible positions of the moving object; searching for the extremum of the proximity characteristic; calculating a motion trajectory correction signal; controlling movement of the moving objects by correcting their location based on three coordinates of the reference map (plane coordinates and altitude) in coordinates of the measurement portion during movement of the moving objects over the measurement portion.

EFFECT: high accuracy of navigation.

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Description

The invention relates to the field of navigation of moving objects and can be used in the construction of various location systems designed to determine the location of moving objects, control their movement and provide navigation for moving objects.

A known method of navigation of moving objects (TO) [1]. The navigation method [1] is as follows.

Use the information of the reference terrain map installed on the BS before the start of the movement about the navigation field of the earth.

Select the necessary area of the terrain of the reference map, which is a measured area and is determined by the value of the permissible deviations of the location of BEFORE the given (square of uncertainty).

A current map is compiled by measuring the parameters of the measuring section using three rays of radio waves located in the same plane, which is perpendicular to the direction of motion of the DO.

The rays of radio waves cyclically emit as follows. The first to emit a beam whose propagation direction is located in a plane orthogonal to the horizon plane of the measured section or in a plane that is at an angle to the horizontal plane of the measured section (first beam). Then, rays are emitted whose propagation directions do not coincide with the propagation direction of the first ray, and the propagation directions of one part of the rays are to the left (in the direction of motion of the DO) of the first ray, and the other part to the right (in the direction of motion of DO) of the first ray.

The parameters of the measured area (height to the surface of the measured area at the points of intersection of the rays with the surface of the measured area at the measurement points) are calculated based on the measurement of ranges using radio waves from the DO to the surface of the measured area.

Calculations are performed similar to those described above, using a reference map for each possible position of DO within the uncertainty square for each hypothesis.

For all hypotheses inside the square of uncertainty, the terms of the proximity indicator are calculated.

At the end of all measurements, an extremum of the proximity indicator is searched.

Corrections to the coordinates of the DO location in the planned coordinates of the measured area are determined based on the analysis of the mutual displacements of the reference and current terrain maps of the measured area (offset of the extremum of the proximity indicator from the center of the uncertainty square).

The height of the DO above the surface of the measured area is calculated in the coordinates of the measured area (at the point of determining the location of the DO in the planned coordinates of the measured area).

Corrections are given to the coordinates of the location of the aircraft in the planned coordinates of the measuring area in three coordinates.

Control the movement of the aircraft by correcting their location in three coordinates as you progress through the measuring section.

The disadvantage of this method [1] is the lack of information about the angles of evolution of a moving object. The fact is that during movement the position of DO in space is dynamic: the azimuth, roll and pitch angles constantly arise and act on the measurement conditions [2]. However, the azimuth, roll and pitch angles of DOs are not taken into account at the time of measurements, which reduces the accuracy of navigation of DOs.

A known method of navigation of moving objects (TO) [3], selected for the prototype. The navigation method [3] is as follows.

Use the information of the reference terrain map installed on the BS before the start of the movement about the navigation field of the earth.

Select the required area of the terrain of the reference map, which is a measured area.

Make up the current map by measuring the parameters of the measured area using three rays of radio waves. Rays of radio waves emit cyclically: first, the first is the central ray (in the direction of motion of the DO), the second is the left ray and the third is the right ray relative to the central ray. The rays of the radio waves are in the same plane (the plane of the rays), perpendicular to the direction of motion of the DO.

In compiling the current terrain map, data on the measured range values using radio wave beams are used, as well as the values of the velocity and angles of evolution of the DO (pitch, roll and course - a priori known data received from another measurement system (inertial navigation system - ANN) before the indicated below measurements). In this case, the pitch angle data have their own measurement error.

Measure the ranges and integrated parameters (PI) of the reflected signals (measured signals) for each beam.

The differences of measurements of the left and central rays, the right and central rays of the current measurement are determined, and the differences of measurements of the central beam in the current measurement and in the previous one are also calculated.

