RU2543064C1 - Method of generating error signals when controlling movement of object to guide said object to given point - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: result is achieved by reducing the size of antennae used, which considerably reduces the weight and overall dimensions of landing support systems compared to existing instrument landing systems.

EFFECT: improved weight and size characteristics of the system.

4 dwg

Description

The invention relates to radio navigation systems and can be used in systems for ensuring the landing of aircraft, including unmanned ones, as well as in navigation support systems. In addition, the invention can be used to ensure the automatic return of a fireman or other robot, to ensure targeted landing of people or cargo, to ensure targeted discharge of water when fighting fires.

Known methods for generating an error signal used in radio engineering systems for landing aircraft to ensure the movement of the aircraft along a given path of descent and landing. [Bakulev P.A., Sosnovsky A.A. Radio navigation systems. - M .: Radio engineering, 2011, p. 159-181].

To implement the known methods, an aircraft (LA) is irradiated with radio signals, on board the aircraft, signals are received and converted into signals of angular deviations from a given path. Signal parameters containing information on the angular deviations of the aircraft are formed using special beacon antennas. Typically, a radio landing system consists of two independent channels (course and glide path).

The closest analogue of the proposed method is an equal-signal method for determining deviations from a given trajectory [Bakulev P.A., Sosnovsky A.A. Radio navigation systems. - M .: Radio engineering, 2011, p. 161-170]. This method is used in each of the two (course and glide path) channels.

In particular, to control the movement of the aircraft at the heading, an exchange directional beacon located on the axis of the runway is used.

Two amplitude-modulated signals with the same carrier frequency are formed, which differ in modulation frequencies F ₁ and F ₂ . For these two signals, two fixed intersecting radiation patterns of the antenna system of the beacon are formed. The beacon direction corresponding to the intersection of the radiation patterns is directed along the course line, that is, along the axis of the runway. An aircraft is irradiated with an antenna system by two amplitude-modulated signals. On board the aircraft, beacon signals are received and detected. The deviation signal from the course line (error signal) is formed depending on the difference in amplitudes obtained as a result of detection of the signals of frequencies F ₁ and F ₂ .

A disadvantage of the known equal-signal method is the need to use highly directional antenna systems. This leads to the significant dimensions of the antenna systems, their considerable mass, to the need for cumbersome load-bearing structures and foundations for them, as well as to the impossibility of rapid deployment of the antenna system.

The invention is aimed at solving the problem of generating an error signal while ensuring the output of the object to a given point without the use of highly directional antennas, which improves the overall dimensions of the system and significantly reduces the time for its deployment.

The formation of an error signal when controlling the movement of an object in order to output the object to a given point occurs as follows.

The first and second main signals of unequal frequencies and a shift frequency signal are generated.

The first main signal and the shift frequency signal are converted in the frequency converter into a first additional signal whose frequency is shifted relative to the frequency of the first main signal by the frequency of the shift signal.

The second main signal and the shift frequency signal are converted in the frequency converter into a second additional signal, the frequency of which is shifted relative to the frequency of the second main signal by the frequency of the shift signal.

At the control object, the main signals are received and converted into a main differential frequency signal, and additional signals are received and converted into an additional differential frequency signal.

At the moment of starting the motion control of the object, the initial value of the phase difference of the main and additional signals of the difference frequency is determined.

In subsequent moments, the current values of the phase difference of the main and additional signals of the difference frequency are determined and error signals are generated depending on the deviations of the current values of the phase difference of the main and additional signals of the difference frequency from the initial value of the phase difference of the main and additional signals of the difference frequency.

An example implementation of the proposed method is described with reference to figure 1, figure 2, figure 3 and figure 4.

Figure 1 presents a vector diagram that allows you to determine the spatial arrangement of the lines of equal phase differences of the main and additional signals of the differential frequency.

