RU2309429C2 - Method of combined radar automatic detection and route tracking, circular observation of air, on ground, over-water targets, local radio communication and near radio navigation of objects and subjects - Google Patents

Abstract

FIELD: radiolocation.

SUBSTANCE: radio pulse sequence is irradiated from several apart-standing positions of specific duration to have specified period of repetition. Groups of radio pulses are received or radiated alternatively during any period of repetition: sync pulses, controls signals, error protection code, data transmission, checking codes to select pause for period of protection interval and radio pulses reflected from target, surface of earth or water and local objects are received during any time period from roll-out of current radio pulse to front of subsequent radio pulse. Reflected radio pulses are stored between periods. Signal of target is detected by comparing amplitude of stored pulses with preset threshold after reflected last probing pulse is received. Two monochromatic pulses are irradiated, which pulses have doubled period of repletion and have highly stable duration and period of repetition. Also radio pulses are radiated which have to be equidistant one to another, which pulses are received after they had been retranslated.

EFFECT: high noise immunity; high precision of detection and identification.

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Description

The invention relates to radar technology and is intended for radar automatic detection and route tracking of a circular view of air, ground and surface targets, local radio communications and short-range radio navigation of objects (subjects)

There is a method of detecting air targets by sharing a reconnaissance and target designation station, a circular view of a target tracking and guidance station, 1C91 2K12 anti-aircraft missile system (KUB) (see Air defense and missile defense volume IX, Encyclopedia XXI. M.: Weapon and Publishing House technology ", 2004, pp. 414-444).

However, a self-propelled reconnaissance and guidance installation provides the task of detecting, automatically tracking a single target and guidance by two separate stations.

A known method of radar detection and measurement of the coordinates of objects (see Radio Electronics Abroad, 1980, No. 17, p. 23), providing for the radiation of the S-band surveillance station (for example, RAT-31S radar, λ = 7-15 cm, used in air traffic control systems and air defense - air defense) of a certain duration and with a given repetition period Tp of a sequence of sounding radio pulses, reception of radio pulses reflected from the target, inter-period accumulation of reflected radio pulses, signal detection s goal and comparison with a predetermined threshold accumulated RF pulse amplitude.

However, the concentration of energy when viewing each direction is insufficient to detect subtle objects that have a small effective scattering surface (EPR), since in a short period (units of seconds) it is necessary to examine the entire area of the circular review of space.

A known method of radar detection and measurement of the coordinates of objects (see patent RU No. 2211458, IPC G 01 S 13/00, from 08.27.03), based on the detection of objects with a circular view of the space (for example, a long-wave radar), measuring their coordinates with transmission tracking data for a short-wave radar and after detection of objects with higher accuracy, the measurement of angular coordinates.

The disadvantage of this invention is the presence of two radar stations of short and long ranges of radiation of electromagnetic waves.

A known method for determining the coordinates of a radiation source (see Theoretical Foundations of Radar. 1970, edited by Ya.D.Shirman, M .: Soviet Radio, pp. 495-497), based on the reception of radio emissions in at least two points with known coordinates , determining the direction of the source of radio emission, due to which calculate the distance to the source.

However, the presence of several points of reception of radio signals, which greatly complicates the system, reduces its reliability and mobility.

There is a method of detecting air targets (see S.I. Petukhov. History of the creation and development of weapons and military equipment of the air defense of the Russian Ground Forces. 1998, part 1, p. 216), which includes a station for detecting round-robin targets and a target tracking station , the azimuthal direction of the antenna line of sight of which coincides with the azimuthal direction of the launcher.

The known method of transmitting the necessary information about an air target to a fighter carrying means of hitting air targets, determining the fact of its being in the antenna radiation pattern (BOTTOM), is implemented in the secondary address radar - command and control station "Rainbow - SPK-75P" (see Aviation Radar systems and equipment, Moscow, Military Parade LLC, calalogue, vol. 5, part 7, pp. 313-333). "Rainbow - SPK-75P" receives this information from three command posts (CP) via a telecode communication line (TKS). The fighter transmits a “receipt” on receipt of data about the air target to the Rainbow - SPK-75 P, which determines the polar coordinates of the fighter, through a return communication channel.

"Rainbow - SPK-75 P" does not perform the functions of detection and route tracking of airborne and, all the more, other targets, but only transmits them to a fighter, i.e. Acts as an active intermediary in the telecode communication line, as well as an active intermediary in determining the polar coordinates of a fighter.

