RU2658591C1 - Adaptive radio data transmission line of decameter radio wave band - Google Patents

Abstract

FIELD: radio engineering and communications.

SUBSTANCE: invention relates to radio engineering. Technical result is achieved by means of an adaptive radio data transmission line of decameter radio range containing N reception phased antenna arrays (PAA), first and second analog-to-digital converter, computer, low-noise amplifier, first and second multi-channel synchronous quadrature receivers, first and second information processing channels, control unit, beamformer, radio modem unit, fiber optic communication line, PAA-transmitting output signal generating device, local data transmission system.

EFFECT: technical result consists in providing data transmission of the decameter radio wave band.

4 cl, 10 dwg

Description

The invention relates to the field of radio engineering and can find application in adaptive radio communication systems for transmitting location data in three-dimensional space of a radio emission source (IRI) located on an aircraft (aircraft) (airplane, helicopter, etc.), due to reception and subsequent processing electromagnetic waves generated by this IRI.

The invention is used to solve a technical problem, which consists in transmitting decameter range of radio waves (DKMV) data to determine the coordinates of an aircraft in order to monitor it and control its movement by ground services, as well as for its navigation support. The technical result is achieved by introducing adaptation of the signal processing to changes in the noise environment, reducing information loss during reception and increasing the noise immunity of the considered radio link.

The adaptive radio data line of the decameter range of radio waves is intended to transmit information using the principle of the spatio-temporal method of forming the direction of communication with automatic selection of the optimal direction to the signal source, which is a complex signal-code construction.

A large number of inventions are known that use pseudo-random radio frequency tuning (RF frequency) to transmit information.

There is a method of transmitting information for use in communication systems operating in conditions of uncertain interference, described in [1], in which the increase in noise immunity of a radio line under the influence of unsteady interference is achieved in the presence of long-term heterogeneous quality of individual frequency channels.

There is also a known method of transmitting information according to the patent [2], which considers the method of frequency hopping, involving the use of pseudo-random sequences in order to change the value of the operating frequency generated by the pseudo-random law at pseudo-random times, guaranteed synchronously for both sides of the radio line.

The disadvantage of the above methods is the lack of adaptation of the signal to changes in the jamming environment and the increased energy of the radio links.

On-board radio equipment of the aircraft, when performing tasks, create active electromagnetic fields of artificial origin in the frequency range from 1 MHz to 40 GHz. In addition to active fields, aircraft create their own electromagnetic radiation. This emission spectrum can be used to solve the problem of detecting, direction finding and determining the coordinates of an aircraft.

When constructing a multi-position passive radar, the difference-ranging method is used, based on measuring the difference in the signal path from the target to the receiving antennas of the radar. This method allows you to work with pulsed and continuous signals, including noise and noise-like ones.

The principal features of the method are the synchronous method of receiving signals from a radiating source on spaced phased array antennas (PAR). High accuracy of determining the coordinates of the aircraft is provided due to the correlation signal processing, in which the form of the received signal does not matter. The source coordinates are determined by the difference in the arrival of signals to each of the headlamps, and the difference in the arrival of the signal to one position relative to another is determined from the position of the maximum cross-correlation function of the signals from these positions.

The closest technical solution that meets the requirements of passive detection and direction finding is the device described in the article “One-stage estimation of the location of a radio emission source by a passive system consisting of narrow-base subsystems” (Radio Engineering and Electronics, Volume 49, No. 2, 2004, p. . 156-170) is a prototype.

This system contains N receiving antennas, the first and second analog-to-digital converter (ADC), a computer.

The purpose of the invention is the construction of an adaptive radio data line using the method of spatio-temporal formation of the direction of communication with automatic selection of the optimal direction to the signal source.

The result is achieved by centralized processing of signals obtained as a result of receiving electromagnetic oscillations at points whose placement in space is determined by the optimal grouping of weakly directed antenna elements inside structural units implemented by separate technical means of a distributed radio line.

This goal is achieved by the fact that in a system containing N receiving phased array antennas (PAR), the first and second analog-to-digital converter (ADC), the computer additionally includes a low noise amplifier (LNA), N inputs of which are connected to N receiving PARs, the first and the second multi-channel synchronous quadrature receivers (MSCP), the inputs of which are connected respectively to the first and second outputs of a low-noise amplifier, and the outputs are connected to the first inputs of the first and second analog-to-digital converters, the first and second channels are abotki information, the first inputs of which are connected to outputs of analog-to-digital converters, and the outputs are connected to the calculator; a control controller connected at the input to the calculator, the first output of which is connected to the second input of the first multi-channel synchronous quadrature receiver, to the second input of the first analog-to-digital converter and to the second input of the first information processing channel, and the second output to the second input of the second multi-channel synchronous quadrature a receiver, to the second input of the second analog-to-digital converter and to the second input of the second information processing channel; diagram-forming device (DOW), N inputs of which are connected to N receiving headlights; a block of radio modems, the first input of which is connected to the output of the beam-forming device; fiber optic communication line, the inputs of which are connected to the outputs of the block of radio modems; a device for generating an output signal, the inputs of which are connected to the outputs of the fiber optic communication line; transmitting HEADLIGHT, the inputs of which are connected to the outputs of the output signal generating device; a local data transmission system connected to the output of the calculator, to the second input of the beam-forming device, to the second and third inputs of the block of radio modems; special communication manager software connected by a communication line to a local data network.

