RU2471152C1 - Method of aircraft navigation - Google Patents

Abstract

FIELD: instrument making.

SUBSTANCE: invention may be used to build various radiolocating or similar systems designed for navigation of aircrafts (AC) by detection of location and control of AC movement. A reference area map is used, which has been made prior to start of AC movement, a measured section of the reference map area is selected, the current map is made - parameters are measured on the measured section of the reference map with the help of radio waves emitted in the form of beams. At the same time produced values of current and reference maps of the measured section are compared, indices of data proximity are calculated, errors of measurements are identified on the basis of assessment of an error of AC angular oscillations measurement by pitch, confirmed values of a correction signal by planned coordinates and altitude are detected, AC movement control is carried out on the basis of correction of their location as the appropriate measured section is travelled through.

EFFECT: improved accuracy.

7 cl, 4 dwg

Description

The invention relates to the field of radar technology and can be used in the construction of various radar or similar systems designed to determine the location of aircraft using radio waves and control the movement of aircraft.

To ensure the navigation of aircraft (LA) determine the location of the aircraft by measuring their current coordinates. The location of the aircraft is determined using radio waves for use in radar navigation systems.

Radar navigation systems are based on the correlation-extreme navigation methods (KESN), which ensure the search and tracking of the optimal flight mode of the aircraft [1]. KESN provide the measurement of indicators of the extreme regime of the aircraft, the processing of this information and the development of the control action to correct the coordinates of the location of the aircraft. Most often they use map-matching KESN according to geophysical fields, based on a comparison of current maps of the area obtained using radio waves with reference maps of the same area, a priori located on the aircraft, based on determining the location of the aircraft and then controlling the movement of the aircraft by correcting their location. Reference cards are installed on the aircraft until the start of movement over a given surface area, and current cards are received during the movement of the aircraft. The deviation of the reference terrain maps from the current at a given point trajectory of the aircraft determines the deviation of the actual trajectory from the given. As a result of comparing the reference and current terrain maps, corrections to the coordinates of the aircraft are developed to control the movement by correcting the location of the aircraft.

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 movement of the aircraft, difference algorithms are used, based on the calculation of the differences in the measured heights of the current map.

A known method of navigation of aircraft [2], used in correlation-extreme navigation systems and consisting in determining the location of the aircraft using radio waves emitted in the form of a single beam (hereinafter: radio waves in the form of a beam), allows you to take information at the current point.

The implementation of the method [2] is as follows.

Use the information of the reference map of the area about the navigation field of the earth, which is located on the aircraft before the start of movement.

Select a site of terrain (measured area), which is determined by the value of the permissible deviations of the aircraft in range (square of uncertainty).

(индекс «т» принадлежит текущей карте) от ЛА до рельефа мерного участка в i точках (i=1, 2, 3,… N) траектории движения ЛА (трассы

).The heights are measured using a single beam of radio waves.

(the “t” index belongs to the current map) from the aircraft to the relief of the measuring section at i points (i = 1, 2, 3, ... N) the trajectory of the aircraft (track

)

высот

измеренные с помощью радиоволн, от высот H_oi, измеренных бародатчиком (абсолютная высота), в точках i траектории движения ЛАAfter passing the LA measured area, deviations are calculated

heights

measured by radio waves, from the heights H _oi measured by the bar sensor (absolute height), at points i of the aircraft trajectory

после прохождения мерного участка, то есть получают карту высот рельефа мерного участка (плановые координаты мерного участка), для составления которой используют данные о скорости ЛА и угловых колебаниях ЛА (тангаж, крен и курс).Draw up a current map for the measured area based on the calculated elevation heights

after passing the measured area, that is, get a map of the elevation of the relief of the measured area (planned coordinates of the measured area), for compiling which data on the speed of the aircraft and the angular oscillations of the aircraft (pitch, roll and course) are used.

(индекс «э» принадлежит эталонной карте), направленные вдоль мерного участка с шагом j (j=1, 2, 3,… N) поперек мерного участка, соответствующим шагу эталонной карты (плановые координаты эталонной карты).Determined on the basis of a reference map of the terrain of the route

(the index “e” belongs to the reference map) directed along the measured section with a step j (j = 1, 2, 3, ... N) across the measured section corresponding to the step of the reference map (planned coordinates of the reference map).

Combine the current and reference maps of the study area.