The parameters of the measured area (height to the surface of the measured area at the measurement points) are calculated on the basis of range measurements using radio waves from the DO to the surface of the measured area.

Calculations are performed similar to those described above, using a reference map for each possible position of DO within the uncertainty square for each hypothesis.

For all hypotheses inside the square of uncertainty, the terms of the proximity indicator are calculated.

At the end of all measurements, an extremum of the proximity indicator is searched.

Corrections to the coordinates of the DO location in the planned coordinates of the measured area are determined based on the analysis of the mutual displacements of the reference and current terrain maps of the measured area (offset of the extremum of the proximity indicator from the center of the uncertainty square).

The height of the DO above the surface of the measured area is calculated in the coordinates of the measured area (at the point of determining the location of the DO in the planned coordinates of the measured area).

To eliminate the measurement error due to pitch oscillations in pitch, the integrated parameters (PI) of the measured reflected signals are measured and stored for all three beams during the last measurement of inclined ranges.

On the reference map, the average angle of inclination of the surface and the type of underlying surface for each of the rays during the last measurement are determined from the previously determined measurement points in the local coordinate system during the last range measurement.

A database of the IP of the reference reflected signals for three beams is used, taking into account the deviation of the beam from the vertical and the average angle of inclination of the surface, as well as the type of underlying surface for each beam.

The value of the additional angle of deviation from the vertical by the pitch of each of the rays is determined due to the error in measuring the angular oscillations of the DO by pitch, using the IP of the reference and measured reflected signals for each beam.

Corrections are made to the coordinates of DOs according to the planned coordinates and height based on the determination of the additional angle of deviation from the vertical by the pitch of each beam.

Corrections are given to the coordinates of the DO location in the planned coordinates of the measuring section along three coordinates.

They control the motion of the DO by correcting its location in three coordinates (planned and height) as the measured section passes.

The disadvantage of the method [3] is the low accuracy of determining the additional angle of deviation from the vertical by pitch, since the data on the IP of the reference reflected signals for three rays, taking into account the deviation of the beam from the vertical, the average angle of inclination of the surface and the type of underlying surface for each beam do not take into account the specific terrain on a measured site. In addition, the lack of information about other angles of evolution of a moving object, except pitch, further reduces the accuracy of navigation DO.

The technical result of the invention is to increase the accuracy of navigation by determining the angles of evolution of a moving object - azimuth, roll and pitch during each cycle of range measurements when moving DO above the measured area by measuring the Doppler frequencies that arise when measuring the slant range.

The technical result is achieved by the fact that in the method of navigation of moving objects, which consists in using the reference terrain map as a priori information about the navigation field, selecting a terrain (measured portion) within the reference map, compiling the current map by calculating the planned coordinates of the measured portion based on range measurements using the multi-beam measurement mode using radio waves cyclically emitted in the form of rays, of which the central one is emitted first, and then the left and others lateral with respect to the central one, determining the difference in the results of multipath measurements, determining the angular oscillations of moving objects by the pitch, comparing the values of the planned coordinates of the current and reference maps, calculating the location of moving objects by the three coordinates of the reference map (planned coordinates and height), calculating the signal for correcting the motion path and controlling the movement of moving objects by correcting their location in three coordinates of the reference map (planned coordinates and height) over time The names of the movement of moving objects over the measured area when compiling the current map based on range measurements using the multi-beam measurement mode, the radio waves are located in two orthogonal planes, each of which is rotated around the central beam by an angle equal to 45 degrees relative to the longitudinal axis of the moving objects, and the central the beam is perpendicular to the longitudinal axis of moving objects. The rays of the radio waves are grouped so that the first central beam belongs to one orthogonal plane, the left side rays are located in front of the central beam, and the right side rays are located behind the central beam, and the first central beam belongs to the other orthogonal plane, the left side rays located at the back the central beam, and the right side rays, located in front of the central beam in the direction of movement of moving objects. Side rays belonging to one plane are pairwise symmetrical with respect to the central ray. The calculation of the correction signal of the trajectory of moving objects is carried out taking into account, in addition to the pitch angle, azimuth and roll angles. Evolution angles — azimuth, roll, and pitch — are determined in dynamics based on an analysis of the values of Doppler frequencies arising from the measurements of ranges for each ray. To analyze the values of Doppler frequencies, an array of values of Doppler frequencies is used, obtained from measurements of the Doppler frequencies of the left and right side rays for each orthogonal plane for each cycle of the multipath measurement mode. The value and sign of the angles of azimuth, roll and pitch for each range measurement is determined by comparing the measured array of Doppler frequencies with an array of Doppler frequencies corresponding to zero values of the azimuth, roll and pitch angles for each of the lateral rays of the orthogonal planes, respectively.