Comparison with the prototype shows that the inventive system is characterized by the presence of new blocks and their connections between them. Thus, the claimed system meets the criterion of "novelty."

Comparison of the proposed solution with other technical solutions shows that the listed elements used in the blocks are known, however, their introduction in this connection with the other elements leads to the expansion of the functionality of the system.

This confirms the conformity of the technical solution to the criterion of "significant differences".

In FIG. 1 presents a general diagram of the proposed adaptive radio line decameter range of radio waves, in FIG. 2 shows the structure of a terrestrial adaptive radio link of the decameter range of radio waves, FIG. 3 shows the structure of a narrow base subsystem (UP), in FIG. 4 shows the device of the receiving and transmitting HEADLIGHTS, in FIG. 5 shows the structure of the information processing channel; FIG. 6 shows a block of a radio modem, in FIG. 7 shows the structure of an output signal generating apparatus (UVFS), FIG. 8 shows the structure of a quadrature amplitude-phase modulator; FIG. 9 shows the structure of a Hilbert transducer; FIG. 10 gives an option to build a 16-bit DAC.

The adaptive terrestrial radio link of the decameter range of radio waves includes (Fig. 2):

- narrow-base subsystem (UP) I (Fig. 3) consisting of: antenna-feeder system (AFS) 1-1, low-noise amplifier (LNA) 1-2, multi-channel synchronous quadrature receiver (MSC) 1-3,4; analog-to-digital converter (ADC) 1-5.6; control controller 1-9, calculator 1-10, information processing channel 1-7.8, including (Fig. 5) filters 1-11, detector 1-12, direction finder 1-13, output driver 1-14;

- diagram-forming device (DOU) II;

- block of radio modems III;

- device for the formation of the output signal (UVBC) IV;

- transmitting HEADLIGHT V;

- special software (STR) communication manager VI;

- local data transmission system (SPD) VII;

- fiber optic communication line (FOCL) VIII.

The system operates as follows.

In modern conditions of ensuring effective control of aircraft (LA), an important role is given to radio equipment of the decameter range of radio waves (DKMV), which can operate in difficult jamming conditions and conditions for the propagation of radio waves over long distances.

Practical solutions have been obtained in constructing a low-energy radio data line capable of withstanding narrow-band interference and frequency selective attenuation caused by multipath propagation, time scattering, and eliminating intersymbol interference, in addition, providing radio communication with dynamic signal sources and their high relative radial speed.

The terrestrial adaptive radio data line of the decameter range of radio waves (Fig. 2) has several information channels for the exchange of information, among which there may be dedicated communication channels, redundant VHF communication channels and redundant DKMV communication channels.

Communication channels with aircraft (LA) between the ground adaptive radio transmission line for decameter range of radio waves and aircraft at distances out of direct visibility can be arranged only through DKMV radio facilities operating on the principle of propagation of DKMV radio waves with reflection from the Earth’s ionosphere (Fig. 1). Between the terrestrial radio link and the aircraft, it is possible to organize a data exchange channel in duplex and half duplex mode, in which one-way data transmission and reception is possible.

On board the aircraft, to establish an information transmission channel, the KB Communication Terminal (TS-KV) is installed, which is built on the principle of terminal equipment for an on-board adaptive radio data transmission line.

The adaptive radio link (AR) performs frequency range control or control of the designated aircraft communication frequencies when performing a flight mission.

During the output of the onboard radio means to the transmission, direction finding of this transmitter takes place and the AR determines its angular characteristics α, β relative to the location point of the phased array (Fig. 4) of the direction finding device (Fig. 5) from the composition of the AR.

Since the transmitter is located on board the aircraft, the coordinates of the radiation source are also the coordinates of this aircraft.

The values of the bearing and elevation angle (α, β) are attached to the timeline and, together with the measurements obtained, are recorded in the primary database goal form as part of special software (STR) of the communication manager of the VI AR.

After the formation of a complete control frame of the target forms, they are transferred via the internal local network to the special software of the secondary database.

A secondary database is intended for storing information on goal forms.

Based on information from secondary databases, special software solves the problem of determining the coordinates of all controlled aircraft.

The range coordinate can be determined or refined by the calculation method according to the range calculation algorithm using the height of the ionospheric layer, the triangulation method and the differential-ranging method using the refinement corrections of the first two methods.

The information of the secondary database on the AR has access to the STR of the communication manager VI (Fig. 2) for constructing dynamic trajectories of aircraft movement in space. Dynamic information can be visualized on the monitor of the operator’s technological workplace or on a special informational demonstrator.

Algorithms for the functioning of AR

The initial state of the equipment of the AR is the standby mode, in which the equipment located at stationary objects is in the off state.

PAR equipment for reception and transmission, which is removed from the control objects at different distances, is under telemetry control and technical protection of special means of the Republic of Azerbaijan from unauthorized access and vandalism.

To ensure constant monitoring of the current state of the PAR, technical security equipment is constantly included in operation and is located in the quick response or physical security zone.

Transfer of AR equipment from the initial state (standby mode) to the operating state is performed after supplying voltage to the equipment.

In this case, the inclusion of the PAR light equipment for transmission, which is carried out up to several kilometers from the location of the main equipment of the AR, is controlled via telemetry channels.