и эталонное

значения путем корреляционно-экстремальной обработки реализаций с использованием разностных алгоритмов КЭСН.Compare current

and reference

values by correlation-extreme processing of implementations using KESN difference algorithms.

A signal for correcting the location of the aircraft in three coordinates is calculated based on an analysis of the mutual displacements of the reference and current terrain maps of the measured area.

Control the movement of the aircraft by correcting its location.

In this KESN, the aircraft trajectory is divided into two successive sections: measurement and correction.

The disadvantages of the method [2] are:

generation of a correction signal only after the passage of the entire measured area;

the need to measure the absolute height of the aircraft above the zero level H _{O of the} reference map, and additional calculations are needed to determine the average levels of heights of the measured map and the reference map. Carrying out such calculations does not allow for the operational processing of data during the movement of the aircraft over the measured area;

low accuracy of compiling the current map using a single beam, since in order to measure the height to the studied area, the width of the beam of radio waves should be wide enough. This reduces the accuracy of determining the range to individual points on the surface and, accordingly, decreases the accuracy of compiling the current map;

lack of information about the current location of the aircraft in the process of moving over the measured area, since the processing of the measured information is carried out after the passage of the entire measured area;

low accuracy of calculating the correction signal in three coordinates due to the presence of an error in the data due to the angular oscillations of the aircraft in pitch, which is significant.

A known method of navigation of aircraft [3], selected for the prototype.

The navigation method of the aircraft is as follows.

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

Select the required 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 aircraft in range (uncertainty square).

Make up the current map by measuring the parameters of the measured area using radio waves. Rays of radio waves emit as follows. The first to emit a beam, the propagation direction of which is located in a plane orthogonal to the plane of the horizon of the measured section, or in a plane that is at an angle to the plane of the horizon 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 the aircraft) from the first ray, and the other part to the right (in the direction of the aircraft) from the first ray. The number of rays to the right and left of the first ray is the same.

The location of the aircraft in the planned coordinates of the measured area is calculated based on measurements using beams of radio waves of inclined ranges from the aircraft to the surface of the measured area and the use of data on the speed and angular oscillations of the aircraft (pitch, roll, course).

Calculations are performed similar to those described above, using a reference map for each possible position of the aircraft inside 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.

The corrections to the coordinates of the location of the aircraft in the planned coordinates of the measured area are determined based on an analysis of the mutual displacements of the reference and current terrain maps of the measured area.

After determining the location of the aircraft in the planned coordinates of the measured area, calculate the height of the aircraft above the surface of the measured area in the coordinates of the measured area (at the point of determining the location of the aircraft in the planned coordinates of the measured area) as the sum of the height, which is the value of the measured oblique range, multiplied by the cosine of the angle of inclination of the beam relative to perpendicular to the surface of the measured section, and the correction determined by the reference map, which is the difference in the elevation of the relief of the measured section at the point Nia slant range and a point located on a line perpendicular to the dimensional surface 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 its location in three coordinates: the planned coordinates and the height values to the surface of the measured section as the measured section passes.

The disadvantage of this method [3] is the low accuracy of calculating the correction signal in three coordinates due to the presence of measurement error in the data caused by the measurement error of the aircraft angular oscillations in pitch, which is significant. The fact is that the error in measuring angular oscillations in pitch gives an error in measuring the slant range, which must be taken into account when taking measurements.

The technical result of the invention is to increase the accuracy of the navigation method of aircraft due to the fact that when calculating the position correction signal for controlling the movement of aircraft take into account the error that occurs when moving over the measured area due to the error in measuring the angular oscillations of the aircraft.

