RU44190U1 - NAVIGATION SYSTEM - Google Patents

Abstract

The device relates to radio navigation systems designed to determine the current coordinates by the consumer of information. The purpose of the utility model is the development of a mobile local navigation system that implements the following provisions:

the elimination of errors in determining the coordinates of the information consumer due to the instability of the frequency standards of the reference stations and the information consumer;

the ability to change the pace of the formation of the navigation field;

reduction of geometric factor errors;

achievement of system autonomy and mobility of providing consumers with navigation data, etc.

What is new is the introduction of a reference and three slave stations into the structure of the navigation system, the coordinates of whose stationary points are determined. The equipment of the reference station emits a signal, in the structure of which there is a sign, a synchronizing signal and coordinates. In the reception mode, the slave stations respond only to the sign of the reference station, and in the transmission mode they emit (re-emit) the sign, coordinates, and synchronization signal. The information consumer equipment receives the signals of the reference and slave stations, and as a result of solving the system of equations determines the coordinates of the information consumer. The application of the proposed navigation system will significantly increase the navigation and time support of various consumers, and, in particular, when solving the following problems: providing navigation data to ground consumers (equipment, vehicles, people, etc.), manned air vehicles, unmanned aerial vehicles in limits of direct radio visibility; forming a navigation field for guided weapons in the interests of pointing them at objects whose coordinates are known.

Description

The utility model relates to navigation radio systems designed to determine the current coordinates by the consumer of information.

Long-range navigation radio systems (ranging, quasi-ranging, difference-ranging) are multi-position systems based on a network of reference stations located at points with known coordinates. The essence of the procedure implemented with the rangefinder method is as follows. Reference stations at time points emit navigation signals through which a consumer having only receiving equipment and signal processing devices finds his location. At the same time, he uses his own time standard, with which the time of arrival of the navigation signal from the reference station is measured. Radiation Moments and reception synchronized with the Coordinated Universal Time.

In the event of a timeline discrepancy, the reference station systems and the consumer use the quasi-one-dimensional positioning method.

The quasi-one-dimensional method is implemented in the GLONASS domestic global navigation satellite system and in the American NAVSTAR. At the same time, in addition to coordinates, it is necessary to determine the magnitude of the time difference between the scale of the system of reference stations (artificial Earth satellites) and the consumer scale. The number of equations solved by the consumer’s computing device increases by one compared to the rangefinder method.

Thus, the rangefinding method for determining the location of the consumer of information is based on the fact that at each reference station and on the consumer there are highly stable time standards.

For the quasi-dimensional method, it is only necessary at each reference station to have a highly stable time standard.

In the case when the consumer of information needs to determine only his coordinates and does not need to determine the components of speed, in the GLONASS system (NAVSTAR) the main tasks solved by the consumer’s equipment are [1]:

selection of a working constellation of artificial Earth satellites (AES);

introduction to the synchronism of time tracking systems;

delay time measurement;

highlighting and decoding of an informational message;

calculation of satellite coordinates at the time of navigation measurements;

determination of coordinates and corrections to the shift of time scales;

display of calculated data on the scoreboard.

When performing the above tasks, the coordinates of the consumer can be determined with an interval of at least 5 ... 10 seconds.

The value of such an interval is sufficiently large and unacceptable for solving such important tasks as, for example, the task of guiding guided munitions at unobserved targets, the coordinates of which are known.

It should also be taken into account that during periods of “conflict situations” it is hardly necessary to count on the interference-free effect on the GLONASS system.

In the known differential-range navigation systems (determining the coordinates of the location of the information consumer), phase methods are implemented by using which the required measurement rate can be obtained. The system also contains a reference station and several slaves. Reference and slave stations have reference generators that synchronize the transmitters. In the equipment of the consumer of information, the received signals after amplification are fed to the switch, which operates synchronously with the switching of the reference and slave stations. In the consumer structure there is a reference generator, which together with phase meters provides measurement of the phase difference of the signals from the reference station and from the slave station. According to the phase difference of the signals

the distance difference between them and the information consumer is found from the reference and slave stations, and a position line (surface) is also constructed.

Similarly, based on the phase difference of the signals from the reference station and from another slave station, the distance difference between them and the consumer of information is found and another line (surface) of the position is built.

To determine its coordinates, the information consumer, in addition to the lines (surfaces) of the position, has in the database the coordinates of the reference and slave stations.