Through these channels, the information on the temperature state of the power amplifier module (UM 1-64) (Fig. 7) is received in the STR of the communication manager VI (Fig. 2) and, when it deviates from the set values from the technical norm, the heating or cooling thermal switching devices are turned on flow amplifier (radiator UM).

After completion of the cycle of internal self-monitoring of the equipment of the AR and obtaining a positive result, the operating modes of the AR are initialized according to the saved training parameters of the previous sessions of the AR.

When the equipment of the AR is turned on for the first time, a multi-phase semi-automatic adjustment of the equipment and its adjustment to the mode of continuous automatic operation occurs.

The algorithm for establishing communication over service channels provides for the phase of searching for optimal vertical angles of arrival of the radio wave at the receiving headlamp.

To do this, one of the AR channels is transferred to the test signal (TS) transmission mode according to the known time diagram and the correspondent is called for communication to check the parameters of the communication channel at the calling frequency, which is set by the calculation method or by the allowed allowed communication frequencies.

The AR equipment measures the signal-to-noise ratio in the configured communication channels and provides these values to the STR of the communication manager, where the accumulation of measurement information takes place to adopt the optimal communication mode.

For spatial control of the virtual center of the radiation pattern, the narrow-band direction finding device 1-13 (Fig. 4) constantly monitors the angular parameters of the source of the received signal and generates mismatch signals in azimuth and elevation, which are received through the local SPD VII in the STR of the communication manager VI.

Open source software of communication manager VI controls the equipment of beam forming by the transmitting side of the AR in such a way that optimal angular values are applied in real time.

In addition, the STR of the communication manager VI performs tuning of the technical equipment to the designated communication frequencies of all communication devices of the AR and provides for accompaniment to the narrow-band direction finder 1-13 (Fig. 5) the frequency values for monitoring, tracking and a list of allowed and spare communication frequencies with their possible operational replacement in the designated range of technical equipment.

The scheme for constructing digital information exchange provides for the possibility of constant reservation of data transmission channels to ensure uninterrupted operation of the AR.

The radio modem and linear high-frequency equipment of the communication channel are controlled from the STR of the communication manager VI.

Due to the principle of building an exchange in the network, each of the 4 radio modems constantly listens to the direction of communication and expects a ringing signal from the calling party.

After receiving a ringing signal, the radio modem automatically generates a digital communication channel in a given direction for transmitting information to the communication manager or to the designated port for receiving information in the local computer data network.

The interaction and data transfer between the radio modem and the local network is carried out via the TCP / IP protocol in the Ethernet network.

In addition to digital data transmission channels on radio modems, an additional data transmission channel was introduced into the equipment, which provides the communication manager VI with information on the status of communication channels and the transmission medium of radio signals based on the operation of a special mode of the radio modem - measuring the frequency characteristics of the radio channel.

This mode allows you to assess the state of the decameter range of radio waves with an estimate of the amplitude-frequency and phase-frequency characteristics of the channel and energy characteristics in the form of a signal-to-noise ratio in the working band of communication frequencies at the frequencies of the wave schedule issued for the operation of the radio line.

For the case of operational technical increase in the capacity of a radio link in a certain direction of communication, an additional backup channel of a digital radio link in the VHF band is intended, which can also be used for communicating via an additional radio direction with similar equipment and the structure of the signal-code structure of a service digital radio line.

Information digital streams of the secondary database are converted into output streams of data visualizing the processes of work of the equipment of the AR.

The AR control module allows you to generate a digital trajectory of coordinate samples in the form of an interactive display of the flight path of the aircraft.

When constructing an AR, the presence of interfering signals to the receiving headlamp as part of a narrow-base subsystem I from the transmitting headlamp V (Fig. 2) is possible, which will reduce the minimum level of the received radio signal at the receiving point and significantly affect the electromagnetic environment in the installation area of the transmitting headlamp.

To eliminate the mutual influence of radio, it is advisable to ensure the separation of the receiving and transmitting headlamps at an optimal distance.

The magnitude of this distance significantly affects the length of the radio cable from the installation site of the synthesizer of the working signal and the power amplifier under the antenna element of the transmitting headlight V.

A solution is proposed for performing fixed spacing on optical channels for transmitting digital information at large distances, which will allow one to have freedom of choice of solutions and the ability to use the existing infrastructure of optical communication lines.

The essence of the solution is to transfer the spectrum of the working signals of the block of radio modems III (Fig. 2, 6) to the frequencies of the optical range and transport it over the optical channel over long distances, followed by bringing the packed information about the working signal, the amplitude and phase of the partial channel of forming the summing radiation power into a given direction of space and transmission of control signals to the carrier frequency formers with telemetric monitoring of the state of the power amplifier. The group formation of a signal for transmission is carried out in digital form from 8 synthesizers of the carrier frequency of the communication with the subsequent transfer of the group spectrum to the analog form for amplification in power.

To exclude the temperature and current dependence of the transient response of the active elements of power amplifiers (UM 1-64) (Fig. 7), a carrier oscillation phase control circuit is introduced into the shaper structure to take it into account when forming the formation law of the transmitting headlamp V.

The block of radio modems III has at its output a working signal of the modem modulator in the form of digital samples.

The transmission path of the radio link is a digital device based on the principles of digital signal processing with subsequent filtering and power amplification in a terminal power amplifier loaded with the complex resistance of an antenna emitter.