The technical result is achieved by the fact that in the method of navigation of aircraft, which consists in using a reference map of the area as a priori information about the navigation field, selecting a plot of terrain (measured section) located within the reference map, compiling the current map by calculating the planned coordinates and the height of the measured section based on measurements of slant ranges using the multipath mode of measurement using radio waves emitted in the form of rays, determining the difference in the results of multipath and measurements, comparing the values of the planned coordinates of the current and reference maps, calculating the signal of the correction of the trajectory of movement and controlling the movement of aircraft by correcting their location, when measuring oblique ranges, measure the integrated parameters of the reflected pulses for each of the rays, and before correcting the location of the aircraft, compare the integral parameters of the measured and reference (a priori information) reflected pulses for each beam, taking into account the type and inclination of the underlying surface , determine the error of multipath measurements caused by the error of measuring the angular oscillations of aircraft by pitch, compare the values of the planned coordinates of the current and reference maps taking into account the error of multipath measurements, calculate the updated value of the correction signal by the planned coordinates and height, compare the integral parameters of the measured and reference reflected pulses for each of the rays is carried out by searching for a reference reflected pulse, the integral parameter of which corresponds to the tegral parameter of the measured reflected pulse, to search for the reflected reference pulse corresponding to the measured parameter of the reflected reflected integral, use the database of the integrated parameters of the reference reflected signals, which is an array of data whose elements digitally store the integrated parameters of the reference reflected pulses, taking into account the type of underlying the surface and the range of angles at which slant ranges to the underlying surface can be measured In particular, the type of underlying surface is determined by the type of underlying surfaces of the cells of the reference card inside the circle, the radius of which depends on the height of the aircraft and the width of the emitted beam, and if the types of cells are different, then choose the type that has the largest number of cells closer to the center of the circle, when determining the angle at which the inclined ranges to the underlying surface are measured, the angle of deviation of each specific beam from the vertical is summed at In the absence of angular oscillations, the pitch angle (a priori known data obtained before multipath measurements), as well as the angle of inclination of the underlying surface, when determining the angle of inclination of the underlying surface, determine the average angle of inclination of the cells of the reference map inside the circle, the radius of which depends on the height of the aircraft apparatus and the width of the emitted beam, to determine the error of multipath measurements, by comparing the integrated parameters of the measured and reference reflected impulses the pulses for each of the rays determine the additional angle of deviation from the vertical of each of the rays, caused by the error in measuring the angular oscillations of the aircraft pitch.

When implemented, the method of navigation of aircraft allows you to specify the location of the aircraft during the correction of the movement of the aircraft during the passage of the measured area with less error.

The navigation method of the aircraft is explained by the following drawings:

- the figure 1 shows the relative position of the coordinate systems during the movement of the aircraft;

- figure 2 presents a part of the surface of the measured area with a grid of a reference card with a step Δ _E , which shows the position of the aircraft, the vertical to the surface of the measured area of LA-A, the line of the measured slant range of the aircraft to the surface of the measured area of LA-B and the angle deviations of the radiation direction when measuring the slant range from the vertical γ ₁ ;

- figure 3 presents: the direction of movement of the aircraft; skyline; a linear profile of the underlying surface, located at an angle γ ₂ (average) with respect to the horizon;

- figure 4 shows two pulses: the first (1) is the reference reflected pulse from the surface of the measured section (figure 1, point A) and the second (2) is the measured reflected pulse from the surface of the measured section (figure 1, point B), received during measurements.

Pulses 1 and 2 (figure 4) have the following parameters: A _MAX1 - the maximum value of the pulse 1; A _MAX2 - maximum value of impulse 2; t ₁ - pulse duration 1 at half its maximum value (0.5 · A _MAX1 ); t ₂ - pulse duration 2 at half its maximum value (0.5 · A _MAX2 ), and t ₂ > t ₁ ; Δt _CM1 - temporary displacement of the maximum of the pulse 1 relative to the level of 10% of its maximum (0.1 · A _MAX1 ); Δt _CM2 - temporary displacement of the maximum of the pulse 2 relative to the level of 10% of its maximum (0.1 · A _MAX2 ); in this case, the temporary displacement of the maximum of the ith pulse Δt _CMi characterizes the change in its shape due to various factors, in this case, this is the influence (presence of γ ₁ ) of the aircraft angular oscillations in pitch.

With this in mind, we define the integral parameter (PI) of the i-th reflected pulse as a set of values of the following values: the maximum value A _{MAXi of the} pulse, the duration of the pulse at half its maximum value t _i , the temporal displacement of the maximum pulse relative to the level of 10% of its maximum Δt _CMi , and write how

The navigation method is implemented as follows.

We will consider the implementation of the aircraft navigation method using the example of compiling the current map using multi-beam measurements using three rays of radio waves located in one plane, which is at an angle to the horizontal plane of the measured section.

During the movement over the measured area, the current map of the area is determined, for the compilation of which data on the measured values of the slant range using the rays of radio waves, as well as the values of the speed and angles of evolution of the aircraft (pitch, roll and course - a priori known data obtained prior to the following measurements). In this case, the pitch data has its own measurement error.