The uniqueness of range measurement in phase navigation systems is provided only within the wavelength of the carrier wave. To resolve the ambiguity of measurements, pulse-phase systems are used; their navigation signal is a pack of coherent pulses, the carrier frequency of which serves for accurate, and the envelope - for rough measurement of the difference of ranges in order to eliminate the ambiguity of accurate measurements.

In essence, the technical solution closest to the proposed system is the LORAN-C system [2, p. 213]. In the LORAN-C system, all reference stations operate at a fixed frequency, stabilized using cesium frequency standards. The navigation signal of the leading reference station differs from the signal of the slave stations by the number of pulses in the packet and the phase encoding law, which is used to identify the signal and increase its noise immunity. In the LORAN-C system, to prevent the simultaneous reception by the consumer of information of the signals of different reference stations, their additional delay is carried out. The measuring pulses have a temporary position that coincides with the end of the third period of the carrier oscillations.

A significant influence on the accuracy of determining the coordinates of a consumer is exerted by the stability of frequency standards in the equipment of reference stations and the consumer. For example, when frequencies drift, leading to an error in determining the time difference equal to 15 ms, it will give an error in determining the coordinates of 4.5 m.

The pace of formation of the navigation field in systems of the "LORAN-C" type is constant and cannot be regulated in accordance with the tasks solved by the consumers of information.

The accuracy of differential-range systems depends on the geometric factor. For stationary difference-ranging systems, the geometric factor cannot vary.

The purpose of this utility model is to develop a mobile local navigation system in which the above disadvantages are absent.

A mobile local navigation system will be called one that has the property of emergency deployment on the local part of the earth’s surface and is designed to solve the following problems:

providing navigation data to terrestrial consumers (equipment, vehicles, people, etc.) within direct radio visibility;

providing navigation data for manned air assets, unmanned aerial vehicles;

forming a navigation field for guided weapons in the interests of pointing them at objects whose coordinates are known.

This goal is achieved by forming a positional navigation signal by the equipment of the reference and slave stations of the corresponding structure.

The list of drawings in the drawings:

Figure 1. The mutual arrangement of the reference and slave stations and the consumer of information;

Figure 2. Timing diagram of the formation of moments of radiation and signal reception;

Figure 3. Illustration for the derivation of equations;

Figure 4. The structure of the positional navigation signal;

Figure 5. Structural diagrams of reference stations and consumer equipment of the prototype information;

6. Structural diagrams of the reference, slave stations and equipment of the consumer of information of the claimed navigation system.

The essence of the utility model is as follows. To form a navigation field, three stations are deployed, a reference and two slaves, in

if necessary, determine the coordinates on the plane and four in the case of three-dimensional space.

The approach to the disclosure of the essence of the utility model is identical for both cases, therefore, we will dwell on the case of determining coordinates on the plane (see Fig. 1).

When deploying the reference and slave stations on the ground, their rectangular coordinates x _i , y _i (i = 1, 2, 3) are determined by methods known in topographic surveying. Base station (OC ₁₎ emits a radio signal, which are present in the structure of a sign belonging to OC _1, OC ₁ coordinates and clock impuls.OC ₁ operates only in the radiation mode. The second, third slave stations receive signals only on the basis of its belonging to the first. When this condition is met, BC ₂ (BC ₃ ) emits a signal whose structure, like for OC _1, contains a sign of belonging to BC ₂ (BC ₃ ), the coordinates of BC ₂ (BC ₃ ) and a synchronizing pulse. Thus, at each point of the electromagnetic navigation field there are signs of the reference and slave stations, their coordinates and synchronizing pulses.

We show the sufficiency of the listed data to determine the coordinates of the consumer of information x _p , y _p (see figure 2). The time chart shows:

o ₁ t ₁ - travel time of the synchronizing pulse from OC ₁ to the consumer (range D ₁ );

τ ₁₂ is the transit time by electromagnetic energy of the segment Δd ₁₂ is the distance from OC ₁ to BC ₂ ;

o ₂ t ₂ - the time taken by electromagnetic energy of the segment D ₂ - the distance from the aircraft ₂ to the consumer;

After reception, the information consumer captures the moments of arrival of the signal from OC ₁ -t ₁ and from BC ₂ -t ₂ and calculates the difference t ₁₂ , as well as the product c · t ₁₂ , s is the propagation velocity of electromagnetic energy.

From figure 2 and figure 3 follows the relationship:

Taking into account the above dependences, we obtain an equation of the form (1)

in which x _p , y _p are unknown.

