RU2338261C1 - Method of telemetering signal recording and processing with time channeling - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: method consists, that beep signal radiotelemetering signal is received, transformed, recorded and analysed. Transformation stage implies formation of instantaneous quadrature components of telemetering signal at intermediate frequency. Obtained data is digitised. Analysis stage includes restoration of temporal pattern of group telemetering signal. Thus within each interval corresponding to a priori known telemetering signal cycle duration, for resulted quadrature components and resulted clock signal, cross-correlation function is calculated. Then cross-correlation function is calculated. Specified range is used to form arrays corresponding to separate cycles of telemetering signal. Within V cycles duration interval arrays are summed. Maximal total function indicates cycle phase. Based on cycle phase and a priori known telemetering signal pattern, arrays corresponding to resultant separate discrete messages of group telemetering signal are formed.

EFFECT: reduced telemetry losses associated with real-time synchronisation system response time.

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Description

The invention relates to radio engineering, television measurement technology and can be used for systems for receiving, recording and processing telemetric signals with time division of channels.

A known method of receiving, converting and recording a telemetric signal with a time division of channels, which consists in receiving and converting a radio signal into a video signal, extracting clock signals (markers), extracting measurement information, generating service information and time signals with subsequent recording of all information on a magnetic medium (System analysis measuring systems / V.V. Vasiliev, N. B. Rezvetsov, A. V. Anoshkin and others. M .: Strategic Rocket Forces, 1994, p. 172-173).

A disadvantage of the known method for receiving, recording and processing telemetry signals with time division of channels is that the signal is recorded after the detection, synchronization and demodulation procedures, which under the influence of strong noise leads to the appearance of so-called abnormally large (abnormal) errors that exceed valid values. This leads to poor-quality assessment of the temporal structure of the telemetry signal, distortion of the transmitted telemetry information, and, as a result, to the loss of telemetry results. Errors in the system of symbol synchronization (channel synchronization) lead to errors in determining the transmission time of symbols (channel intervals). When the error does not exceed the time duration of the symbol (channel interval), it only affects the operation of the resolver, increasing the likelihood of an erroneous decision (error in the parameter estimation). Errors of symbolic (channel) synchronization exceeding the duration of a symbol (channel interval), as well as errors in the synchronization system, according to words and frames, cause incorrect separation of information. This leads to a complete loss of telemetric measurements (samples) in the faulty areas. In this regard, in the synchronization systems of hardware execution, functioning in real time, it is necessary to achieve a compromise. On the one hand, to ensure high noise immunity, it is necessary to increase the analysis interval of the received data. But this leads to an increase in processing time, i.e. the synchronization system becomes "inertial", which, when receiving and processing a signal in real time, leads to the loss of a telemetric message. This is especially true for radio lines with fading and systematic violations (interruptions) in radio communications, in particular for telemetry systems. These reasons lead to the need to limit the analysis interval, which accordingly reduces the noise immunity of existing systems.

To eliminate this drawback, it is necessary to register a telemetric signal before performing detection, synchronization and deciding on the transmitted message, and, at the stage of analyzing the recorded data, to restore the temporal structure of the signal by the accumulation method, which assumes that when receiving an incoherent sequence of radio pulses, the quadrature summation of the envelopes of the mutual correlation function of the received signal and reference marker.

The technical result achieved in this case is to reduce the loss of television measurements associated with the inertia of synchronization systems operating in real time.

The specified technical result is achieved by the fact that in a known method of receiving, recording and processing a telemetric signal, which consists in receiving and converting a radio signal into a video signal, extracting clock signals (markers), extracting measurement information, generating service information and time signals with subsequent recording of all information to magnetic carrier, operations introduced: the formation of instantaneous values of the quadrature components of the intermediate frequency signal and the conversion of the received flows OF DATA displaying quadrature components telemetry radio to digital form for registration of the whole sequence of digital data on the memory device; restoration of the temporal structure of the recorded data by calculating the square of the envelope of the mutual correlation function of the received signal and the reference marker (when processing data recorded under conditions of a low signal-to-noise ratio), forming arrays corresponding to individual cycles (frames) of the received signal, summing them up and determining the phase of the cycle to the maximum of the resulting function; the formation of sets corresponding to the transmission intervals of individual discrete messages based on a certain phase of the cycle, and their processing.