In the analysis, the following coordinate systems are used, shown in FIG. 1, for: a reference map of the terrain (large rectangle in FIG. 1); the square of uncertainty (the square in figure 1); possible positions of the aircraft inside the uncertainty square at the time of the start of measurements (points in FIG. 1) and points of the trajectory of the aircraft at which measurements are made (diamonds in figure 1).

The local coordinate system is the left rectangular Cartesian coordinate system O _r x _r y _r z _r with the origin O _r . In this case, the axes O _r x _r and O _r y _r lie in the plane of the local horizon, that is, x _r and y _r are the planned coordinates of the aircraft. Relative to the plane O _r x _r y _r determine the elevation of the terrain and the aircraft. Thus, the indicated heights are the corresponding values of the coordinate z _r . The origin of the coordinates O _{r is} chosen so that the axis O _r y _{r is} directed to the calculated point of the appearance of the aircraft over the area corresponding to the reference map. The axis O _r y _r is considered collinear with respect to the horizontal component of the calculated velocity vector of the aircraft (Fig. 1). The planned coordinate system is fixed and connected to the reference map.

In order to attach the planned coordinates to the reference map, use a discrete coordinate system. In this case, the axes N _x and N _{y are} aligned with the axes of the local system O _r x _r y _r (Fig. 1). Zero indices in the discrete coordinate system correspond to the lower left corner of the reference map. The estimated value of the discrete coordinates of the aircraft at the time of the start of data collection O _{r is} denoted as (n _xrЭ , n _урЭ ).

The relationship between the coordinates of the discrete and local coordinate systems is determined by expressions of the form

where Δ _E is the grid cell size of the reference card.

When determining the coordinates of the measurement points in the form of intersection points of the underlying surface and the rays of the radio waves, a coordinate system is used that is associated with the current position of the aircraft. The origin of this system (point O _a ) will be placed at the current projection point of the aircraft trajectory on the plane of the planned coordinates. On the x axis _and the direction _and coincides with the current direction of the aircraft velocity vector.

The relationship between the coordinates of the system associated with the aircraft, and the local coordinate system is determined by the expressions

where x _rc and y _rc are the coordinates of the projection of the current position of the aircraft on the plane of the planned coordinates; α _x - the course of the aircraft at the current measurement point (the angle between the velocity vector of the aircraft and the axis O _r x _r ).

The initial data for calculations in KESN are:

- a reference map, which is an array of terrain data, the elements of which are the elevations in the nodes of the coordinate grid of the reference map on the plane O _r x _r y _r , and an array of data on the type of underlying surface, the elements of which are symbols for the types of underlying surfaces between the nodes of the coordinate grid of the reference map on the plane O _r x _r y _r ;

- a database of integrated parameters of the reference reflected signals, which is an array of data whose elements digitally store the values of the integrated parameters of the reference reflected pulses, taking into account the type of the underlying surface and the range of angles at which the inclined ranges to the underlying surface can be measured;

- integrated parameters of the measured reflected pulses;

- data determined by the angle between the rays α _{R of the} radio waves;

- measurement data, different from those obtained with the help of the rays of radio waves, arriving with each measurement result: values of the angle α _{Z of the} roll, angle α _{x of the} course, angle α _{t of} pitch, speed ν of the aircraft;

- the current map, which is a set of values of inclined ranges for all three rays received in each dimension.

The current terrain map is determined by the matrix N (n _x , n _y ) of size N _x × N _y , and the reference map is determined by the matrix N _E (n _x , n _y ) of size N _{x E} × N _uE . The discrete values of n _sx and n _sy correspond to the horizontal and vertical displacement of the current map relative to the reference and are counted from the lower left corner of the reference map, for which n _sx = n _sy = 0.

In the proposed method, a differential-difference algorithm for processing multipath measurements is used, which we will consider using the example of a three-beam KESN. Rays of radio waves emit sequentially in the following order: the first is the central beam (in the direction of movement of the aircraft), the second is the left beam and the third is the right beam relative to the central beam.

The slant ranges and integrated parameters of the reflected signals (measured signals) for each beam are measured.

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. Using the reference map for each hypothesis, the position of the coordinates at each point is determined, for which the elevation of the terrain in the measured area is calculated.

Data processing for each measurement is as follows.

