RU189301U1 - A device for processing signals of space radio navigation systems - Google Patents

Abstract

A device for processing signals of space radio-navigation systems (CRNS) includes a housing in which serially connected analog channel 1 for receiving L1 frequency signals in a 20 MHz band, analog signal-digital conversion (ADC) module CRNS, and digital heterodyning module 4 CRNS are installed. The second input of module 4 is connected to the output of module 3 for calculating the Doppler frequency. The first output of digital heterodyning module 4 is connected via module 9 to read the navigation message with the first input of module 12 for allocating crypto-resistant data sequence W (h). The second output of digital heterodynamic module 4 is connected via module 6 to search for the beginning of an open ranging code period, through module 8 phase correction and open and closed code separation by quadratures, through module 10 decoding a closed code by threshold processing of the selected signal quadrature with tracking the boundary values of the signal level change with the second input of the module 12 allocation cryptographic data sequence W (h), the third input of which is connected to the output of the module 11 to generate an open accurate far of the measured code P. The second input of module 6 is connected to the output of module 5 for generating an open coarse ranging C / A code, and its output through module 7 for measuring phase correction is connected to the second input of module 8. The useful model has improved the accuracy of decoding CRNS signals by 5-15 % 3 hp f-ly, 6 ill.

Description

The field of technology.

The invention relates to special calculators and can be used to process signals from space radio navigation systems.

The level of technology.

Known means and methods for processing signals of space radio navigation systems / 1-4 /.

The closest (by purpose and technical nature) to the claimed utility model is a device for processing signals of space radio navigation systems / 4 /.

частоты L1 в полосе 20 МГц с общедоступным кодом и аналоговый канал приема спутниковых сигналов с закрытым кодом на частоте L2 и преобразованием частоты L2 вниз, соединённые через многоразрядные цифровые фильтры нижних частот (ФНЧ с модулем выделения из принятых сигналов криптостойкой последовательности данных W(h). При этом модуль выделения информационных данных W(h) выполнен в виде банка следящих контуров фазовой автоподстройки частоты (ФАПЧ).The known device for processing signals of space radio navigation systems (CRNS) / 4 / analog channel receiving satellite signals

L1 frequencies in the 20 MHz band with a publicly available code and an analog channel for receiving satellite signals with a closed code at the L2 frequency and converting the L2 frequency downward, connected via multi-bit digital low-pass filters (low-pass filter to the extraction module from received signals of the crypto-resistant data sequence W (h). In this case, the module for extracting information data W (h) is made in the form of a bank of tracking phase-locked loops (PLL).

A disadvantage of the known device for processing signals CRSS is relatively low accuracy CRSS decoding, associated with the necessity of high precision measurement of the Doppler frequency f and the _extra initial phase φ _N KNRS signals.

The objective and technical result of the utility model is to improve the decoding accuracy of CRNS signals.

The essence of the utility model.

частоты L1 в полосе 20 МГц и модуль выделения из них криптостойкой последовательности данных W(h), согласно полезной модели дополнительно содержит модуль аналого-цифрового преобразования (АЦП) принятых сигналов, модуль расчета частоты Доплера, модуль цифрового гетеродинирования сигналов

, модуль генерации открытого грубого дальномерного кода С/А, модуль поиска начала периода открытого дальномерного кода, модуль измерения фазовой поправки, модуль фазовой коррекции и разделения открытого и закрытого кода по квадратурам, модуль чтения навигационного сообщения, модуль декодирования закрытого кода путем пороговой обработки выделенной квадратуры сигнала с отслеживанием граничных значений изменения уровня сигнала и модуль генерации открытого точного дальномерного кода Р.The solution of the task and the achievement of the claimed technical result is ensured by the fact that the device for processing signals of space radio navigation systems, including an analog channel for receiving satellite signals

according to the utility model, the L1 frequency in the 20 MHz band and the module for extracting from them a cryptoresistant data sequence W (h) further comprises an analog-to-digital conversion (ADC) module of received signals, a Doppler frequency calculation module, a digital heterodyning module

, open coarse-range ranging C / A code generation module, open period start-up code search module, phase correction measurement module, phase correction and open and closed code separation module, read navigation message module, closed code decoding module by threshold processing of the selected quadrature signal with tracking the boundary values of changes in the signal level and the module generating an open accurate ranging code P.