The formation of digital samples of the transmitted signal occurs in the modem in the low frequency band with the following parameters:

• Sampling frequency - 64 kHz;

• Bit depth - 16 bits.

The generated samples are packed into the frame structure of the digital stream E1 (G.704 standard: without Multiframe, without signaling KI16, without CRC4), starting with KI1, which follows the zero KI of frame synchronization.

The digital stream speed E1 is 2048 kbit / s, including KIO.

The useful information transfer rate in the stream (without KIO) is: 2048-64 = 1984 kbit / s.

The speed of the resulting digital sample stream of the transmitted signal is: 16 bit * 64 kHz = 1024 kbit / s, for which it is necessary to take: 1024/64 = 16 channel intervals in the signal structure.

The proposed layout of samples in the E1 frame structure of 8 samples in one frame in the following order:

The generated digital stream is transmitted to port E1 in accordance with the physical parameters of the G.703 signal and delivered to the optical multiplexer via a CAT 5 twisted-pair cable (Fig. 6).

In the multiplexer, a G.703 physical signal is decoded, a data bit sequence is generated, and E1 frame synchronization is performed.

The extracted samples go to the Hilbert transducer (Fig. 9), at the output of which a quadrature representation of the signal samples is formed.

Quadrature samples of the transmitted signal are sent to the multiplexer, where they are packed into some frame structure of a high-speed digital stream together with data from the Ethernet port, and then transferred to the fiber-optic cable to the response device.

The transmission speed of information in the optical fiber is 1250 Mb / s, including channel coding.

Thus, information about the signal and control of the output synthesizer is transmitted through a single optical channel.

The second optical channel is necessary for high-quality transmission of the reference frequency signal.

The Ethernet port is designed to transmit service, control information and telemetry of the power amplifier, as well as packets containing samples of the transmitted signal.

On the far side, the received digital stream is being processed. From it, data from the transmission channels of the signal samples and the data of the Ethernet channel are extracted (demultiplexed).

Ethernet data is analyzed for control information for synthesizers.

Control information is interpreted into appropriate commands and structures.

Ethernet packets that do not contain control information are sent to the output Ethernet port, to which external devices can be connected, or the removal of a local network at a remote site is organized.

After demultiplexing, the formation of a digital stream begins towards synthesizers (Fig. 7).

This digital stream has a fixed length, a personnel structure, is built on the principle of temporary separation of channels and contains samples for each channel, as well as control information for synthesizers in the form of formed commands and structures.

The digital stream enters the optical transceivers, then through a multi-channel optical splitter (splitter 1, 2) (Fig. 7) and through optical cables of fixed length it is transmitted to the synthesizer modules 1-64 located at the antenna elements that make up the transmitting PAR V (Fig. 7). Similarly, the reference frequency signal is transmitted through optical transceivers to a multi-channel optical splitter and transmitted through 16 optical cables to the synthesizer modules.

The optical cable includes 2 or 4 optical fibers, depending on the choice. This means that not two optical cables are pulled to the synthesizer, but one, but the synthesizer is connected by two optical fibers.

The synthesizer is a digital signal processing module in which the working frequency signals are generated and the spectrum of the low-frequency signal is transferred quadrature to the carrier frequency of the communication.

The computing power of the synthesizer allows you to simultaneously generate up to 8 operating frequencies.

The samples coming through the optical channel are the quadrature components of the signal with a sampling frequency of 64 kHz and a resolution of 16 bits.

These samples form the low-frequency spectrum of the working signal for each of the carrier frequencies of the communication.

Received signal samples can be interpolated, for example, with a factor of 1280 up to a sampling frequency of 81.92 MHz.

At the indicated frequency, quadrature readings of the working frequency (carrier) signals are formed by the direct synthesis method (DDS).

When generating working frequency signals, a phase shift (in other words, an initial phase) and an amplitude level can be added.

The quadrature samples of the low-frequency signal are multiplied by the corresponding quadrature components of the working frequency signal, and then summed.

These operations are performed for each of the eight operating frequencies and their corresponding bass signals.

The samples obtained at the outputs of the adders are fed to the adder and thus form a group spectrum containing eight communication radio signals.

The samples of the resulting signal are sent to the 16-bit DAC, after which the analog signal is filtered from the output and fed to the PA, and from the amplifier output the amplified signal is fed to the transmitting antenna.

An example of a construction variant is shown in FIG. 9.

To control the correct operation of power amplifiers (UM 1-64) (Fig. 7), the transmitting headlamp V has two parameters necessary for monitoring: the level of the incident and reflected waves and the temperature of heat dissipation of the dissipated power.

To control and promptly respond to these parameters, two low-speed ADCs are included in the synthesizer module, the readings from which can be transmitted via the telemetry channel to the control center together with digital temperature signals.

Thus, in this solution, uncontrolled processes of automatic feedback adjustments in solutions with auto-limiting the radiation power of powerful amplifiers are eliminated and a controlled operation by the power level becomes possible.

Feedback limited power solutions of autonomous amplifiers under the antenna can lead to a significant uncontrolled limitation of the power of the PA during their operation as a headlamp, since any change in reactive power in the area where the antenna elements are located will automatically reduce the power to an uncontrolled level and the amplitude-phase opening The headlamp will be uncontrollable.

The composition of the device for generating the output signal IV (Fig. 7) includes a control and measuring receiver (KIP) for estimating the phase value in the established transmission channel.