Based on the data on inclined ranges, as well as on angular oscillations of the aircraft, the coordinates of the measurement points are calculated in the coordinate system associated with the aircraft.

The local coordinates of the projection of the point of the trajectory of the aircraft on the plane of the planned coordinates and the height of the aircraft above the surface of the measured area in the coordinates of the measured area are calculated.

For each hypothesis, that is, for all possible positions of the aircraft inside the uncertainty square, one term of the proximity indicator is calculated.

It should be noted that the presence of measurement errors due to angular oscillations of the aircraft in pitch (Fig. 2, angle γ ₁ ) leads to an additional error in determining corrections to the coordinates, to eliminate which the following operations are performed.

Measure and remember the integrated parameters (PI) of the measured reflected signals for all three rays in the last measurement.

On the reference map, the average angle of inclination of the surface (Fig. 3, angle γ ₂ ) and the type of underlying surface for each of the rays in the last measurement are determined from the previously determined measurement points in the local coordinate system.

A database is used about the integrated parameters of the reference reflected signals for three rays, 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 aircraft by pitch using the integral parameters of the reference and measured reflected signals for each beam.

Search for the extremum of the proximity indicator. The proximity index of data P (n _hx , n _hy ) for this case can be written as

- разность измеренных в k-м измерении значений высоты по первому и левому лучам;

- разность измеренных в k-м измерении значений высоты по первому и правому лучам;

- разность значений высоты измеренных в k-м и (k-1)-м измерениях;

- разность определенных для некоторой гипотезы (для определенного значения n_hx и n_hy) значений высоты по данным эталонной карты на k-м измерении по первому и левому лучам;

- разность определенных для некоторой гипотезы значений высоты по данным эталонной карты на k-м измерении по первому и правому лучам;

- разность определенных для некоторой гипотезы значений высоты по данным эталонной карты на k-м и (k-1)-м измерениях по первому лучу.Here n _hx and n _hy are the displacements of the point O _r for various hypotheses; K is the number of measurements;

- the difference of the height values measured in the k-th measurement on the first and left rays;

- the difference of the height values measured in the k-th measurement on the first and right rays;

- the difference in height values measured in the k-th and (k-1) -th dimensions;

- 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 in the kth dimension according to the first and left rays;

- the difference of the height values determined for a certain hypothesis according to the data of the reference map in the kth dimension according to the first and right rays;

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

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

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

Control the movement of the aircraft by correcting its location in three coordinates (planned and height) as the measured area passes.

Consider this algorithm as an example of the first ray.

The presence of an error in the measurements caused by the error in measuring the angular oscillations of the aircraft in pitch (FIG. 2) gives a measurement error in range, which reduces the accuracy of determining corrections to the coordinates of the location of the aircraft.

If the measurement error due to the error in measuring the angular oscillations of the aircraft in pitch is absent, for example, when the first beam is directed vertically down and the underlying surface is horizontal (Fig. 2, along the A-LA line), then the measured reflected signal coincides in shape with the reference reflected signal.

If there is a deviation of the first beam from the vertical (Fig. 2 along the B-LA line), the inclination of the underlying surface with respect to the vertical (Fig. 3), and a specific shape of the backscatter pattern (DOR, which characterizes the type of surface (the degree of its roughness) and has a strong dependence on the angle of incidence of the beam on it [4]), the integrated parameter of the reflected signal changes (as defined by expression (2)), which characterizes the change in its shape: the amplitude of the measured reflected signal decreases, and its duration increases with equal to the reference, therefore, the temporal shift of the maximum of the measured reflected pulse relative to the level of 10% of its maximum by Δt _CM2 (Fig. 4) is compared with the time offset of the maximum of the reference reflected pulse relative to the level of 10% of its maximum Δt _CM1 (Fig. 4).

Let us consider the influence on the error of three-beam measurements of the error in measuring the angular oscillations of an aircraft by pitch using the following example. The effect of the error in measuring the angular oscillations of the aircraft by pitch is manifested in the fact that the integral parameter of the measured reflected pulse will be determined by the sum of the following angles: the average angle of inclination of the underlying surface, the angle of deviation from the vertical pitch (known a priori) and the additional angle of deviation from the vertical pitch caused by the error in measuring the angular oscillations of the aircraft in pitch.

