RU125724U1 - METHOD FOR FORMING SIGNALS AND TRANSMISSION OF INFORMATION IN THE RADAR RECOGNITION SYSTEM - Google Patents

Abstract

A method of generating signals and transmitting information in a radar recognition system, which consists in the fact that carrier and clock signals are generated on the transmitting side, a pseudorandom sequence (PSP) is generated from the clock signal, which is phase-controlled by the carrier signal and generated at the carrier frequency the phase-shifted signal is amplified and radiated into a space, characterized in that the transmitted information code is divided into n information blocks of the same length, each of They encode their PSP, which is the product of the covering PSP by the corresponding Walsh function, the number of which is uniquely determined by the binary code of the information block, and on the receiving side, for each received information block, the Walsh function number is determined, a sequence of these numbers is obtained, and the transmitted information code is restored from it.

Description

The proposed utility model relates to the field of radar, radio communications, radio navigation and radio control and can find application in radar recognition systems (RLO), as well as in communication systems with noise-like signals.

A known method of generating query signals in the form of pulse-time codes emitted at a fixed frequency. With this method, a code combination in the form of a set of units and zeros is represented in the form of pulses (in place of a unit) or their absence (in place of zero). The so-called smooth (narrow-band or simple) pulses are used. The method is used in the currently most common request-response systems of the Mark type (Mk-10 and Mk-12), as well as in the domestic system “Password” [Radio-electronic systems: Basics of construction and theory. Directory. Ed. 2nd, rev. and add. Ed. J.D. Shirman. - M .: Radio engineering, 2007, S.412-413]. The main characteristics of such systems are imitation resistance and secrecy.

In the "Password" system, the interrogation signal includes a binary information code at 44 positions formed by a cryptographic device [Radio-electronic systems: Basics of construction and theory. Directory. Ed. 2nd, rev. and add. Ed. J.D. Shirman. - M .: Radio engineering, 2007, S.413]. The disadvantage of this method of generating a query signal is its low noise immunity.

It is known that to increase the noise immunity, immitability, and stealth of radar recognition systems, instead of simple signals, noise-like (broadband) signals (BPS) can be used [Radar systems of multifunctional aircraft. T.1. Radar - the information basis of the fighting of multifunctional aircraft. Systems and algorithms for primary processing of radar signals. Ed. A.I. Kanaschenkov and V.I. Merkulov. - M .: Radio engineering, 2006].

Known methods for transmitting information in communication systems with noise-like signals [Patent No. 2085046 "System for transmitting discrete information"; Patent No. 22169660 “Radio communication line”; Noise-like signals in information transmission systems. Ed. V. B. Pestryakova. - M .: Owls. Radio, 1973]. Known communication systems use noise-like signals (SHPS) obtained as a result of phase-shift keying of a carrier frequency signal by a pseudo-random sequence (PSP). In these communication systems, each bit of the transmitted information is encoded by the SRP, which allows for high noise immunity. However, such systems have a low information transfer rate, which is their disadvantage.

There is also known a method of transmitting information in a communication system with noise-like signals [L. Varakin Communication systems with noise-like signals. - M .: Radio and communications, 1985, S.16-18]. A known method of transmitting information includes the formation of carrier and clock signals. PSP is formed from the clock frequency signal and its phase manipulation is performed by a binary sequence of pulses coming from the information source. In the process of phase manipulation, depending on what needs to be transmitted (1 or 0), the pulses of the information source are replaced by a direct or inverse SRP. The carrier frequency signal is phase-manipulated (0.180) by a pseudo-random pulse train, phase-manipulated from the information source. The signal formed at the carrier frequency is amplified and emitted through a communication channel.

The disadvantages of the described method are: low information transfer rate, since only one bit of information can be transmitted during the memory bandwidth; low imitability and secrecy of the communication system, since only one memory bandwidth is used to encode information from the source.