The analog signal from the DAC output passes through analog switching and amplification circuits, which have various constant transmission media.

Constant propagation media introduce a certain amount of signal delay at the emitter output. If the magnitude of this delay is unknown, then the initial phase of the emitted signal will be randomly changed, which will lead to a change in the given direction of energy addition in space.

To eliminate the influence and clarify the real value of the phase of the signal in the transmitting antenna path of the antenna elements, an instrumentation has been introduced into the circuit, which makes it possible to measure the phase of the emitted signal with high accuracy by any channel of the HEADLIGHT and transmit this value through the control channels to the communication manager.

The measurement process has a high degree of accuracy due to the use of a high-precision reference generator in the reference signal generation circuit and the moment the phase meter is started.

The moment of the beginning of the synthesis process of the output signal in the synthesizer module and the start of measurements in the instrumentation are synchronized by a special command from the communication manager and spaced apart in the operating time of each transmission channel.

The phase values are transmitted to the STR of the communication manager VI (Fig. 2), where they are taken into account when calculating a given direction as corrections from the operational values of the measured delays.

The adaptive radio data line of the decameter range of radio waves is intended to transmit information using the principle of the spatio-temporal method of forming the direction of communication with automatic selection of the optimal direction to the signal source, which is a complex signal-code construction.

Principle of operation

The control program of the STR of the communication manager VI initializes the equipment included in the AR to the specified initial state.

The direction finding device of radio signals (PUR) I-13 (Fig. 5) is configured to view the specified frequency range for searching and detecting the signal of the communication frequency and calculating the direction of arrival of the radio wave in azimuth and elevation. The DSP works on the basis of a one-stage direction finding algorithm for the radiation source (IRI), which allows you to calculate the angular parameters of the IRI. To ensure the functioning of the direction finding algorithm, the DSP is connected to the receiving PAR (I-1) (Fig. 3) of a given configuration.

To the receiving headlamp I-1 as part of a narrow-base subsystem I (output 1) a diagram-forming device (DOU) II (input 1) is connected (Fig. 2), which provides amplitude-phase addition of signals at the output from a given spatial direction. The output signal of the receiving headlamp is fed to the block of the radio modem III to perform frequency selection of the spectrum of the working signal, its amplification and ensure the operation of the demodulator channel of the radio modem block.

The law of addition formation in DOW II is set from the STR of the communication manager VI through the local data transmission network (SPD) when IRI bearings are detected in IUR 13. The value of the current bearing in Iran is transmitted to DOW II through SPD in real time.

The block of radio modems (BRM) III provides the conversion of input information from the STR of the communication manager VI into a complex signal for transmission through the communication channel in the modulator of the radio modem and demodulation of the complex signal into the information stream that is received in SPD VII.

BRM generates a signal towards the device for generating an output signal (UVBC) IV (Fig. 2).

Narrowband subsystem (UP) I (Fig. 3)

A radio emission source (IRI) located on the aircraft generates an electromagnetic signal, for the description of which a model of a Gaussian radio signal is used:

where K is the number of components taken into account,

f ₀ - carrier frequency,

f _k are the frequencies of the considered components in the spectrum of the complex envelope,

a _k and b _k are coefficients that are Gaussian mutually independent random variables.

Such a signal corresponds to the case of a stochastic model, the application of which ensures the operation of the system in conditions of the least available a priori information.

The narrow-base subsystem I is a technically unified receiving station that implements multichannel reception at individual points of reception (TP), the placement of which in the structure of the antenna system UP I satisfies two conditions:

1. The distance between the TP of the same UE is much less than the distance between the UE and IRI. This condition provides a flat wave front.

2. The distance between the TPs of the same UE does not exceed half the wavelength λ0 = c / f ₀ corresponding to the carrier or center frequency of the received radio signal f ₀ , and c means the speed of propagation of the signal from the IRI to UE equal to the speed of light.

UE I consists of an antenna-feeder system (AFS) I-1, a low-noise amplifier unit (LNA) I-2, a multi-channel synchronous quadrature receiver (MSC) I-3.4, a block of analog-to-digital converters (ADCs) I-5, 6, the first and second channels of information processing I-7.8, the control controller I-9 and the computer I-10 connected by a communication line (output 2) to the local SPD VII (Fig. 2). The LNA block I-2 pre-amplifies the signals before it is transmitted to the inputs of the I-3 ICP. The MSKP, ADC blocks are program-controlled, the operation mode of which is set by the control signals of the I-10 computer.

When receiving electromagnetic waves are converted into an analog electrical radio signal, which is fed to the input of the LNA I-2, the output of which the radio signal is fed to the inputs MSC I-3,4. As a result of synchronous detection, an analog video signal is generated at the outputs of the MSCP, which is supplied in the form of pairs of quadrature to the inputs of the I-5.6 ADC, the output of which is a digital signal in the form of samples.

Distinctive characteristics of the MSCP are the central frequency, tunable over a wide range: from 20 MHz to 3 GHz, and a wide frequency band of the demodulated signal, amounting to 60 MHz, which defines the signal as broadband in the upper part of the center frequency range and as ultrawideband in its lower part . To achieve the required reception quality, independent digital gain control of each channel is carried out in 0.5 dB steps, and the synchronization of each channel pair of the quadrature receiver should provide a phase difference in the accuracy of the quadrature of no more than 2 degrees in absolute value. To obtain a technical result, a multi-channel 16-bit multi-channel ADC with a tunable sampling frequency is used, with a maximum frequency of 100 MHz, which, taking into account the protective intervals, is consistent with the maximum band of the received radio signal.