A known method of detecting, identifying nationality and measuring the coordinates of air targets and issuing target designation for an automatic control system (ACS) is implemented in the radar and communications complex (ASRK) "Delta (see. Arms of Russia. Moscow, Military Parade LLC, catalog, v. 5, pp. 218-223, 1996-1997).

The complex consists of two channels, each of which contains a radar and communication point (ASRP), and a data processing and control post (PODU).

Each PODU is approximately 200 km from the corresponding ASRP. The control signals are received from the PODU in the ASRP through the tropospheric communication channel built into it. Accordingly, from the ASRP, data on the detected and followed targets are received in the PODU. The connection between the PODU and the ASRP is carried out in a narrow spatial sector, although the location of the ASRP relative to the PODU is not regulated, except for the distance from the PODU. In this method, there are functions of detection and route tracking of air targets, but the communication and detection and route tracking functions are not combined. In addition, there are no detection and route tracking functions for surface and ground targets, and the size of the communications sector is very far from circular.

The closest in technical essence and the achieved result is a method of radar automatic detection of air targets, local radio communications and short-range radio navigation of objects, implemented in a mobile reconnaissance and control center (PPRU) 9C80M1 (see Air defense and missile defense, 2004, Encyclopedia XXI century, vol. IX, Arms and Technologies Publishing House, pp. 548-549), providing for radiation of a certain duration with a given repetition period T _{p of the} sequence of sounding radio pulses, and during each time interval from the decline of the current radio pulse to the front of the next radio pulse, reflected radio pulses are received, inter-periodical accumulation of reflected radio pulses is made, a target signal is detected, comparing the amplitude of the accumulated pulses with a predetermined threshold, and also providing communications and automated control of military means using data transmission equipment of the type " Chord "with detected aerial objects in place and in motion.

The structure of the control gear includes:

- radar with equipment for state recognition of air targets;

- managing hardware and software complex;

- multichannel data acquisition and transmission equipment;

- means of external and internal communication;

- navigation and topographic location system.

However, the ballistic control system implements autonomously isolated communication and navigation systems with an excessively large arsenal of used technical means, without providing route tracking of the target.

The technical result of the invention is the joint detection and tracking of air, ground and surface targets, transmission and reception with high noise immunity to objects (subjects) from several positions by means of radiation of communication line signals with time division of access (TDMA) of data on their exact relative coordinates in a single time and relative coordinates of geodetic benchmarks, providing on the object (subject) the implementation of binding to geodetic benchmarks with the determination of their coordinates, as well as with possibility of subscribers transmitting and receiving a speech signal (message) and other necessary information.

Technical result of the invention is achieved by a method for the combined radar automatic detection and trass support Omnidirection air, land, surface targets, the local radio communication and near navigation objects and subjects radiate from a plurality of spaced positions of certain duration with a predetermined repetition period T _n sequence of radio pulses in groups of radio pulses alternately emit or receive from objects (subjects) in each repetition period: and, control signals, error protection code, information transfer, verification codes, with a pause allocated for the duration of the guard interval and for each time interval from the fall of the current radio pulse to the front of the subsequent radio pulse, receive radio pulses reflected from the target, the surface of the earth or water and local objects interperiodic accumulation of reflected radio pulses is performed; a target signal is detected by comparing the amplitude of the accumulated pulses with a predetermined threshold. After receiving the reflected last in the sequence of the probe pulse (cyclically), after 5-6 round-robin cycles, two monochromatic radio pulses with a double repetition period (2T _P ) of 6-10 μs duration and 6-8 radio pulses of 2- 3 μs, equidistant from each other by 100-70 μs, which are received after their relay.

Since the radar transmitter power is usually much larger than in conventional communication systems, and the radar antennas have a much higher gain for both transmission and reception, as well as a higher spatial directivity, it is difficult to imagine that there may be jammers capable of create interference, the density of which is comparable with the power density of the radar radiated.

The technical result of obtaining high noise immunity of the short-range navigation system is achieved due to the fact that from three, relatively spaced apart, positions transmit data to interacting objects and subjects, including their relative coordinates.

Information is received via a TDMA digital mobile communication line (time division multiple access), for example, DECT (European Digital Wireless System), with temporary duplex separation of transmission and reception modes (TDD), which ensures communication secrecy and protection against unauthorized access, DTC - 900 etc.