At the same time, the output of the analog satellite reception channel is connected to the first input of the module for extracting cryptoresistant data sequence W (h) through the serially connected ADC module, digital heterodyning module, module for searching for the beginning of an open ranging code period, module for phase correction and separation of open and closed code and a module decoding closed code. The second input of the decoding module is connected to the output of the open accurate ranging code P generation module, and its third input is connected to the second output of the digital heterodyning module via the navigation message reading module. The second input of the digital heterodyning module is connected to the output of the Doppler frequency calculation module of satellite signals. The second input of the search module of the beginning of the period of the open ranging code is connected to the output of the module of the search for the beginning of the period of the open ranging code. The second output of the search module of the beginning of the period of the open ranging code is connected via the phase correction measurement module with the second input of the phase correction and separation module of the open and closed code.

The introduction of these differences improves the accuracy of decoding signals KRNS with simultaneous reduction in time to read the navigation message.

Improving the decoding accuracy of the CRNS signals and extracting from them a crypto-resistant sequence of data W (h) for each NA is provided by generating an open coarse ranging code C / A, phase correction, separating open and closed code by quadratures and threshold processing of the selected quadrature of the signal with tracking the boundary values change its level.

It does not require accurate measurement of the Doppler frequency f _additional signals KRNS inherent in the prototype of the invention. Reading the navigation message is performed without two-frequency processing of the CRNS signals and without using a multitude of inertial PLL tracking loops for accurate measurement of the Doppler frequency f of the _additional CRNS signals.

This technical advantage, along with an increase in the decoding accuracy of the CRNS signals, provides a drastic reduction in the time of the specified decoding.

The essence of the utility model is illustrated by the figures shown in FIG. 1- FIG. 6

FIG. 1 shows a functional diagram of the device for processing signals KRNS; in fig. 2- view of the CRNS signal in time (Fig. 2a) and spectral (Fig. 2b) form; in fig. 3-scheme of digital heterodyning signals KRNS; in fig. 4 is a timing diagram of the P (Y) and C (A) signals in a selected area after digital heterodyning and phase correction of the signal; in fig. 5 is a timing diagram of P (Y) signals and the results of their decoding D (h); Fig. 6 shows a comparative evaluation of the decoding results in the proposed utility model and in the known CRNS signal processing device, as a function of the probability (P _d ) of accurate decoding of the signal from the signal-to-noise ratio (S / N).

FIG. 1-6 marked:

1 - analog channel receiving signals of the L1 frequency in the 20 MHz band.

2 - analog-to-digital conversion ADC module.

3 - Doppler frequency calculation module.

4 - digital heterodyning module

5 - module for the generation of open coarse ranging code C / A

6 - search module of the beginning of the period of open ranging code

7 - phase correction measurement module

8 - module of phase correction and separation of open and closed code by quadratures

9 - navigation message reader module

10 - a decoding module of a closed code by threshold processing of the selected signal quadrature with tracking the boundary values of the signal level change;

11 - module for generating an open, accurate ranging code P;

12 - module allocation crypt-resistant data sequence W (h).

Disclosure of the essence of the utility model.

A device for processing signals of space radio navigation systems (CRNS), includes a housing in which are installed serially connected analog channel 1 receiving signals of the L1 frequency in the 20 MHz band, module 2 analog-to-digital conversion (ADC) signals KRNS, module 4 digital heterodyning signals KRNS. The second input of module 4 is connected to the output of module 3 for calculating the Doppler frequency. The first output of digital heterodyning module 4 is connected via module 9 to read the navigation message with the first input of module 12 for allocating crypto-resistant data sequence W (h). The second output of digital heterodynamic module 4 is connected via module 6 to search for the beginning of an open ranging code period, through module 8 phase correction and open and closed code separation by quadratures, through module 10 decoding a closed code by threshold processing the selected quadrature of the signal with tracking the boundary values of the signal level change with the second input of the module 12 allocation cryptographic data sequence W (h), the third input of which is connected to the output of the module 11 to generate an open accurate far dimensional code R. The second input unit 6 connected to the output unit 5 generate open coarse ranging code C / A, and the output unit 7 through the measurement of the phase correction is coupled to the second input unit 8.