The synchronization of sampling in various ADC channels should ensure the mismatch of time instances of not more than 0.05 of the used sampling period.

The I-10 calculator is implemented on the basis of a high-performance multiprocessor workstation equipped with at least two multi-core universal Intel Xeon processors with an operating frequency of at least 1.8 GHz and a random access memory (RAM) with a capacity of at least 8 GB. The computer I-10 in the structure performs the functions of controlling the operation of the unitary enterprise (I) by setting the functional modes of individual blocks. In addition, the I-10 calculator performs preliminary digital processing of the received signals, as well as their compression before transmission over the communication line.

The antenna system UP (I) is located on a vertical mast (Fig. 4), the height of which is from 1.5 to 18 m. In the upper part of the mast, over a section of length L, one to nine ring antenna sublattices (CAP) are placed. The minimum distance between planar CADs is 0.5 m, which is due to the technological features of the mount, and the maximum is limited by the length of the working section of the mast L.

The structural organization of the distributed receiving system of the AR allows you to create at the reception the necessary spatial distribution of the electromagnetic field of the signal emitted by the IRI.

Let the IRI be located at a point in space whose coordinates are given by the vector r = (X, Y, Z) ^T. Then the signal received by the m-th TP, consisting in the structure of the UE, is the sum of the delayed and weighted useful signal, and the additive noise:

where a _n is the amplitude of the signal at the inputs of the TP UP;

- время прохождения сигнала от ИРИ до условного фазового центра (УФЦ) УП;

- the signal transit time from the IRI to the conditional phase center (UFC) UP;

- координаты УФЦ УП;

- coordinates of the UFTS UP;

χ _n is the error of the signal binding in time;

- время прохождения сигнала от УФЦ до ТП (от ТП до УФЦ, если

);

- signal transit time from UFTS to TP (from TP to UFTS, if

);

- координаты m-й ТП УП;

- coordinates of the m-th TP UP;

α _n , β _n - azimuth and elevation angle of the beam directed from UE to IRI;

c - signal propagation speed.

A distinctive condition for the effective use of this model is that the signal observation time at each position should be chosen much longer than the signal and noise correlation times. Digital samples of all received signals are transmitted via high-speed communication lines to the local SPD VII. Digital signals received by individual TPs are considered together and form a multidimensional digital signal.

Coordinates are estimated using a combined goniometric and differential-ranging method of estimation, in which the entire distributed system is considered as a combined passive system (CPS), combining the common features of a wide-base passive system (WBPS) and a passive system. The method for evaluating such a system is based on a method for calculating an estimate of the difference in the arrival of signals based on the correlation reception using the maximum likelihood method, which is presented in two papers for two reception points [3].

The angular coordinates of the aircraft in azimuth and elevation relative to the point of the center of mass of the carrier are determined by the phase-difference direction finder.

The range to the aircraft is determined by computational methods according to known bearings and the law of displacement of the center of mass in a relative coordinate system.

Functionally, the device consists of an I-13 direction finder with a digital I-1 headlamp, an I-12 detector of time-frequency characteristics of targets (a classifier of targets), output shapers I-14 of target coordinate matrices and I-9.10 calculators in which extrapolation algorithms operate aircraft trajectories, device control algorithms and network data exchange and control algorithms from the radio complex.

The I-13 direction finder with the I-1 digital phased array consists of a fixed antenna array (receiving antennas 20 ... 18000 MHz) located at a spatially separated reception point.

Each of the antennas is connected to the input of the LNA I-2, which provides coordination of the impedances of the antenna element and the connecting cable. Each LNA I-2 output is connected to its receiving path, which is formed by one of the channels of the multi-channel synchronous quadrature receiver (MSC) I-3.4 and analog-to-digital converter (ADC) I-5.6. Thus, an individual digital channel of signal samples from one lattice element is formed.

The I-5.6 signal ADC simultaneously samples a signal across multiple channels. The size of this set is determined by the number of elements of the antenna array I-1. For example, depending on the accuracy requirements for determining the coordinates, you can select 16, 26 or 32 channels. So, for a lattice of 16 elements, the potential accuracy of the device is about 6 arc minutes. As the number of elements increases, accuracy increases.

Coherent signal processing is performed in filters I-11, detector I-12 and direction finder I-13 of the information processing channel I-7.8 (Fig. 5).

Due to the need to ensure the stability of the amplitude-frequency characteristics (AFC) of the direction-finding path, it provides measures for measuring the AFC before taking signal samples in the operating frequency band. Frequency response of the frequency response is associated with the stability of the electrical parameters of the channel and is controlled by the control algorithm of reference (known signal sources) during operation from the I-9 controller.

The I-13 direction finder provides the determination of the angular coordinates of the aircraft (sources of radio emission - IRI) from the phase portrait of the incoming signal. The direction finder determines the angles of arrival of signals to the antenna array from different directions on the same frequency and frequency band. The number of directions is set by the required accuracy of determining the angular coordinates. For an accuracy of 6 minutes, the instantaneous matrix of angles has a dimension of 3600 elements. The time it takes to obtain the bearing (the quantum of time for solving the problem) depends on the speed of the I-10 computer.