The navigation method TO explain the following drawings:

- figure 1 shows two orthogonal planes A and B; in the plane A there are rays: central, first left and first right; in the plane B there are rays: central, second left and second right; the position of the planes A and B relative to the direction of movement is indicated;

- figure 2 defines the angles of azimuth, roll and pitch;

- скорость начала О связанной системы координат ДО;- figure 3 shows the associated coordinate system of a moving object according to GOST 20058-80 [3], OX is the longitudinal axis of the associated coordinate system DO, OY is the normal axis of the associated coordinate system DO, speed $$\overrightarrow{{\displaystyle V}}$$

- the speed of the beginning About the associated coordinate system DO;

- figure 4 shows an array of values of Doppler frequencies F _D (black triangles, designated as 1-4) on the underlying surface in the planned coordinates of the measured area when the pitch angle α _T > 0 for zero roll angles and azimuth α _K = α _A = 0, black dots - the value of the Doppler frequency in the absence of evolution angles;

- figure 5 shows an array of values of Doppler frequencies F _D (black triangles, designated as 1-4) on the underlying surface in the planned coordinates of the measured area when the roll angle α _K > 0 for zero pitch and azimuth angles α _T = α _A = 0, black dots - the value of the Doppler frequency in the absence of evolution angles;

- figure 6 shows an array of values of Doppler frequencies F _D (black triangles, designated as 1-4) on the underlying surface in the planned coordinates of the measured section under the action of the azimuth angle α _A > 0 for zero values of the angle of heel and pitch α _K = α _T = 0, black dots - the value of the Doppler frequency in the absence of evolution angles.

The navigation method is implemented as follows.

The implementation of the navigation method BEFORE we consider the example of compiling the current map using multipath measurements using five rays of radio waves that are located in planes A and B (three in each plane) (Fig. 1).

We will use the correlation-extreme method of navigation (KESN), based on a comparison of current terrain maps with reference maps of the same terrain, which is based on determining the location of DOs and then controlling the movement of DOs by correcting their location. Reference cards are installed on the DO until the start of movement over a given surface of the area, and the current cards are received during the movement of DO. The deviation of the reference terrain maps from the current ones at the given point of the trajectory of movement before determines the deviation of the actual trajectory from the given one, by which a signal for correcting the trajectory of movement is generated and the movement of moving objects is controlled by correcting their location.

Comparison of the reference and current cards is carried out on the basis of the calculation of the functionals that reach the global extremum with full combination of images of these cards. To process the information obtained during the DL movement, difference algorithms are used, based on the calculation of the differences of the measured slope ranges of the current map.

During the movement over the measured area, the current map of the area is determined, for compiling which data on the measured values of the range using the rays of radio waves, as well as the values of the speed and angles of evolution of DOs (pitch, roll and azimuth) are used - a priori known data obtained by other means (inertial DO system) before taking the measurements below.

The initial data for calculations in KESN are:

- a reference map, which is an array of data on the terrain;

- a database of the dependence of the values and signs of the angles of azimuth, roll and pitch on the change in the array of values of the measured Doppler frequencies compared to the array of values of Doppler frequencies at zero values of the angles of azimuth, roll and pitch (array of values of the reference Doppler frequencies);

- the current map, which is an array of measured distances for all beams obtained in each measurement for two orthogonal planes.