In figure 1, the following notation is used:

A ₁ - transmitting antenna of the first beacon emitting a frequency signal ω ₁ ;

A ₂ - transmitting antenna of the second beacon emitting a frequency signal ω ₂ ;

M is the point near which the trajectory of the control object must pass (given point);

ОУ - control object;

r ₁ , r ₂ - vectors whose beginnings are at the points of location of the antennas A ₁ and A ₂ , and the ends are at the point of location of the control object;

β is the angle between the vectors r ₁ and r ₂ ;

B is the bisector of angle β;

, $$r_2^0$$

- орты векторов r₁ и r₂. $$r_{\mathrm{one}}^0$$

, $${\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="00000019.png"\; state="\{\{state\}\}">r</figure-callout>}}_2^0$$

- unit vectors of r ₁ and r ₂ .

Figure 2 shows the lines of equal phase differences of the main and additional signals of the difference frequency and the trajectory of the control object.

In figure 2, the following notation is used:

A ₁ - the location point of the antenna of the first beacon;

A ₂ - the location point of the antenna of the second beacon;

L ₁ , L ₂ , L ₃ , ..., L _N - lines of equal phases of the signal of the differential frequency;

T is the trajectory of the control object;

M ₀ - the point at which the control object was at the time of the beginning of the control of the movement of the object;

L ₀ - line of equal phases passing through the point M ₀ ;

M is the point near which the trajectory of the control object must pass (given point);

V ₀ is the velocity vector of the control object at the time the control begins.

Figure 3 shows a variant of the functional diagram of the signal generation of beacons.

In figure 3, the following notation is used:

PM ₁ - the first beacon;

PM ₂ - the second beacon;

A ₁ - transmitting antenna of the first beacon emitting signals of frequencies ω ₁ and ω _2dop ;

A ₂ - transmitting antenna of the second beacon emitting a signal of frequency ω ₂ and ω _{1 add.}

Figure 4 shows a variant of the functional diagram of the onboard part of the system for generating an error signal.

In figure 4, the following notation is used:

A _main - the antenna of the receiver of the main signals of frequencies ω ₁ and ω ₂ ;

A _add - receiver antenna of additional signals of frequencies ω _1dop and ω _2dop .

The formation of the error signal is as follows.

Form the first and second main signals of unequal frequencies ω ₁ and ω ₂ and the signal of the shear frequency ω _shear . Signal generation can be performed in a frequency synthesizer, as shown in Fig.3.

The instantaneous values ψ ₁ (t) and ψ ₂ (t) of the phases of the main signals are determined by the expressions:

ψ ₁ (t) = ω ₁ t-ψ ₀₁ ;

ψ ₂ (t) = ω ₂ t-ψ ₀₂ ,

where t is the current time;

ψ ₀₁ is the initial phase of the first main signal;

ψ ₀₂ is the initial phase of the second main signal.

The instantaneous values of the _shift ψ (t) of the phase of the shear frequency signal are determined by the expression:

ψ _shear (t) = ω _shear t-ψ _{0 shear} ,

where ψ _{0 shear} is the initial phase of the shear frequency signal.

The first main signal and the shift frequency signal are supplied to the frequency converter and converted into a first additional signal, the frequency ω _{1 of} which is shifted relative to the frequency of the first main signal by the frequency of the shift signal. The shift can occur either with an increase in frequency or with its decrease. In particular, the frequency of the first additional signal may be, as shown in FIG. 3, equal to the sum of the frequencies:

ω _1dop = ω ₁ + ω _shift .

The second main signal is likewise converted into a second additional signal, the frequency ω _{2dop of} which in this example is determined by the expression:

ω _2dop = ω ₂ + ω _shift .

The instantaneous value ψ _1dop (t) of the phase of the first additional signal, up to a constant phase shift, is equal to the sum of the phases of the first main signal and the shift frequency signal:

ψ _{1 add} (t) = (ω ₁ + ω _shift ) t- (ψ ₀₁ + ψ _{0 shift} + ψ _{1 convert} ),

where ψ _{1 transform} is an additional phase shift when converting the first main signal to the first additional one.