In this case, the subscriber’s radio station works only for reception.

In addition, the jammer is not able to determine in what period of the current time navigation data will be transmitted from each position to a given object (or subject).

The technical result of ensuring high accuracy in determining the coordinates at each of the three positions is due to the fact that the radiation and reception of signals from these positions are performed in a known single current time and when transmitting data to the object (subject), the value of the instant of the current time to which the coordinates were received this object (or subject). In addition, since the stability of the generator at the communication object or transceiver in the subject and some objects cannot be as high as that of the master radar generator in each of the positions, the error and the unambiguous delay value during the propagation of the signal from each of the positions are calculated after certain time intervals to the object (subject) and introduce the necessary amendment, which will provide high accuracy in determining the relative coordinates of the object (subject).

The technical result, which facilitates the mass of the equipment, its compactness and reduced power consumption, is due to the fact that, on the one hand, there is no need to install three transmitters and receiving systems instead of one (radar transmitters and receivers, communications and navigation systems), on the other hand, it makes no sense radar equipment, communications and navigation system all the time under current. Thirdly, it is natural to expect that due to the radar equipment performing the communication functions and accurate navigation, the volume partially or fully occupied by the equipment will be reduced.

Comparison of the proposed solution with well-known technical solutions shows that it has a new set of essential features that allow you to achieve the goal.

The essence of the proposed solution will be clear from the following description and the graphic material attached to it.

Imagine a radar with a circular view, the antenna of which rotates at a certain speed and emits sending radio pulses with a given period.

For clarity, we take the pulse repetition period (T _p ) equal to T _p = 800 μs (F _p = 1.25 kHz).

In a certain first repetition period, starting from time t ₀ = 0, the radar emits alternately groups of radio pulses: 16 synchronization radio pulses, 32-bit control signal, 16-bit error protection code, 80-bit signal modulated in frequency or phase transmission of information or speech and 4 bits of verification.

The duration of the bit radio pulse is 0.4 μs, except for the check bits, the duration of which is 0.3 μs. This is followed by a pause of 2 μs, representing the guard interval. The above emission order of the above signals is for demonstration purposes and is borrowed from the existing DEST standard for digital mobile radio communications (digital European wireless communication (see Yu.A. Gromakov. "Standards and systems for mobile communications". Mobile Tele Systems, Eco-Trends, Moscow, 1997) city, pp. 207-211)). This standard is adapted to this method as one example.

The listed mobile signals are presented in figure 1 and make up a single frame with a total duration of 60.8 μs. The information signal may have modulation in the form of a Gaussian manipulation of the minimum frequency shift.

A set of single frames constitutes communication channels for transmission (16 channels) and communication channels for reception (16 channels), as shown in Fig.2. Thus, the communication line provides a speed of 41 kbit / s transmission of information and 16.4 kbit / s transmission of control signals. The total packet transfer rate is 74 kBit / s.

After the guard interval, a radar sounding radio pulse with a linear frequency modulation (LFM) carrier is emitted.

A probe radio pulse with phase-coded carrier keying, for example, a modulated 63-bit M-sequence, can be used.

A radio pulse with a chirp carrier must have a compression ratio of at least 50 ... 60, firstly, because of the need to ensure the detection range, and secondly, in order to significantly exceed the level of signals reflected from targets compared to previous ones reflected from targets and surface radiated signals of the communication line.

For example, let us choose a duration of a radio pulse of 24 μs and a compression ratio of 60. This means that the duration of a compressed radio pulse is 0.4 μs, and its amplitude will be 60 times the amplitude of an uncompressed pulse of the same duration.

Figure 1 shows that the probe radio pulse is separated from t ₀ , t ₀ + T _p , ... t ₀ + NT _p by 60.8 μs.

The radio pulses reflected from the targets and / or the underlying surface are received by the receiver, in which they perform coordinated filtering, for example, by gating and subsequent narrow-band filtering, which is consistent with the accumulation time. Due to the a priori unknown Doppler shift of the carrier frequency due to the movement of the target, there should be a series of narrow-band filters covering the frequency range relative to the carrier from 0 to F _dmax - the maximum Doppler shift corresponding to the maximum speed of the target. The signal amplitude in each Doppler narrowband filter is compared with a predetermined threshold. Exceeding the threshold means the presence of a target signal. Consequently, the target is detected and its route tracking begins according to the data (angles, range and approach speed) coming from the cycle to the review cycle.