The first of these disadvantages is eliminated by the methods described in patents No. 2279183 and No. 2286017 "Method for transmitting information in a communication system with noise-like signals." The closest in technical essence and the set of essential features to the claimed method of generating signals and transmitting information in a radar recognition system is a method of transmitting information in a communication system with noise-like signals [Patent No. 2286017], which is chosen as a prototype. With this method, carrier and clock signals are generated. The SRP is formed from the clock frequency signal, which is manipulated in phase from the information source, and the carrier signal is phase-manipulated by a pseudo-random pulse sequence, phase-manipulated from the information source. On the transmitting side, digital data coming from the source of information for a time interval equal to the period of the SRP, one-to-one transforms the elements of the generated SRP into a shift relative to the elements of the previously formed SRP. The signal formed at the carrier frequency is amplified and emitted through a communication channel. On the receiving side, the magnitude of this shift is determined and converted into digital data of the received information. This method allows for a time equal to the period of the SRP, to increase the speed of information transfer in log ₂ N + 1 times (where N is the number of elements of the SRP), however, as previously discussed methods when using them in the recognition system, does not provide the required imitation resistance and stealth .

The inventive method of generating signals and transmitting information in a radar recognition system can improve the imitability and stealth of the identification system. This is achieved due to the fact that the transmitted information code (m-bit code combination) is divided into n code combinations of lower bit capacity k (k <m), called information blocks, each of which is encoded by its own memory bandwidth. In this case, on the transmitting side, instead of one SRP, a derived signal system is created on the basis of an array of covering pseudorandom sequences and a system of Walsh functions, which are generated quite simply and provide the formation of SHPS with good correlation properties [L. Varakin. Communication systems with noise-like signals. - M .: Radio and communications, 1985, S.110-114].

An array of covering PSP {G} is formed in a known manner [Noise-like signals in information transmission systems. Ed. V. B. Pestryakova. - M .: Owls. Radio, 1973, S.131-132] by modulo addition of two two M-sequences, taken from a common array of M-sequences, with different initial values in the shift registers

where M _i , M _j are two M-sequences with numbers i and j from a common array of M-sequences;

Z ₀ - the initial value of the shift register for M _i ;

Z _i = Z ₀ + ΔZ is the initial value of the shift register for M _j ;

ΔZ is the difference between the initial values of the shift registers for M _j and M _i .

M-sequences are periodic, therefore the length L _M (number of characters) of the used M-sequences is chosen equal to the period and is calculated by the formula L _M = 2 ^k , where k is the bit depth of the register.

информационных шумоподобных импульсов, следующих друг за другом непрерывно, без временных интервалов. Знак < > означает округление до большего целого числа. Внутри каждого информационного импульса (

- номер импульса) осуществляется кодирование псевдослучайной последовательностью S^(t), массив которых {S} формируется путем умножения накрывающей ПСП на соответствующую функцию УолшаThe system of Walsh functions includes N _w = 2 ^k Walsh functions, using each of which k bits of information are encoded. So, if it is necessary to transmit a B bit of information code (B-bit code combination), then the request signal is generated in the form of a sequence

information noise-like pulses following each other continuously, without time intervals. The sign <> means rounding to a larger integer. Inside each information impulse (

- pulse number) is encoded by a pseudo-random sequence S ^(t) , the array of which {S} is formed by multiplying the covering SRP by the corresponding Walsh function

- модулирующая ПСП для t-го информационного импульса;Where

- modulating SRP for the t-th information pulse;

- накрывающая ПСП с номером γ

для t-го импульса;

- covering PSP with number γ

for the t-th pulse;

- функция Уолша с номером l

для t-го импульса.

- Walsh function with number l

for the t-th pulse.

определяется числом, которому соответствует двоичный код соответствующего информационного блока. Например, если информационный блок состоит из восьми элементов и имеет вид 00000110, то этому коду соответствует число 6, то есть будет выбрана функция Уолша

.The number l of the Walsh function for the t-th information pulse

is determined by the number to which the binary code of the corresponding information block corresponds. For example, if the information block consists of eight elements and has the form 00000110, then this code corresponds to the number 6, that is, the Walsh function will be selected

.