The instantaneous value ψ _2dop (t) of the phase of the second additional signal, up to a constant phase shift, is equal to the sum of the phases of the second main signal and the signal of the shift frequency:

ψ _2dop (t) = (ω ₂ + ω _shift ) t- (ψ ₀₂ + ψ _0shift + ψ _2conversion ),

where ψ _2convert is an additional phase shift when converting the second main signal to the second additional one.

Near a predetermined point M (see FIG. 1), a first beacon emitting a first primary and second additional signals and a second beacon emitting a second primary and first additional signals are arranged.

At the control object, the main signals are received and converted into the main signal of the difference frequency (ω ₁ -ω ₂ ). Reception and conversion can be done in various ways. In particular, as shown in Fig. 4, the reception of both main signals can be performed by a single receiver of the main signals, and the conversion of the received main signals into the main signal of the difference frequency can occur in the amplitude detector.

The instantaneous values ψ _1prin (r, t) and ψ _2prin (r, t) of the phases of the received main signals of the beacons depend on the frequencies ω ₁ and ω ₂ and on the distances r ₁ and r ₂ from the corresponding transmitting antennas to the control object:

; $${\psi }_{\mathrm{one}PR\mathrm{and}n}(r,t)={\omega }_{\mathrm{one}}t-\frac{{\omega }_{\mathrm{one}}}{c}{r}_{\mathrm{one}}-{\mathrm{<figure-callout\; id="01"\; label="\psi "\; filenames="00000019.png"\; state="\{\{state\}\}">\psi </figure-callout>}}_{01}$$

;

, $${\psi }_{2PR\mathrm{and}n}(r,t)={\omega }_{2}t-\frac{{\omega }_2}{c}{r}_2-{\mathrm{<figure-callout\; id="02"\; label="\psi "\; filenames="00000019.png"\; state="\{\{state\}\}">\psi </figure-callout>}}_{02}$$

,

where r is the vector of the current coordinates of the control object;

c is the speed of light.

The instantaneous value ψ of the _{main difference} (r, t) of the phase of the main signal of the difference frequency, up to a constant phase shift, is equal to the phase difference of the received main signals:

, $${\psi }_{\mathrm{about}\mathrm{from}n.R\mathrm{but}sn}(r,t)=\left({\omega }_{\mathrm{one}}-{\omega }_2\right)t-\frac{\mathrm{one}}{c}\left({\omega }_{\mathrm{one}}{r}_{\mathrm{one}}-{\omega }_2{r}_2\right)-\left({\psi }_{01}-{\psi }_{02}\right)-{\psi }_{PRe\mathrm{about}bR.\mathrm{about}\mathrm{from}n}$$

,

where ψ _{preobr. DOS} - an additional phase shift when converting to the main signal of the difference frequency.

Additional signals are received and converted into an additional differential frequency signal.

, соответствующую расстоянию r₂ от антенны второго радиомаяка до объекта управления:The instantaneous phase values of the received first additional signal differ from the instantaneous values ψ _1dop (t) of the phase of the first additional signal emitted by the second beacon by an amount $$\frac{\left({\omega }_{\mathrm{one}}+{\omega }_{\mathrm{from}d\mathrm{at}\mathrm{and}g\mathrm{but}}\right)}{\mathrm{<figure-callout\; id="2"\; label="c\; r"\; filenames="00000019.png"\; state="\{\{state\}\}">c\; </figure-callout>}}{r}_{}{}_2$$

corresponding to the distance r ₂ from the antenna of the second beacon to the control object:

. $${\psi }_{\mathrm{one}d\mathrm{about}P.PR\mathrm{and}n}(t)=\left({\omega }_{\mathrm{one}}+{\omega }_{\mathrm{from}d\mathrm{at}\mathrm{and}g\mathrm{but}}\right)t-\frac{\left({\omega }_{\mathrm{one}}+{\omega }_{\mathrm{from}d\mathrm{at}\mathrm{and}g\mathrm{but}}\right)}{c}{r}_2-\left({\mathrm{<figure-callout\; id="01"\; label="\psi "\; filenames="00000019.png"\; state="\{\{state\}\}">\psi </figure-callout>}}_{01}+{\psi }_{0\mathrm{from}d\mathrm{at}\mathrm{and}g\mathrm{but}}+{\psi }_{\mathrm{one}PRe\mathrm{about}bR}\right)$$

.

, соответствующую расстоянию r₁ от антенны первого радиомаяка до объекта управления:Instantaneous values ψ _{2dop. the received} (r, t) phases of the received second additional signal differ from the instantaneous values ψ _2dop (t) of the phase of the second additional signal emitted by the first beacon by $$\frac{\left({\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="00000019.png"\; state="\{\{state\}\}">\omega </figure-callout>}}_2+{\omega }_{\mathrm{from}d\mathrm{at}\mathrm{and}g\mathrm{but}}\right)}{c}{r}_{\mathrm{one}}$$

corresponding to the distance r ₁ from the antenna of the first beacon to the control object:

. $${\psi }_{2d\mathrm{about}P.PR\mathrm{and}n}(t)=\left({\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="00000019.png"\; state="\{\{state\}\}">\omega </figure-callout>}}_2+{\omega }_{\mathrm{from}d\mathrm{at}\mathrm{and}g\mathrm{but}}\right)t-\frac{\left({\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="00000019.png"\; state="\{\{state\}\}">\omega </figure-callout>}}_2+{\omega }_{\mathrm{from}d\mathrm{at}\mathrm{and}g\mathrm{but}}\right)}{c}{r}_{\mathrm{one}}-\left({\mathrm{<figure-callout\; id="02"\; label="\psi "\; filenames="00000019.png"\; state="\{\{state\}\}">\psi </figure-callout>}}_{02}+{\psi }_{0\mathrm{from}d\mathrm{at}\mathrm{and}g\mathrm{but}}+{\psi }_{2PRe\mathrm{about}bR}\right)$$

.

Instantaneous value ψ _{add. the difference} (r, t) of the phase of the additional signal of the difference frequency up to a constant phase shift is equal to the difference ψ _{1 add. prin} (r, t) and ψ _{2 add. prin} (r, t) phases of the received additional signals:

$$\begin{array}{l}{\psi }_{d\mathrm{about}P.R\mathrm{but}sn}(r,t)={\psi }_{\mathrm{one}d\mathrm{about}P.PR\mathrm{and}n}(r,t)-{\psi }_{2d\mathrm{about}P.PR\mathrm{and}n}(r,t)=\\ =\left({\omega }_{\mathrm{one}}-{\omega }_2\right)t-\frac{\mathrm{one}}{c}\left({\omega }_{\mathrm{one}d\mathrm{about}P}{r}_2-{\omega }_{2d\mathrm{about}P}{r}_{\mathrm{one}}\right)-{\psi }_{0d\mathrm{about}P},\end{array}$$

where ψ _{0 add} = (ψ ₀₁ -ψ ₀₂ ) + (ψ _1convert -ψ _2convert ) -ψ prev _{. additional} ;

ψ _{prev. add} - an additional phase shift when converting into an additional signal of a difference frequency.