выполнен в виде умножителя преобразуемого сигнала

на комплексный гармонический сигнал

в соответствии с выражением Module 4 digital heterodyning signal

made as a multiplier of the signal to be converted

on complex harmonic signal

according to the expression

(one)

Where:

и

- реальная и мнимая составляющие квадратурного сигнала; f_доп – частота Доплера, обусловленная движением КА по известной траектории относительно точки приема сигнала;

and

- real and imaginary components of the quadrature signal; f _SS - the Doppler frequency, due to the movement of the spacecraft along a known trajectory relative to the point of reception of the signal;

φ _N - random initial phase of the received signal, due to the uncertainty of the length of the route of its passage;

- принятый и оцифрованный сигнал на частоте f_L1;

- the received and digitized signal at the frequency f _L1 ;

f _IF - intermediate frequency at the output of the analog reception module, equal to the difference f _L1 and the local oscillator frequency f _G ;

f _D - sampling frequency.

на измеряемую по известному открытому коду величину фазовой поправки Δφ_Н из условий:Module 8 phase correction and separation of open and closed code by quadratures made with the possibility of phase correction signal

measured by known open code phase correction value Δφ _N from the conditions:

(2) (3)

(four)

(five)

(6)

Where:

k ^* is the reference number of the signal corresponding to the beginning of the period of the open ranging code C / A;

N is the number of samples corresponding to the length of the open ranging code C / A;

– поправка, учитывающая четверть комплексной плоскости, в которой располагается комплексное число

и вычисляемая в зависимости от знаков компонент

.

- an amendment that takes into account a quarter of the complex plane in which the complex number is located

and calculated depending on the signs of the component

.

Module 10 decoding the closed code is made in the form of a block of threshold processing of the selected signal quadrature from the condition:

(7)

(eight)

Where:

= (V_max+V_min)/2 –порог принятия решения, равный среднему значению границ изменения сигнала;

= (V _max + V _min ) / 2 - decision threshold equal to the average value of the signal change limits;

– свертка внутри одного бита кода;

- convolution inside one code bit;

M is the number of signal samples equal in duration to one bit of the code;

h is the number of the code bit being analyzed;

L is the total number of bits in the analyzed sample.

A device for processing signals KRNS, works as follows.

производится (фиг. 3) путем умножения преобразуемого сигнала

модуля 3, на комплексный гармонический сигнал

в соответствии с выражением (1). Результаты цифрового гетеродинирования

по первому выходу модуля 4 передаются в модуль 6, а по второму выходу - на модуль 9 чтения навигационного сообщения

. Прочитанное в модуле 9 сообщение в сигнале КРНС на частоте L1 передается на первый вход модуля 12 для выделения криптостойкой последовательности данных W(h). Одновременно в модуле 6 производится поиск начала периода открытого дальномерного кода С/А на основе генерации открытого грубого дальномерного кода С/А в модуле 6. Найденное в модуле 6 начало кода С/А передается по первому выходу в модуль 8 фазовой коррекции и разделения открытого и закрытого кода по квадратурам, а по второму выходу в модуль 7 измерения фазовой поправки Δφ_Н. Далее в модуле 8 проводят фазовую коррекцию сигнала

из условий (2) – (6) на величину фазовой поправки Δφ_Н. Откорректированный в блоке 8 сигнал

передается на модуль 10. В модуле 10 производится декодирование закрытого кода путем пороговой обработки выделенной квадратуры сигнала с отслеживанием граничных значений изменения уровня сигнала КРНС. Пороговая обработка выделенной квадратуры сигнала производится из условий (7) – (8). Результаты пороговой обработки в модуле 10 передаются на второй вход модуля 12 выделения криптостойкой последовательности данных W(h). Одновременно в модуле 11 производится генерация открытого точного дальномерного кода Р и передача его на третий вход указанного выше модуля 12. На основе входных данных в модуле 12 производится корреляционная обработка принятых сигналов КНРС и выделение из них криптостойкой последовательности данных W(h) и декодирование информационных сообщений спутниковых систем связи.Channel 1 receives CRNS signals on the L1 frequency in the 20 MHz frequency band. Received signals KRNS in channel 1 are amplified and transmitted to the module 2 ADC. In module 2, the analogue CRS signals are converted into digital form and transmitted to the digital heterodyning module 4. In module 4, digital signal heterodyning

produced (Fig. 3) by multiplying the converted signal

module 3, on the complex harmonic signal

in accordance with the expression (1). Digital heterodyning results

on the first output of module 4 are transmitted to module 6, and on the second output - on module 9 of reading the navigation message