Rays of radio waves emit cyclically. In each cycle, the rays of radio waves emit sequentially in the following order. The central ray belongs to two planes: A and B. First, the rays of plane A emit: the first is the central ray located perpendicular to the direction of motion of the DO (Fig. 1), the second is the first left ray located left ahead in front of the central direction of motion of the DO, the third - the first right ray, located on the right behind from the center in the direction of motion DO. Then the rays of plane B are emitted: the fourth is the second left ray located to the left rear relative to the central direction of motion of the DO, the fifth is the second right ray located to the right in front of the central direction of motion of the DO (Fig. 1). The angle between the left rays and the central beam is equal to the angles between the right rays and the central beam. The planes A and B are rotated around the central beam by an angle equal to 45 degrees relative to the longitudinal axis of moving objects and are orthogonal to each other.

Cyclically measure the distance to the terrain for each of the five rays (Fig. 1).

Cyclically measure the Doppler frequencies F _D that arise when measuring distances in the lateral rays: the first and second left rays and the first and second right rays. The Doppler frequencies for a given measurement cycle comprise an array of frequencies, which is determined by four values: the values of the Doppler frequencies of the reflected signals along the left (first and second) and right (first and second) rays, respectively — four black dots in FIG. 4-6.

The differences in the measurements of the ranges of the first left and central rays, the first right and central rays, the second left and central rays, the second right and central rays of the current measurement cycle are determined, and the differences in the measurements of the central beam in the current cycle and in the previous one are also calculated.

When the DO moves, the angles of evolution act: the angles of roll α _K , pitch α _T and azimuth α _A (Fig. 2).

The value and sign of the azimuth, roll and pitch angles are determined for each range measurement cycle by comparing the array of measured Doppler frequencies with the array of reference Doppler frequencies.

Based on the obtained data on the ranges, as well as on the angles of evolution of the DO, the coordinates of the measurement points in the coordinate system associated with the DO are calculated (Fig. 3).

The local coordinates of the projection of the point of the trajectory DO on the plane of the planned coordinates in the coordinates of the measured area are calculated.

The parameters of the measuring section (height to the surface of the measuring section at the measurement points) are calculated based on the difference in the measurements of the distances from the BS to the surface of the measuring section and the determined values of the angles of evolution of azimuth, roll and pitch (current map).

In each measurement cycle, for all hypotheses inside the uncertainty square, the term of the proximity indicator of the current and reference maps is calculated.

At the end of all measurements, an extremum of the proximity indicator is searched.

Corrections to the coordinates of the DO location are determined by the planned coordinates of the measuring section and height.

Corrections are given to the coordinates of the DO location in the planned coordinates of the measuring section in three coordinates, taking into account the angles of evolution.

They control the movement of DO by correcting its location in three coordinates (planned and height).

The motion of the DO is carried out at the rate of receipt of the measured information, but with higher accuracy, since, as the measured section is passed, the location of the DO is corrected taking into account amendments to the working angles of evolution.

Consider the proposed algorithm in more detail.

In each measurement cycle, five beams are used (Fig. 1), which give five values of range and four values of Doppler frequencies (the central beam gives a zero frequency).

In the absence of angles of evolution of DO, when α _T = α _K = α _A = 0, the values of Doppler frequencies for all side rays are equal to each other and are defined as F _D. In FIG. 4-6, this frequency is indicated by black dots.

In the presence of angles of evolution of DO, the values of the Doppler frequencies for each ray change (they shift):

- under the action of the pitch angle, when α _T ≠ 0, for zero roll angles and azimuth α _K = α _A = 0, the points of intersection of the rays with the surface shift relative to the direction of movement (Fig. 4); Doppler frequencies take the values indicated by black triangles with numbers 1-4;

- under the action of the angle of heel, when α _K ≠ 0, for zero values of the pitch and azimuth angles α _T = α _A = 0, the points of intersection of the rays with the surface shift relative to the direction of movement (Fig. 5); Doppler frequencies take the values indicated by black triangles with numbers 1-4;

- under the action of the azimuth angle, when α _A ≠ 0, for zero roll angles and pitch α _K = α _T = 0, the points of intersection of the rays with the surface shift relative to the direction of movement (Fig. 6); Doppler frequencies take the values indicated by black triangles with numbers 1-4.