If the type of the underlying surface, the angle of inclination of the underlying surface and the angle of deviation from the vertical along the pitch are known, then from the measured temporal displacement of the maximum of the measured reflected pulse and its duration at half the maximum value, using the database on the integrated parameters of the reference reflected pulses, you can determine the additional angle pitch deviation of the beam - the angle that determines the measurement error caused by the measurement error of the aircraft angular oscillations in pitch.

Let us consider in detail the algorithm for determining the measurement error due to the error in measuring the aircraft angular oscillations in pitch.

Remember the temporary position of the maxima and the duration at half the maximum value of the measured reflected pulses for all three rays during the last measurement before searching for the extremum of the proximity indicator.

Using the reference map, the average angle of inclination and the type of underlying surface for each of the rays in the last measurement before searching for the extremum of the proximity indicator are determined from the previously determined measurement points in the local coordinate system. The desired underlying surface may include from 1 to M cells of the reference map, the number of which is determined by the diameter of the circle, the radius of which depends on the height of the aircraft and the width of the emitted beam. In this case, cells of the reference map are considered, in which at least half of the area is inside the specified circle.

Determine the average angle of inclination of the desired underlying surface on the reference map relative to the horizontal after determining the location of the aircraft on the reference map (figure 3).

The type of the underlying underlying surface is determined from the reference map — by the types of cells of the reference map included in the desired underlying surface. Moreover, if the types of cells are different, then choose the type that has the largest number of cells located closer to the center of the circle.

When determining the angle of inclination of the underlying surface, the average angle of inclination of the cells of the reference card inside the circle, the radius of which depends on the height of the aircraft and the width of the emitted beam, is determined.

Using the database, the values of the temporal positions of the maxima and the duration at the level of their half maximum value (integral parameters) of the reference reflected pulses for each of the rays, taking into account the specific type and average angle of inclination of the underlying surface.

The angle of deviation from the vertical is determined by the pitch of each of the rays of the radio waves by searching the database of the reference reflected pulse, the integral parameter of which corresponds to the integral parameter of the measured reflected pulse and determining the angle of deviation from the vertical by pitch. In the database, for each reference reflected pulse, the pitch deviation angle from the vertical is determined. The obtained angle of deviation from the vertical of each of the rays (the angle at which the inclined ranges to the underlying surface are measured) includes the angle of deviation of each specific beam from the vertical in the absence of angular oscillations and the pitch angle (a priori known data obtained before multipath measurements), the average angle of inclination of the underlying surface, as well as the additional angle caused by the error in measuring the pitch angle angular vibrations.

Find the value and direction (left or right of the aircraft motion direction) of the additional pitch angle by vector subtraction from the obtained angle of deviation from the vertical for each of the rays, the angle of deviation of each specific beam from the vertical in the absence of angular vibrations, pitch angle and angle of inclination of the underlying surface.

Determine the average value of the additional angle caused by the error in measuring the angular oscillations of the aircraft by pitch, by averaging these values for each of the rays.

On the basis of certain values and directions of the additional angle in terms of pitch, the corrections to the coordinates of the aircraft are determined according to the planned coordinates.

When conducting these operations, it was assumed that the calculation of all components and the extremum of the proximity indicator is obtained after completion of all measurements, the calculation of which used the difference in elevation values (as in the prototype). The presence of an error in measuring the angular oscillations of the aircraft by pitch leads to the fact that instead of heights, in this case, inclined ranges are used, and the location of the aircraft is shifted in space relative to the reference map.

The refinement of corrections to the coordinates of the aircraft according to the planned coordinates leads to a shift in the extremum of the proximity indicator of the data on the reference map in the direction specified by the direction of the additional pitch angle by a value determined earlier by the aircraft altitude and the tangent of the additional pitch angle.

The updated aircraft height 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 aircraft in the planned coordinates of the measured area) as the sum of the height, which is the value of the measured slant range, multiplied by the cosine of the angle of inclination of the beam relative to the perpendicular to the surface of the measured area, taking into account the additional pitch angle, and the correction determined by the reference map, which is the difference in the elevation of the relief of the measuring section at the point of definition of the inclined to the point and the point located on the line of the perpendicular to the surface of the measuring section.

Corrections are given to the coordinates of the location of the aircraft in the planned coordinates of the measuring area in three coordinates and the updated value of the correction signal is determined.