Since narrow-band filtering is currently implemented using the fast Fourier transform (FFT), it is advisable that the number of accumulated radio pulses is equal to 2 ⁿ (in our example, 32).

Since during each repetition period the signals of the above frame of the communication system can be emitted, it is possible to realize single-frequency duplex communication by transmitting sixteen communication channels to 16 subscribers in the first 16 periods of information and receiving information from subscribers through the corresponding 16 channels during the remaining sixteen periods of succession. This means that during the last 16 repetition periods only probing radio pulses emit.

Since the emission of communication signals and sounding pulses occurs during the same period, it becomes necessary to solve the significant weakening of the mutual influence of reflected from the targets and the underlying surface. This is achieved, firstly, by the order of emission of the signals, and secondly, by significantly greater energy of the probe pulse (50 ... 60 times with respect to each emitted pulse of the communication line, which do not accumulate from period to period of repetition), and thirdly, it is possible to radiate communication signals and sounding pulses at various carrier frequencies.

In turn, it can be seen that due to the fact that the signal attenuation level during propagation for radar problems is proportional to the fourth power of the range, of connected tasks to the second power of the range, it is clear that the maximum communication range will be much larger than the target detection range. This means that, for subscribers, the sensitivity of the receivers and the power of the transmitting devices is much reduced, which provides stealth and immunity to communication line interference.

As a result of the foregoing, two variants of situations of the state of functioning of the connected and radar channels may arise, and we assume that the range to the object (subject) is sufficient to provide communication.

The first option: the radar detects an object (subject).

The second option: the radar does not detect the object (subject).

In the first embodiment, data on the azimuth, range and elevation angle of objects (subjects), as well as the position location in geographical coordinates relative to a geodetic reference point, can be transmitted via communication channels from one of the positions. As a result, the subscriber located on the object (subject) can accurately determine their location.

In the second embodiment, from each position, data on its azimuth and elevation angle, as well as a single current time for which these coordinates were determined, will be transmitted through the appropriate communication channels to the object (subject).

As a result, on the object (the subject) can be calculated its location relative to three positions and thereby the absolute position on the ground.

In order to improve the accuracy of calculations, it is necessary that they be carried out at the facility taking into account the same time with the receiving facilities. For this purpose, two radio pulses are emitted cyclically from each position with a period equal to twice (or triple) the value of the period of the probe pulses. Doubling the length of the period ensures that there is no possible ambiguity associated with the fact that the communication range exceeds the detection range.

After that, several narrow radio pulses are emitted in order to clarify the current time at interacting objects (in subjects).

The received radio pulses at the facilities (at the subjects) must be relayed, which allows the positions to determine the errors of the same time at the facilities (at the subjects), and data about them will be transmitted through the appropriate communication channels to the facilities (to the entities). For the purpose of noise immunity, these 2 + 6 ... 8 radio pulses will be emitted at different carrier frequencies, changing according to the pseudo-random law.

Claims (1)

The method of combined radar automatic detection and route tracking during a circular survey of air, ground, surface targets, local radio communications with near radio navigation of objects and subjects, which consists in the fact that several spaced radar stations emit a certain duration with a given repetition period T _{n a} sequence of sounding radio pulses and during each period of time from the decline of the current radio pulse to the front of the subsequent radio pulse is received with by means of the indicated spaced radar stations, the radio pulses reflected from the target, the surface of the earth or water and local objects produce interperiodic accumulation of reflected radio pulses, detect the target signal by comparing the amplitudes of the accumulated radio pulses with a given threshold, characterized in that the groups of radio pulses emit and receive from objects and subjects : synchronization, control signals, error protection code, information transmission signals, verification codes, with a pause allocated for the duration of the protection interval, before radiation in each successive period of the repetition of the probe radio pulse from several spaced radar stations, and after receiving the reflected last in the sequence of the probe radio pulse cyclically after 5-6 round-robin cycles from several spaced radar stations, highly stable in duration and period are also emitted at different carrier frequencies following two monochromatic radio pulse with twice the repetition period T 2 _n, and a duration of 6-10 ms and 6-8 for the sake of pulses with a duration of 2-3 μs equidistant from each other by 100-70 μs, received by several spaced radar stations after they are relayed from objects and subjects, and after the target signal is detected, it is tracked according to the data: angles, range and approach speed, received From cycle to cycle of review.

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