The direction of the shift in the values of the Doppler frequencies (up-down, right-left, etc.) is determined by the sign of the corresponding evolutionary angle (Fig. 4-6).

By shifting (changing) the array of measured Doppler frequencies (Fig. 4-6) relative to the array of Doppler frequencies corresponding to zero values of the angles of azimuth, roll and pitch, determine and fix the value and sign of the angles of azimuth, roll and pitch at each range measurement cycle. In this case, the measured Doppler frequency is the average value of Doppler frequencies for the period of measurement of one range on the path of the DO along each beam.

The shift (change) of arrays of Doppler frequencies is determined by four side beams in each measurement cycle.

In each measurement cycle, the values and signs of the angles of azimuth, roll and pitch are determined from the database of the dependence of the values and sign of the angles of azimuth, roll and pitch on the change (shift) of the array of values of the measured Doppler frequencies relative to the array of values of the reference Doppler frequencies.

Since the number of rays has changed compared with the prototype, the proximity indicator for the five probing rays is written in the form

- разность измеренных в k-м измерении значений высоты по x (левому или правому) и центральному лучам; $$H_k^{ЦЦ}$$

- разность значений высоты измеренных в k-м и (k-1)-м измерениях по центральному лучу; $$H_{Э,k}^{хЦ}(\cdot )$$

- разность определенных для некоторой гипотезы (для определенного значения n_hx и n_hy) значений высоты по данным эталонной карты на k-м измерении по х (левому или правому) и центральному лучам; $$H_{Э,k}^{ЦЦ}(\cdot )$$

- разность определенных для некоторой гипотезы значений высоты по данным эталонной карты на k-м и (k-1)-м измерениях по центральному лучу.Here we use the notation: PLC - the first left-central (rays), PLC - the first right-central (rays), VLC - the second left-central (rays), VPC - the second right-central (rays), CC - the central-central rays and indicated: n _hx and n _hy - horizontal and vertical offsets of the current map relative to the reference, which are counted from the lower left corner of the reference map, for which n _hx = n _hy = 0; K is the number of measurements; $$H_k^{x\mathrm{Ts}}$$

- the difference of the values of height measured in the kth measurement along x (left or right) and the central rays; $$H_k^{\mathrm{Ts}\mathrm{Ts}}$$

- the difference in the values of the height measured in the k-th and (k-1) -th measurements along the central beam; $$H_{E,k}^{x\mathrm{Ts}}(\cdot )$$

- the difference of the height values determined for a certain hypothesis (for a specific value of n _hx and n _hy ) according to the data of the reference map on the kth dimension along x (left or right) and central rays; $$H_{E,k}^{\mathrm{Ts}\mathrm{Ts}}(\cdot )$$

- the difference of the height values determined for a certain hypothesis according to the data of the reference map at the k-th and (k-1) -th measurements along the central ray.

The degree of influence of evolution angles on the Doppler frequency can be estimated. In the absence of evolution angles α _T = α _K = α _A = 0, the Doppler frequency will be equal to the constant F _Д0 = const, which is determined by the velocity of the DO, the wavelength of the emitted radio waves, and the angle of deviation of the direction of radiation from the DO velocity vector. So, at a DO speed of 330 m / s, a radiation frequency of 10 GHz, for horizontal flight, for an angle between side beams and a vertical of 10 ° and in the absence of DO angles of evolution, the Doppler frequency will be 22 kHz.

The deviation of the Doppler frequency at α _T = α _K = 0 and α _A = 10 ° will be 900 Hz, the deviation of the Doppler frequency at α _T = α _K = 0 and α _A = 1 ° will be 70 Hz, the deviation of the Doppler frequency at α _T = α _K = 0 and α _A = 0.1 ° will be 7 Hz. Modeling of the considered algorithm, as well as analysis of the state of modern technology showed that the method allows to identify the values of the angles of evolution when they change by 0.1 °.