Information processing is carried out in the computer I-10.

The matrix (azimuth-elevation angle) is preliminarily filled in the frequency range, which is incomplete, without the range coordinate, which is obtained by the calculation method according to the trigonometric equations of aircraft flight. This coordinate is calculated and it complements the IRI coordinate base to a logical level.

Work dynamics

The multichannel synchronous quadrature receiver (MSC) I-3.4 operates in the direction finding mode of an aircraft at the same frequency with one of the available bands.

The signals from the output of the I-10 calculator are digitally received for processing and issued through the local SPD VII to the STR of the communication manager VI (Fig. 2).

With a certain pace of restructuring MSCP I-3.4 over a range, the IRI is monitored (located) and their coordinates are automatically determined, with reference to the time of detection.

Time binding is performed for the differential-range measuring method for updating coordinates and solving special algorithms for the synthesis of space-time separation.

Thus, the considered system of passive detection of radio sources increases the accuracy of determining the coordinates of the aircraft.

Reception Headlight I-1

Phased array antenna consists of several mutually coherent antenna elements with antenna amplifiers for placement on the mast.

Each mast is installed on the ground at random at a given distance between each other.

One antenna element (AE) has two identical horizontal vibrators, each of which is mutually perpendicular to each other and oriented in the lattice along the geographical meridian and latitude.

Antenna elements have a shortened appearance and their own signal amplifier (US) with a high dynamic voltage range. The DC performs matching of the AE with the wave resistance of the power radio cable and through it the power is supplied from an external voltage source.

The US output is connected to a signal division device (splitter), to which conjugated consumers are connected — a direction finder of radio signals and diagram-forming devices.

Radio direction finder (PR)

The direction finder of radio signals (Fig. 5) performs the function of detecting and determining the direction of arrival of a signal from a radio emission source (IRI). PR works on the principle of a one-stage measurement of the angular coordinates of the IRI.

To solve this problem, the equipment includes special devices for analog and digital conversion of the radio signal and a special computer I-10, which works according to the algorithm of one-stage determination of angular directions in IRI. The values of the angular coordinates are transferred to the STR of the communication manager VI for processing. PR management is performed from the open source communication manager VI via a local data exchange network. PR sets the frequency range of observation over which automatic scanning and search of IRI is performed with the determination of its angular coordinates.

Diagram-forming device (DOW) II (Fig. 2)

The diagram-forming device is made on the basis of lumped components for controlling the phase delays of the radio signal as it passes through the internal processing channels.

The principle of operation of the DOW is based on the possibility of separately controlling the amplitudes and phases of the signals of each element of the antenna system with their subsequent summation to create an amplitude-phase distribution corresponding to a given radiation pattern of the antenna array.

The main element of the DOW is a quadrature amplitude-phase modulator, the block diagram of which is shown in FIG. 8.

The input signal goes to the quadrature phase shifter, where it splits into two orthogonal components. Each quadrature component with the help of two antiphase phase shifters 0 ° -180 ° and keys are additionally “turned” into the desired quadrant. Tunable attenuators produce the formation of amplitudes of the orthogonal components, allowing you to change the amplitude and phase of the signal within a given quadrant on the output adder.

The principle of operation of such a modulator in phase mode can be described by the following formula:

а в косинусном канале – по закону

В этом случае амплитуда выходного сигнала будет постоянной и равна амплитуде входного сигнала.In accordance with this formula, to rotate the output signal by an angle ϕ in the sine channel, it is necessary to adjust the amplitude according to the law

and in the cosine channel - by law

In this case, the amplitude of the output signal will be constant and equal to the amplitude of the input signal.

In the general case, when changing both the phase and the amplitude of the output signal, the original formula is converted to the following form

а в косинусном канале - по закону

In this case, in the sine channel, the amplitude is adjusted according to the Ubx law "

and in the cosine channel - by law

The management of the DOW is carried out from the STR of the communication manager VI. The calculated coefficients are sent to the DOW to ensure coherent addition from a given direction at the output of the DOW.

Block of radio modems (BRM) III

BRM III is designed for preliminary analogue selection of the radio signal, amplification and transfer of the signal spectrum to intermediate frequencies with filtering and its conversion to digital form, followed by digital processing of the signal-code structure (CCM) of the working signal of the radio modem in the modem demodulator.

The working signal of the modem modulator after encoding and generating the output signal-code structure is converted into a digital form of samples of the spectrum of the signal at zero frequency and transmitted through the optical channel to the device for generating the output signal (UVBC) IV (Fig. 2).

Simultaneously with the digital signals of the CCM samples, a signal of a highly stable reference frequency from the BRM III reference generator is transmitted through the optical channel to the UVVS IV side.

BRM III can receive and generate several working signals, which are converted into a serial form for transfer at high speeds to UVVS IV via an optical cable.

Signals from the receiving headlamp I-1 through the DOU II can be received in the BRM III on several reception channels.

Each of the receiving channels consists of an active short-wave preselector (APCW), in which preliminary analogue selection of the radio signal, its amplification, and transfer of the signal spectrum to intermediate frequencies with filtering are performed.

The output signal of the APCW is fed to its channel of the MSVM-138-0 modem demodulator (MSVM-138 - Special Modem Calculator Module - 138 (based on the OMAR processor - 138, dsp & arm 138 of the Ti firm series), 0 - version) (Fig. 6), where the signal is converted to digital form and its subsequent processing.