The difference Δψ (r (t)) of the phases of the main and additional signals of the difference frequency at the point of location of the control object is determined by the following expression:

$$\begin{array}{l}\Delta \psi \left(r\left(t\right)\right)={\psi }_{\mathrm{about}\mathrm{from}n.R\mathrm{but}sn}(r,t)-{\psi }_{d\mathrm{about}P.R\mathrm{but}sn}(r,t)\\ =-\frac{\mathrm{one}}{c}[{\omega }_{\mathrm{one}}{r}_{\mathrm{one}}-{\omega }_2{r}_2-\left({\omega }_{\mathrm{one}d\mathrm{about}P}{r}_2-{\omega }_{2d\mathrm{about}P}{r}_{\mathrm{one}}\right)]-{\psi }_{00}=\\ =-\frac{\mathrm{one}}{c}[\left({\omega }_{\mathrm{one}}+{\omega }_{2d\mathrm{about}P}\right)r_{\mathrm{one}}-\left({\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="00000019.png"\; state="\{\{state\}\}">\omega </figure-callout>}}_2+{\omega }_{\mathrm{one}d\mathrm{about}P}\right)r_2]-{\psi }_{00},\end{array}$$

where ψ ₀₀ = (ψ pref.- _main -ψ pre- _add ) + (ψ _1convert -ψ _2convert ).

The phase difference of the main and additional signals of the difference frequency at the point of location of the control object does not depend on the initial phases of the main signals and, therefore, on the corresponding phase instabilities. This significantly (by orders of magnitude) reduces the requirements for the coherence of the main signals.

We show that the lines of equal phase differences of the main and additional signals of the difference frequency are fan-shaped and directed towards the segment connecting the location points of the beacon antennas.

We define the gradient of the function Δψ (r (t)), while taking into account that

; $$grad\left(r_{\mathrm{one}}\right)=r_{\mathrm{one}}^0$$

;

; $$grad\left(r_2\right)={\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="00000019.png"\; state="\{\{state\}\}">r</figure-callout>}}_2^0$$

;

Then

, $$grad\left(\Delta \psi \left(r\left(t\right)\right)\right)=-\frac{\mathrm{one}}{c}D$$

,

Where $$\begin{array}{l}D=\left({\omega }_{\mathrm{one}}+{\omega }_{2d\mathrm{about}P}\right)r_{\mathrm{one}}^0-\left({\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="00000019.png"\; state="\{\{state\}\}">\omega </figure-callout>}}_2+{\omega }_{\mathrm{one}d\mathrm{about}P}\right){\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="00000019.png"\; state="\{\{state\}\}">r</figure-callout>}}_2^0=\\ =\left({\omega }_{\mathrm{one}}+{\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="00000019.png"\; state="\{\{state\}\}">\omega </figure-callout>}}_2+{\omega }_{\mathrm{from}d\mathrm{at}\mathrm{and}g\mathrm{but}}\right)r_{\mathrm{one}}^0-\left({\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="00000019.png"\; state="\{\{state\}\}">\omega </figure-callout>}}_2+{\omega }_{\mathrm{one}}+{\omega }_{\mathrm{from}d\mathrm{at}\mathrm{and}g\mathrm{but}}\right){\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="00000019.png"\; state="\{\{state\}\}">r</figure-callout>}}_{2.}^0\end{array}$$

Thus, the vector D is equal to the difference of two vectors having the same length ( _shift ω ₁ + ω ₂ + ω).

The vector of the phase difference gradient is perpendicular to the line of the phase difference tangent to the line (surface). Thus, the position of the tangent to the line of equal values of the phase difference at the location of the control object is determined by the vector D.

From the diagram in figure 1 it can be seen that the vector D is perpendicular to the bisector of angle β. Therefore, the tangent to the line of equal phases intersects the segment connecting the location points of the beacon antennas. This is true for all positions of the control object and for all positions of the beacon antennas.

Figure 2 shows the lines of equal phase differences for a specific location of the antennas and the trajectory of the control object. Lines of equal phase differences intersect the segment connecting the location points of the beacon antennas. Thus, the task of bringing an object to a given point can be reduced to the problem of moving along a path coinciding with one of the lines of equal phase differences of the main and additional signals of the difference frequency.