It is important to note that the considered method of DO navigation with the proposed algorithm retains its positive properties even with a greater number of radio waves (the central beam remains one, and the number of side rays from the left and right relative to the central one increases and can be two, three, and so on). ) Moreover, by obtaining additional information on Doppler frequencies, the accuracy of determining the angles of evolution is increased. The number of used rays of radio waves is determined only by the time during which it is possible to measure the location of DO when moving above a measured surface area.

Thus, the method of navigation of moving objects has a number of significant advantages over the analogue and prototype, since the navigation accuracy is significantly improved - the accuracy of determining corrections to DO coordinates by three coordinates is increased by taking into account the action of DO angles of evolution - azimuth, roll and pitch during DO movement.

The motion of the DO is controlled at the rate of receipt of the measured information, but with higher accuracy, since, as the measured section passes, the location of the DO is corrected taking into account the emerging angles of DO evolution.

LITERATURE

1 Patent No. 2338158 of the Russian Federation. IPC G01C 21/00 (2006.01). Aircraft navigation method / Khrustalev A.A., Koltsov Yu.V. Egorov S.N. // Inventions. Useful models. - 2008. - Publ. 11/10/2008. - Bull. No. 31.

2 GOST 20058-80. The dynamics of the aircraft in the atmosphere. Terms, definitions and designations. - M.: State Committee for Standards, 1980. - 54 C.

3 Patent No. 2471152 of the Russian Federation IPC G01C 23/00 (2006.01), G01S 5/02 (2010.01). Aircraft navigation method / Khrustalev A.A., Koltsov Yu.V. // Inventions. Useful models. - 2012. - Publ. 12/27/2012. - Bull. Number 36. (prototype).

Claims (1)

The method of navigation of moving objects, which consists in using a reference map of the area as a priori information about the navigation field, selecting a plot of the terrain (measured area) located within the reference map, compiling the current map by calculating the planned coordinates of the measured area based on range measurements using the multi-beam measurement mode using radio waves cyclically emitted in the form of rays, of which the central one is emitted first, and then the left and right side ones relative to the central one, determining the difference in the results of multipath measurements, determining the angular oscillations of moving objects by the pitch, comparing the values of the planned coordinates of the current and reference maps, calculating the location of moving objects by the three coordinates of the reference map (planned coordinates and height), calculating the signal for correcting the path of motion, and controlling the movement of moving objects by correction of their location in three coordinates of the reference map (planned coordinates and height) during the movement of moving objects over the measured asthomist, characterized in that when compiling the current map based on range measurements using the multipath mode, the rays of the radio waves are located in two orthogonal planes, each of which is rotated around the central beam by an angle equal to 45 degrees relative to the longitudinal axis of moving objects, and the central beam perpendicular to the longitudinal axis of moving objects, and the rays of the radio waves are grouped so that to the same orthogonal plane the first beam belongs to the center, the left rays are side, located in front of the central beam, and the right side rays, located behind the central beam, and to the other orthogonal plane belong the first central beam, the left side rays, located behind the central beam, and the right side rays, located in front of the central beam in the direction of movement of moving objects, and the side rays belonging to the same plane are pairwise symmetrical with respect to the central beam; the calculation of the correction signal for the trajectory of movement of moving objects is carried out taking into account, in addition to the angle tan drywall, azimuth and roll angles, and the evolution angles - azimuth, roll and pitch are determined in dynamics based on the analysis of the Doppler frequencies arising from the measurements of ranges for each beam; to analyze the Doppler frequencies, an array of Doppler frequencies obtained from the Doppler frequencies is used left and right lateral rays for each orthogonal plane for each cycle of the multi-beam measurement mode, and the value and sign of the angles of azimuth, roll and pitch for each measurement of ranges determine the put We compare the measured array of Doppler frequencies with the array of Doppler frequencies corresponding to zero azimuth, roll and pitch angles for each of the lateral rays of the orthogonal planes, respectively.

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