The volume (N _G ) of the array covering the SRP {G} is determined by the formula

- число сочетаний из N_M по 2;Where

- the number of combinations of N _M 2;

N _M is the total volume of the array of orthogonal M-sequences;

N _Δz - the number of options ΔZ.

The volume (N _s ) of the SRP array {S} is determined by the formula

where N _W is the volume of the array of Walsh functions.

As an example, suppose you want to transfer B = 44 bits of an information code (as in the Password system), and M-sequences are formed using an eight-bit register (k = 8). Then we get:

информационных шумоподобных импульсов, следующих друг за другом непрерывно, без временных интервалов;the request signal is formed as a sequence

information noise-like pulses following each other continuously, without time intervals;

the total volume of the array of orthogonal M-sequences N _M = 16 [Varakin L.E. Communication systems with noise-like signals. - M .: Radio and communications, 1985, p. 59];

the number of variants of the differences of the initial values of the shift registers N _Δz = 2 ^k -1 = 2 ⁸ -1 = 255;

the length of the M-sequences, as well as those covering the SRP G formed on their basis, is L _M = L _G = 2 ^k = 2 ⁸ = 256;

the volume of the array of Walsh functions N _W = 2 ^k = 2 ⁸ = 256.

Substituting the indicated values in formulas (3), (4), we obtain

;

;

N _s = N _G · N _W = 30600 · 256 = 7833600.

The large volume of the SPS array {S} used in coding information pulses (N _s ≅ 7.8 million) provides structural covertness of the interrogation signals, making it difficult for the enemy to open the modulating SPS (during the time when the enemy still makes sense to use information about the opened structure signal).

. Сигнал несущей частоты манипулируют по фазе псевдослучайной последовательностью импульсов S^(t). Сформированный на несущей частоте фазоманипулированный сигнал (информационный импульс) усиливают и излучают в пространство. На приемной стороне для каждого принятого информационного импульса определяют номер функции Уолша, получают последовательность этих номеров и восстанавливают по ней переданный информационный код.Thus, with the claimed method, the transmitted information code (m-bit code combination) is divided into n code combinations of lower bit capacity k (k <m), called information blocks. On the transmitting side, carrier and clock signals are generated. From the clock signal form an array of covering SRP {G}. A digital code coming from an information source (cryptographic device) during the duration of one information block is uniquely converted into the number l of the Walsh function. For each information block, a phase-shift signal (SRP) S ^(t) is generated, which is the product of one of the SRP array {G} by the corresponding Walsh function

. The carrier signal is phase-manipulated by a pseudo-random pulse train S ^(t) . The phase-shift signal (information pulse) formed at the carrier frequency is amplified and radiated into space. On the receiving side, for each received information pulse, the Walsh function number is determined, a sequence of these numbers is obtained, and the transmitted information code is restored from it.

New features with significant differences are:

1. The partition of the transmitted information code into n information blocks, each of which is encoded by its own SRP, which is a product of the covering SRP by the corresponding Walsh function.

2. Unambiguous conversion of each information block into the number of the corresponding Walsh function.

These signs have significant differences, because in known methods are not found.

The use of these features, along with the large volume of the SFP {S} array used in coding information pulses, will ensure structural stealth of the interrogation signals and a low probability of their imitation by the adversary.

In FIG. The block diagram of the transmitter is given [L. Varakin Communication systems with noise-like signals. - M .: Radio and communications, 1985, p.16], explaining the proposed method for generating signals and transmitting information in a radar recognition system, where the structure of the phase modulator and phase-shift signal generator, determined by the above essential features, is shown in more detail. To simplify the communication scheme of the control unit and the formation of control signals (synchronizer) 12 with other blocks are shown conditionally (dashed lines, each of which can be a set of different clock pulses).