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

The movement of the aircraft is controlled at the rate of receipt of the measured information, but with higher accuracy, since as the measured section is passed, the location of the aircraft is corrected in three coordinates, taking into account corrections for errors during measurements due to the error in measuring the angular oscillations of the aircraft by pitch.

The modeling of the considered algorithm showed that taking into account the error in measuring the angular oscillations of the aircraft by pitch of units of degrees allows us to reduce the error in determining corrections to the coordinates of the aircraft from the planned coordinates by at least two times. This significantly improves the accuracy of navigation.

It is important to note that the considered method of aircraft navigation with the proposed algorithm retains its positive properties with a different number of radio waves. The number of used rays of radio waves is determined only by the time during which the measurement of the location of the aircraft when moving above the measured surface area is provided.

Thus, the aircraft navigation method has a number of significant advantages over the analogue and prototype, since it significantly increases navigation accuracy (improves the accuracy of determining corrections to the coordinates of the aircraft in three coordinates) by taking into account the error in measuring the angular oscillations of the aircraft by pitch, which in practice have the greatest impact on measurement error.

LITERATURE

1. Beloglazov I.N., Dzhandzhgava G.I., Chigin G.P. Fundamentals of navigation through geophysical fields. - M .: Nauka, 1985 .-- 328 p. (p. 10-11, 19-22, 25-34).

2. Rzhevkin V.A. Autonomous navigation on terrain maps // Foreign Radio Electronics. - 1981. - No. 10. - S. 3-28.

3. 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. // Retrospective set of descriptions of inventions for 2008 on DVD (Publ. 10.11.2008. - Bull. No. 31) (prototype).

4. Finkelstein M.I. Basics of radar. - M .: Radio and communications, 1983 .-- 536 p. (p.186, 126-129).

Claims (7)

1. The method of navigation of aircraft, 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) within the reference map, compiling the current map by calculating the planned coordinates and the height of the measured area based on measurements of inclined ranges using the multipath measurement mode using radio waves emitted in the form of rays, determining the difference in the results of multipath measurements, comparing the values of the planned coordinates nat current and reference maps, calculating the signal of the correction of the trajectory of motion and controlling the movement of aircraft by correcting their location, characterized in that when measuring inclined ranges, the integrated parameters of the reflected pulses are measured for each of the rays, and before correcting the location of the aircraft, the integrated parameters of the measured and the reference (a priori information) reflected pulses for each beam, taking into account the type and inclination of the underlying surface, determine the error s multipath measurement, the measurement error caused by the angular oscillation of aircraft pitch attitude, the comparison is carried plane coordinates and the reference current value cards with the multipath error of measurements, calculating a corrected value of the coordinates and planned altitude correction signal. 2. The method according to claim 1, characterized in that the comparison of the integrated parameters of the measured and reference reflected pulses for each of the rays is carried out by searching for a reference reflected pulse, the integral parameter of which corresponds to the integrated parameter of the measured reflected pulse. 3. The method according to claim 2, characterized in that to search for a reflected reference pulse corresponding to the measured reflected pulse in terms of the integrated parameter, a database is used about the integrated parameters of the reference reflected signals, which is an array of data whose elements digitally store the integral parameters of the reference reflected pulses taking into account the type of underlying surface and the range of angles at which slant ranges to the underlying surface can be measured. 4. The method according to claim 1, characterized in that the type of underlying surface is determined by the type of underlying surfaces of the cells of the reference card inside a circle whose radius depends on the height of the aircraft and the width of the emitted beam, and if the types of cells are different, then select that type which has the largest number of cells closer to the center of the circle. 5. The method according to claim 1, characterized in that when determining the angle at which the inclined ranges to the underlying surface are measured, the angle of deviation of each specific beam from the vertical in the absence of angular oscillations and the pitch angle are summed up (a priori known data obtained before multipath measurements), as well as the angle of inclination of the underlying surface. 6. The method according to claim 5, characterized in that when determining the angle of inclination of the underlying surface, the average angle of inclination of the cells of the reference card inside the circle, the radius of which depends on the height of the aircraft and the width of the emitted beam, is determined. 7. The method according to claim 1, characterized in that for determining the error of multipath measurements, by comparing the integrated parameters of the measured and reference reflected pulses for each of the rays, an additional angle of deviation from the vertical of each of the rays is determined, caused by the error in measuring the angular oscillations of aircraft the pitch.

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