In order to reduce the amount of data recorded at an intermediate frequency, the sequence of instantaneous values of the quadrature components of the signal quantized by the level of samples, which are functionally related to the modulating function, must be stored. Two groups of samples of a high-frequency modulated signal with a known reference frequency ω ₀ fully represent quadrature amplitudes if the first group of samples is made at discrete time instants

T _k = kΔT _∂ , ΔT = nT _o = n2π / ω _o , k = 0, 1, 2 ...,

moreover, ΔT _∂ ≤1 / 2Δf _c , and the second group of samples is made at discrete time instants with the indicated characteristics, but shifted relative to the time instants of the first group by τ _c = π / 2ω _o .

Since the samples are taken at discrete time instants in accordance with the condition t _k = nk2π / ω _o , then

S ₁ (t _k ) = A (t _k ) cos [2πkn + θ (t _k )] = A (t _k ) cosθ (t _k ).

The second group of samples is shifted relative to the first by π / 2, therefore, we can write

Due to the fact that the modulating function changes much more slowly than the frequency of the carrier oscillation, we can assume that it is constant over the time interval τ _c = π / 2ω _o . And therefore, we can assume that

Signals S ₁ and S ₂ fully describe the quadrature components.

When implementing this method, readings of the second group can be made at discrete points in time, shifted relative to the first group not only by a quarter of the wavelength, but also by time intervals equal to

τ = n2π / ω ₀ + π / 2ω ₀ , n = 1, 2, 3 ...,

provided that τ≤ΔT _∂ = 1 / 2Δf _c .

The received signal is an additive mixture of the useful signal and noise, i.e. each sample will represent the sum of the signal and noise components

z _k = s _k + n _k .

Data obtained as a result of registration, may be represented as two sets {z _ck} and {z _sk}, which respectively represent the phase and quadrature components recorded telemetry signal whose dimensions are determined by the total number of discrete time k = 1, 2, ..., K.

As a basic approach, when reconstructing the temporal structure of a recorded telemetry signal, an approach is used based on an algorithm for estimating the temporal position of signal frame elements t _jr (moments corresponding to the beginning of channel intervals Δt _jr ), which are determined by the temporal position of the clock signals. This means that one of the main tasks in restoring the time structure of a telemetric signal is to evaluate the parameter τ ₀ , which characterizes the position of the clock signal relative to the beginning of the analysis. According to the provisions of the theory of statistical solutions in communication systems with a uniform distribution of the a priori probability density of the parameter τ _{0, the} estimate reduces to the rule of maximum likelihood function.

The restoration of the temporal structure of the recorded data is carried out on the basis of the implementation of algorithms for correlation processing of signals with random parameters, which is equivalent to calculating the envelope of the correlation function for all possible values of the desired parameter.

With a clock signal with incoherent pulses, the processing is reduced to calculating the envelope of the mutual correlation function on each cycle corresponding to the duration of the telemetric message frame. After that, a quadratic summation of the envelopes of the components of the mutual correlation function is performed. Based on this, the resulting algorithm can be expressed by the following expression:

, где k=1, 2,..., K-L - порядковый номер выборки на интервале анализа.The restoration of the temporal structure of the recorded data is realized by forming the squared envelope of the mutual correlation function for the entire analysis interval. After that, the obtained data is divided into sets that contain values related to individual cycles. T.O. first a column vector is formed

, where k = 1, 2, ..., KL is the serial number of the sample in the analysis interval.

, где b=1, 2,..., V - номера циклов, а p=1, 2,..., P - номер выборки в цикле. Данные вектора суммируются, что позволяет получить результирующий вектор

Решение о положении синхроимпульса принимается по индексу максимального элемента в векторе-столбце.The resulting vector is divided into many vectors

, where b = 1, 2, ..., V are the numbers of cycles, and p = 1, 2, ..., P is the number of samples in the cycle. The vector data is summed, which allows you to get the resulting vector

The decision on the position of the clock is made by the index of the maximum element in the column vector.

Based on the obtained data, arrays z _jr = {z _jrn } are _generated corresponding to the transmission intervals of individual discrete messages, which are subject to further processing in order to isolate the transmitted message.