. The message read in module 9 in the CRNS signal at the frequency L1 is transmitted to the first input of module 12 to highlight a cryptographically secure data sequence W (h). At the same time, module 6 searches for the beginning of the open range C / A period based on the generation of the open coarse range C / A code in module 6. The beginning of the C / A code found in module 6 is transmitted to the phase correction and separation module 8 at the first output. closed code by quadratures, and the second output in module 7 of the measurement of phase correction Δφ _N. Next, in module 8 phase correction signal

from conditions (2) - (6) on the value of the phase correction Δφ _N. Corrected in block 8 signal

transmitted to module 10. In module 10, the closed code is decoded by threshold processing of the extracted signal quadrature with tracking of the boundary values of the change in the level of the CRNS signal. The threshold processing of the selected signal quadrature is performed from conditions (7) - (8). The results of the threshold processing in module 10 are transmitted to the second input of the module 12 of the allocation of cryptoresistant data sequence W (h). At the same time, module 11 generates an open, accurate ranging code P and sends it to the third input of module 12. The input data in module 12 is used to correlate the received CNRS signals and extract cryptographic data sequence W (h) from them and decode information messages satellite communication systems.

Industrial Applicability.

The utility model has been developed at the level of a technical proposal, a mathematical model, and a CRNS signal processing software.

The results of mathematical modeling (Fig. 6) showed the possibility of improving the accuracy of decoding CRPS signals by 5-15% and, as a result, to achieve the stated technical result of the utility model.

Information sources.

1. OPTIMUM SEMI-CODELESS CARRIER PHASE TRACKING OF L2 T. W. Woo NavCom Technology, Inc., Redondo Beach, California (14) -17, 1999).

2. US 3047660 John P. Costas "Radio Communication System Receiver".

3. Digital radio receiving systems: a Handbook / MI Zhodzishsky, RB Mazepa, etc. / Edited by M.I. Zhodzisz. - M .: Radio and communication, 1990, 208 p.

4. RU 2363099, 09/20/2008.

Claims (28)

1. A device for processing signals of space radio navigation systems, including an analog channel for receiving satellite signals

L1 frequencies in the 20 MHz band and a module for extracting cryptoresistant data sequence W (h) from them, characterized in that it further contains an analog-to-digital conversion (ADC) module of received signals, a Doppler frequency calculation module, a digital heterodyning module

, open coarse-range ranging C / A code generation module, open period start-up code search module, phase correction measurement module, phase correction and open and closed code separation module, read navigation message module, closed code decoding module by threshold processing of the selected quadrature signal with tracking the boundary values of changes in the signal level and the module generating an open accurate ranging code P, and the output of the analog reception channel satellites x signals connected to the first input of the module for extracting cryptoresistant data sequence W (h) through the serially connected ADC module, digital heterodyning module, open period ranging code beginning search module, open code and close code phase correction and separation module, second input which is connected to the output of the open accurate ranging code P generation module, and the third input of the module for extracting a cryptoresistant data sequence W (h) through a reading module of the navigation message with the second output of the digital heterodyning module, the second input of which is connected to the output of the Doppler frequency calculation module of the satellite signals, the second input of the open period ranging code start module is connected to the output of the open coarse range C / A generation module, the second output of the period beginning search module An open ranging code is connected via a phase correction measurement module with a second input of a phase correction and open code separation module. 2. The device according to p. 1, characterized in that the module digital heterodyning signal

made as a multiplier of the signal to be converted

on complex harmonic signal

according to the expression Where:

and

- real and imaginary components of the quadrature signal; f _SS - the Doppler frequency, due to the movement of the spacecraft along a known trajectory relative to the point of reception of the signal; φ _N - random initial phase of the received signal, due to the uncertainty of the length of the route of its passage;

- the received and digitized signal at the frequency f _L1 ; f _IF - intermediate frequency at the output of the analog reception module, equal to the difference f _L1 and the local oscillator frequency f _G ; f _D - sampling frequency. 3. The device according to p. 1, characterized in that the module phase correction and separation of open and closed code quadratures made with the possibility of phase correction signal

measured by known open code phase correction value Δφ _N from the conditions: Where: k ^* is the reference number of the signal corresponding to the beginning of the period of the open ranging code C / A; N is the number of samples corresponding to the length of the open ranging code C / A;

- an amendment that takes into account a quarter of the complex plane in which the complex number is located

and calculated depending on the signs of the component

. 4. The device according to claim 1, characterized in that the decoding module of the closed code is made in the form of a block of threshold processing of the selected signal quadrature from the condition: Where:

= (V _max + V _min ) / 2 - decision threshold equal to the average value of the signal change limits;

- convolution inside one code bit; M is the number of signal samples equal in duration to one bit of the code; h is the number of the code bit being analyzed; L is the total number of bits in the analyzed sample.

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