From the MSVM-138-0 module towards the multiplexer, the modem output signal is generated in digital form in the form of packets from each modem.

In the multiplexer, a packet of information about the direction of transmission in the form of calculated phase values for the signal at the carrier frequency is added to each packet. In addition, a package of control commands of UVFS IV is added to the optical channel.

The device for the formation of the output signal (UVBC) IV (Fig. 2, 7)

The device for generating the output signal performs multi-channel and multi-frequency shaping of the spectrum of the working signals at zero frequency and at a communication frequency. Such a conversion is performed for the spatial addition of the energy of power amplifiers from the transmitting elements of the PAR V in a given direction.

The input demultiplexer and the UVVS IV control unit receives the digital signal stream from the optical cable, parses the packets and sends them to the processing channels, where the stream is converted to the communication channel samples from the radio modem number and communication direction parameters (carrier signal phase, carrier frequency value and its amplitude )

Each communication direction forms its own sample stream of the modem modulator for several synthesizers according to the number of dimensions of VAR V, where each synthesizer sets the initial phase of the carrier frequency of the communication in digital form.

The output stream of all communication directions, consisting of samples of carrier frequencies, is summed up at the input of the digital-to-analog converter of the antenna element (DAC AE).

A complex signal from the output of the DAC through the filter and power amplifier is fed to the antenna element of the PARA V.

In the synthesizer module, the signal-code structure (CCM) of the working signal of the modem modulator is transferred to the carrier frequency, which is set for one of the communication directions.

Transmitting HEADLIGHT V

The transmitting PAR V (Fig. 4) consists of antenna elements located at fixed points in space, to which a radio signal from the output of broadband power amplifiers is supplied.

The installation coordinates of the antenna element are selected based on the required radiation area of the HEADLIGHT V.

Local Area Network (DDS) VII

Local SPD provides transport of control commands between paired devices for transmission in predetermined communication directions.

Special communications manager software (STR) VI The STR of communications manager VI consists of a subset of control and processing programs for the intended purpose of the radio link.

Thus, the considered adaptive radio data line of the decameter range of radio waves provides its hidden operation due to the principle of spatio-temporal formation of the direction of communication with automatic selection of the optimal direction to the signal source with the formation of a digital trajectory of reference coordinates of the flight path of the aircraft due to passive detection of aircraft radio emission sources.

Information sources

1. RF patent for the invention No. 2185029 "Radio line with pseudo-random tuning of the operating frequency", Odoevsky S. M., Eryshov V. G., 2001.

2. RF application for invention No. 2001102653 "Method and device for pseudo-random tuning of the operating frequency", Postnikov VA, Shubenkin VV, 2001.

3. Knapp S.N., Carter G.C. The Generalized Correlation Method for Estimation of Time Delay // IEEE Transactions on Acoustic, Speech and Signal Processing, 1976, vol. 24, no. 4, p. 320-327.

Claims (4)

1. Adaptive radio data line decameter range of radio waves containing N receiving phased array antennas (PAR), the first and second analog-to-digital Converter, a computer, characterized in that it additionally introduced a low noise amplifier, N inputs of which are connected to N receiving PAR, the first and second multi-channel synchronous quadrature receivers, the inputs of which are connected respectively to the first and second outputs of a low-noise amplifier, and the outputs are connected to the first inputs of the first and second analog-to-digital pre verters, the first and second information processing channels, the first inputs of which are connected to outputs of analog-to-digital converters, and the outputs are connected to the calculator; a control controller connected at the input to the calculator, the first output of which is connected to the second input of the first multi-channel synchronous quadrature receiver, to the second input of the first analog-to-digital converter and to the second input of the first information processing channel, and the second output to the second input of the second multi-channel synchronous quadrature a receiver, to the second input of the second analog-to-digital converter and to the second input of the second information processing channel; chart-forming device, N inputs of which are connected to N receiving headlights; a block of radio modems, the first input of which is connected to the output of the beam-forming device; fiber optic communication line, the inputs of which are connected to the outputs of the block of radio modems; a device for generating an output signal, the inputs of which are connected to the outputs of the fiber optic communication line; transmitting HEADLIGHT, the inputs of which are connected to the outputs of the output signal generating device; a local data transmission system connected to the output of the calculator, to the second input of the beam-forming device, to the second and third inputs of the block of radio modems; special communication manager software connected by a communication line to a local data network. 2. The antenna system according to claim 1 consists of an active phased antenna array, structurally implemented as a system of ring antenna sublattices of weakly directed active elements, concentrically placed on a collapsible vertical mast, up to 18 m high, and differs in that it forms optimal, in the sense of criterion for minimizing the standard error of the estimated parameters, the approximation of a uniform radiation pattern in the upper hemisphere due to the placement of one to nine annular sublattices with a radius of 0.5 to 2 m and with the number of elements from 3 to 13 in each sublattice, as well as adjusting the distance between the sublattices in height, with a minimum distance of 0.5 m, and the angle of rotation of each ring antenna sublattice relative to other sublattices. 3. The adaptive radio line according to claim 1, characterized in that the VHF, decameter band of radio waves and fiber optic communication are used as the data transmission network. 4. Adaptive radio link under item 1, characterized in that all its elements are made using digital technology.

Images