To form the second equation, we use similar connections, but between OC ₁ and BC ₃ . As a result, we obtain the following equation:

As a result of the joint solution of equations (1) and (2), x _p , y _p are calculated. For the three-dimensional case, the system of equations for determining the coordinates of the consumer will have the form (3):

where x ₁ , y ₁ , z ₁ ^ - coordinates of the reference station (OC ₁ );

x _k , y _k , z _k - (k = 2, 3, 4) coordinates of the second, third and fourth slave stations (BC ₂ , BC ₃ , BC ₄ );

x _n , _n , z _n - coordinates of the information consumer;

t ₁₂ , t ₁₃ , t ₁₄ - the time difference between the arrival of the synchronizing signal to the consumer of information from the first and second, third, fourth reference stations, respectively;

s = 3 · 10 ⁸ m / s.

Consider the structure of the positional navigation signal of the reference and slave stations (see figure 4). Based on the proposed idea of building a navigation system, the structure of the navigation signal and the reference and slave stations should have positions in the following time sequence:

- position of the station code;

- position of the clock signal;

- position of station coordinates.

With the arrival of the navigation signal from the reference station to the consumer of information, its coordinates and the temporary position of the synchronizing signal are stored. It should be noted that the equipment of the reference station works only for transmission, there is no reception mode.

The equipment of the slave stations has modes of reception and radiation (transmission). In receive mode, the equipment of the slave stations responds only to the code

reference station. In transmission mode, emits the code and coordinates of the station. The synchronization signal of the slave stations is generated by the synchronization signal of the reference station. The equipment of the consumer of information upon receipt of the signal of the slave stations remembers the temporary position of the synchronizing signal and coordinates.

Figure 5 presents the structural diagram of the reference stations and the consumer of the information of the prototype, figure 6 is a structural diagram of the reference, slave stations and equipment of the consumer of the information of the proposed navigation system.

The structural diagram of the reference station (Fig.6, a) contains: a device for entering the code and coordinates of the station, a master oscillator, a transmitter and an antenna. The device for entering the code and coordinates of the station provides the input and storage of the code and coordinates of the reference station, which, under the action of the signals of the master oscillator, through the modulator, modulate the high-frequency oscillations of the transmitter. The master oscillator generates a period of radiation data of the reference station.

The structural diagram of the slave stations (Fig.6, b) contains: an antenna, a decoupling device, a radio frequency amplifier, a decoder, a device for entering the station code and coordinates, a modulator and a transmitter. The decoder provides the selection of the signal only from the reference station, under the action of which the device entering the code and coordinates of the station, modulator, transmitter form the antenna signal of the slave station emitted by the antenna.

The block diagram of the consumer of information (Fig.6, c) contains an antenna, a radio frequency amplifier, a decoder, a clock, a time difference meter and a storage device. The memory device from the decoder receives the codes (numbers) of the stations and their coordinates, and from the time difference meter, the time difference between the moment the signal arrives from the reference and slave stations.

Bibliography

1. Radio engineering systems: Textbook for universities on special. "Radio engineering". / Yu.P. Grishin, V.P. Ipatov, Yu.M. Kazarinov and others; / Ed. Yu.M. Kazarinova. - M.: Higher School, 1990. - 496 p.

2. Bakulev A.P., Sosnovsky A.A. Radar and radio navigation systems: Textbook for universities. - M.: Radio and Communications, 1994 .-- 296 p.

Claims (1)

A navigation system based on the information and energy interaction of reference and slave stations and the consumer of information and containing an antenna, a transmitter, an antenna, a radio frequency amplifier, a storage device in the consumer equipment, characterized in that in order to eliminate errors in determining the coordinates of the information consumer due to instability of frequency standards of reference stations and the consumer of information, the possibility of changing the pace of the formation of the navigation field, reducing errors geometrical factor, eliminating the need for mandatory entering the coordinates of the reference stations in the consumer equipment, achieving autonomy of the system and the mobility of providing consumers with navigation data, it contains: in the equipment of the reference station - a master oscillator, a device for entering the code and coordinates of the station, a modulator, while the output of the master oscillator connected to the inputs of the transmitter, modulator and input device code and coordinates of the station, the output of which is connected to the second input of the modulator, the output of which one with a second input of the transmitter; in the equipment of the slave stations, an decoupling device, a radio frequency amplifier, a decoder connected in series, a modulator, a code and coordinate input device, and the decoder output is connected to the second input of the decoupling device and to the input of the code and coordinate input device of the station, the output of which is connected to the input a modulator; in the consumer equipment, there is a decoder, the first two outputs of which are connected to the inputs of the time difference meter, the third and fourth outputs are connected to the storage device, the time difference meter, the input of which is connected to the clock generator, and the output to the storage device.