записывается в свою ячейку под номером l запоминающего устройства (ЗУ) 3, образуя массив {W} функций Уолша объемом N_W. Аналогично каждая из сформированных генератором 9 накрывающих ПСП записывается в свою ячейку запоминающего устройства 10, образуя массив {G} накрывающих ПСП объемом N_G. По сигналу управления, поступающему от блока управления и формирования управляющих сигналов 12, с первого выхода криптографического устройства 1 в k-разрядный регистр адреса 2 записывается первый (t=1) блок информационного кода, а со второго его выхода в регистр адреса 11 записывается код адреса запоминающего устройства 10. Записанная в регистре 2 кодовая комбинация представляет собой двоичный код адреса (номера ячейки памяти) запоминающего устройства 3, который по сигналу считывания поступает в l-тую ячейку запоминающего устройства 3. Аналогично записанная в регистре 11 кодовая комбинация представляет собой двоичный код адреса (номера ячейки памяти) запоминающего устройства 10, который по сигналу считывания поступает в γ-ую ячейку запоминающего устройства 10. В результате с выхода ЗУ 3 на первый вход умножителя 4 поступает функция Уолша

с номером l, а с выхода ЗУ 10 на второй вход умножителя 4 поступает накрывающая ПСП

c номером γ. После посимвольного перемножения функции Уолша

на накрывающую ПСП

(формула (2)) на выходе умножителя 4 получаем последовательность ШПС в виде фазоманипулированных (ФМ) сигналов, переносящую информационный код первого блока (ПСП S⁽¹⁾). Эта последовательность поступает в модулятор 5, в котором осуществляется балансная модуляция колебания, вырабатываемого генератором 8 несущей частоты, ФМ сигналом. После усиления сформированного сигнала в усилителе мощности 6 сигнал поступает на антенну и излучается в пространство.The clock pulses from the control unit and the formation of control signals 12 start the generators of the Walsh functions 7 and cover the SRP 9. Each of the Walsh functions generated by the generator 7 W _l

recorded in its cell under the number l of the storage device (memory) 3, forming an array {W} of Walsh functions of volume N _W. Similarly, each of the cover bandwidths formed by the generator 9 is recorded in its cell of the storage device 10, forming an array {G} of cover bandwidths of volume N _G. According to the control signal coming from the control unit and generating control signals 12, the first (t = 1) block of the information code is written from the first output of the cryptographic device 1 to the k-bit register of address 2, and the address code is written from its second output to the address register 11 memory device 10. The code combination recorded in register 2 is a binary address code (memory cell number) of memory device 3, which, by a read signal, enters the l-th cell of memory device 3. Similar but the code combination recorded in the register 11 is a binary code of the address (memory cell number) of the storage device 10, which, according to the read signal, enters the γ-th cell of the storage device 10. As a result, the Walsh function from the output of the memory 3 to the first input of the multiplier 4

with the number l, and from the output of the memory 10 to the second input of the multiplier 4 receives the covering bandwidth

with number γ. After symbol-wise multiplication of the Walsh function

on covering PSP

(formula (2)) at the output of the multiplier 4, we obtain the NPS sequence in the form of phase-shifted (FM) signals that transfers the information code of the first block (SRP S ⁽¹⁾ ). This sequence enters the modulator 5, in which the balanced modulation of the oscillation generated by the generator 8 of the carrier frequency, the FM signal. After amplification of the generated signal in the power amplifier 6, the signal enters the antenna and is radiated into space.

Simultaneously with the read signal from register 2 of the first block of the information code, the second (t = 2) block of the information code is written into it and the process described above is repeated until all n blocks of the information code are transmitted.

Claims (1)

A method of generating signals and transmitting information in a radar recognition system, which consists in the fact that carrier and clock signals are generated on the transmitting side, a pseudorandom sequence (PSP) is generated from the clock signal, which is phase-controlled by the carrier signal and generated at the carrier frequency a phase-shifted signal is amplified and radiated into a space, characterized in that the transmitted information code is divided into n information blocks of the same length, each of They encode their PSP, which is the product of the covering PSP by the corresponding Walsh function, the number of which is uniquely determined by the binary code of the information block, and on the receiving side, for each received information block, the Walsh function number is determined, a sequence of these numbers is obtained, and the transmitted information code is restored from it.

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