When implementing the proposed method for recording and processing a telemetry signal with a time division of channels, the following operations are performed (Figs. 1, 2).

1. The formation of the time sampling frequency of the received telemetric radio signal z (t) in accordance with the frequency band of the radio path of the receiving device f _∂ ≥2Δf, _etc.

2. The formation of two data streams (Fig. 1), displaying discrete values of the quadrature components of the received telemetric radio signal z _c (t _k ) and z _s (t _k ), by temporal sampling by the samples shifted in time relative to each other by a quarter of the length of the carrier period oscillations τ _c = π / 2ω ₀ .

3. Converting the obtained quadrature components into digital form and recording a sequence of digital data on computer memory devices, the characteristics of which correspond to the requirements determined by the input data streams.

4. The formation, on the basis of a priori information about the telemetric signal, of discrete values of a single reference clock signal {x _l }, the dimension of which is determined by discrete samples l = 1, 2, ..., N _M , where N _M is the number of samples per clock signal .

5. Isolation from the registered sets {z _ck } and {z _sk } of data corresponding to the required analysis interval, and the calculation of dependencies

6. Calculation of the square of the envelope of the correlation function (when processing data representing a signal with incoherent clock pulses recorded under conditions of a low signal-to-noise ratio)

массивов

соответствующих отдельным циклам, по N_ц элементов в каждом, количеством V, где p=1, 2,..., N_ц - индекс элемента в цикле, а b=1, 2,..., V - номер цикла.7. The formation of the set of data

arrays

corresponding to individual cycles, with N _c elements in each, the number of V, where p = 1, 2, ..., N _C is the index of the element in the cycle, and b = 1, 2, ..., V is the number of the cycle.

8. On the interval corresponding to V periods of repetition of the clock signals, the determination of the phase of the cycle by the maximum of the resulting function (figure 2)

9. The formation of arrays z _jr = {z _jrn } corresponding to the transmission intervals of individual discrete messages Δt _jr , based on the determined periodicity of the synchronization signals N _c , which corresponds to the cycle duration T _c , and the phase of the cycle, valid for V periods, and also based on a priori known structure of a group telemetric signal.

10. Processing arrays {z _jrn } in order to decide on the transmitted message.

The proposed method for recording and processing a telemetric signal with a time division of channels provides the specified technical result - reducing the loss of television measurements associated with the inertia of synchronization systems operating in real time.

A comparative analysis with a known method showed that the proposed method for recording and processing a telemetry signal with a time division of channels includes new significant features set forth in the claims. Therefore, the technical solution meets the criterion of "novelty."

Since the required technical result is achieved by the entire newly introduced set of essential features that are not found in the well-known patent and scientific literature at the filing date, the technical solution meets the criterion of "inventive step".

The above information indicates the fulfillment of the following set of conditions when using the claimed technical solution:

- the proposed method is intended for use in industry, namely in radio engineering, in particular in stations for receiving, recording and processing telemetric information;

- for the claimed method in the form as described in the independent claims of the claims, the possibility of its implementation using known means and methods prior to the priority date is confirmed.

Therefore, the claimed technical solution meets the criterion of "industrial applicability".

When using the proposed method for recording and processing a telemetric signal with a time division, the loss of telemetric measurements associated with the inertia of synchronization systems operating in real time is reduced.

Claims (1)

A method for recording and restoring a group telemetric signal, namely, that a radio telemetric signal is received, converted, recorded and analyzed, characterized in that at the conversion stage, instant values of the quadrature components of the telemetric signal at an intermediate frequency are generated, the data obtained is converted to digital form, at the stage registration on the memory device register a sequence of digital data, at the analysis stage, the temporal structure of the group telemetry signal is restored, while on each interval corresponding to the a priori known duration of the telemetry signal cycle, the cross-correlation function is calculated for the data of quadrature components and the data of the reference clock signal, the value of the square of the envelope of the cross-correlation function is calculated, arrays corresponding to individual telemetry signal cycles are formed from the set of indicated values, on the interval of duration of V cycles, the arrays are summed up, the phase of the cycle is determined by the maximum of the total function, Based on the phase of the cycle and the a priori known structure of the telemetric signal, sets are formed that correspond to the data of individual discrete messages of the group telemetric signal.

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