As the value of the phase difference on the selected line of equal phases can be used the value of the phase difference at the time of the start of control. This value corresponds to the line L _{0 of} equal phase differences passing through the starting point M ₀ .

Accordingly, at the start of motion control object determines the initial value of the phase difference Δψ _nach basic and additional difference frequency signals, and at subsequent instants determined current values of Δψ (r (t)) of the phase difference of the main and additional difference frequency signals.

If after the start of control the object moves along the line L ₀ , then the deviation of the current values Δψ (r (t)) from the initial value Δψ _nach is zero, which should correspond to a zero error signal.

If, as shown in figure 2, the vector V _{0 of the} speed of the control object at the time of the start of control (or at any other moment) is not directed along the line L ₀ , the object deviates from the line L ₀ , the current values of the phase difference deviate from the initial value, which leads to the formation of an error signal, the sign and value of which are determined by the sign and the magnitude of the deviation from the line L ₀ . In accordance with the error signal, a control signal is generated, as a result of which the control object returns to line L ₀ and moves along it in the “gate” direction between the beacon antennas.

The determination of the phase difference Δψ (r (t)) and its deviations from the initial value Δψ _nach can be carried out in various ways. In particular, as shown in Fig. 4, the phase difference Δψ (r (t)) can be determined in the digital determinant of the phase difference, the value of the phase difference at the time of the start of control Δψ _nach can be recorded in the storage device by the write command, and the phase difference deviation can be determined by summing the current value of the phase difference Δψ (r (t)) and taken with the opposite sign of the initial value Δψ _beg .

In order to ensure a one-to-one correspondence between the deviations of the phase difference and the deviation of the position of the control object from the line L ₀ , an algorithm should be used in the digital determinant of the phase difference, in which the integer number of periods used in the inverse trigonometric function is not “reset”.

In particular, the algorithm can use periodic calculation of the tangent of the phase difference, followed by the calculation of the arc tangent. The result is the main value of the arc tangent, which may differ from the true value of the phase difference Δψ (r (t)) by a multiple of π:

Δψ (r (t)) = _{Δψ principal} + nπ,

where _{Δψ chiefly} is the main value of the arc tangent;

n is an integer.

When determining the initial value of the phase difference, n is assigned any final value. For example, zero.

At each of the subsequent moments, the obtained next main value of the arc tangent is compared with the value at the previous moment. If the increment of the main value of the arc tangent in absolute value is greater than some acceptable value, then this is a sign of the next "reset" of π. In this case, to compensate for the "reset" it is necessary to change the value of n. If the new principal value is less than zero, then n should be increased by one. If the new principal value is greater than zero, then the value of n should be reduced by one.

The error in bringing an object to a point is determined by the distance between the beacons.

Claims (1)

The method of generating error signals when controlling the movement of an object with the aim of outputting it to a given point, which consists in the fact that the control object is irradiated with radio signals, and at the control object the radio signals are received and converted into error signals, characterized in that the first and second main signals of unequal frequencies are generated and the shear frequency signal, the first main signal and the shear frequency signal are converted in the first frequency converter into a first additional signal whose frequency is shifted relative to the frequency of the first about the main signal to the shear frequency, the second main signal and the shear frequency signal are converted in the second frequency converter into a second additional signal whose frequency is shifted relative to the frequency of the second main signal by the shear frequency, the corresponding generated signals are sent to the first and second beacons located near a given point , while the first beacon emits the first primary and second additional signals, the second beacon emits the second primary and first additional signals, n and the control object, the received main signals are converted into the main signal of the differential frequency, the received additional signals are converted into the additional signal of the differential frequency, at the moment of the beginning of the control of the object’s movement, the initial value of the phase difference of the main and additional signals of the difference frequency is determined, at subsequent moments the current values of the phase difference of the main and additional signals of the differential frequency and generate error signals depending on the deviations of the current values differently five phases of the main and additional signals of the difference frequency from the initial value of the phase difference of the main and additional difference frequency signals.

Images