Studying noise immunity of radio information transmission systems with noise-like phase-shift keyed signals and synchronization delay errors

Author(s):  
G. N. Maltsev ◽  
A. V. Evteev

Introduction: Radio information transmission systems with noise-like phase-shift keyed signals based on pseudo-random sequences have potential noise immunity provided by accurately tracking the delay of the received signal in the correlation receiver. When working with moving objects, the delay of the received signal varies continuously, and the reception quality for noise-like phase-shifted signals highly depends on the synchronization system operation and on the accuracy of estimating the received signal delay by the tracking system. To ensure the required signal reception quality, it is necessary to provide an informed choice of tracking system parameters, taking into account their effects, which are the random and systematic components of the delay tracking error, on the selected noise immunity indicator.Purpose: Analyzing how the errors in tracking the delay of a received phase-shift keyed signal based on a pseudorandom sequence by the synchronization system of a radio information transmission system can affect the probability of erroneous reception of an information symbol.Results: The calculation method was used to obtain families of dependencies of the probability of erroneous reception of an information symbol on the signal-noise ratio (SNR), and the values of the random and systematic components of the delay tracking error which are normalized to the capture band of the correlation receiver. It has been shown that at a fixed SNR, the values of the random and systematic components of the delay tracking error are critical for the erroneous reception probability. In all the cases discussed, all the dependencies are characterized by a slow change of the erroneous reception probability while the synchronization errors within the area of small SNR have fixed values. As the SNR value grows, the erroneous reception probability rapidly drops. To ensure the specified signal reception quality and the reliability of the selection of information symbols and messages in a radio information transmission system with noise-like phase-manipulated signals, its synchronization system requires a joint selection of the tracking system parameters, taking into account the limitations imposed by the operating conditions and technical implementation features.Practical relevance: The obtained results can be used in noise immunity analysis of radio information transmission systems with noise-like phase-shift keyed signals in a wide range of communication conditions, and in providing technical solutions for synchronization systems ensuring the required quality of signal reception.

Author(s):  
Georgy Maltsev ◽  
Andrey Evteev

The issues of ensuring the stability of delay tracking in synchronization systems of radio engineering systems when receiving phase-shift keyed signals with spectrum expansion based on pseudorandom sequences are considered. When working with moving objects, the delay of the received signal continuously changes, synchronization errors occur, and the quality of signal reception largely depends on the stability of the tracking scheme for the delay, characterized by the probability of tracking failure. Delay tracking is usually considered as the main task of the synchronization system of the considered radio systems with phase-manipulated signals with spectrum expansion based on pseudo-random sequences. The effect of synchronization errors when tracking the delay of a received phase-shift keyed signal with a spectrum extension based on pseudorandom sequences on the probability of tracking failure is studied. The calculation method is used to obtain families of dependences of the probability of tracking failure on the values of random and systematic components of the delay tracking error, normalized to the capture band of the time discriminator of the delay tracking scheme for various combinations of these parameters. The areas of weak and strong influence of the value of tracking errors over the delay of the received signal on the probability of tracking failure are determined. The nature of impact of random and systematic components of tracking error on the probability of failure of tracking was analyzed and it was found that in the General case is the ambiguity of normalized mean square of tracking error as the optimization criterion while minimizing the likelihood of tracking loss. Calculations performed for a wide range of changes in the normalized delay tracking errors show that to ensure a given quality of signal reception in a radio system with phase-shift keyed signals with spectrum expansion based on pseudorandom sequences, a joint choice of parameters of the delay tracking system that determine the value of random and systematic components of the tracking error is necessary. The results obtained can be used to analyze the characteristics of synchronization systems that monitor the parameters of received signals with a spectrum extension, and to justify the technical solutions of the synchronization system that provide the required quality of signal reception in information and measurement of radio-electronic systems.


2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
A.A. Paramonov ◽  
◽  
Zung Hoang Van ◽  

The method of transmitting information using broadband signals is recognized as an effective way to combat various types of organized intentional and unintentional interference. Among them, methods for transmitting digital information with frequency-hopping spread spectrum (FHSS) have found wide application. Due to its frequency and energy efficiency, the transmission method with frequency hopping is widely used in information transmission systems for various purposes, including military radio communication systems (RCS), where high interference immunity is required. Both when transmitting digital information under the conditions of the destructive effect of electronic suppression means, and without this effect, the received data sequence contains errors. To detect and correct them, noise-correcting coding is effective. The article considers the case when at the input of the receiver, in addition to its own noise, there is also a deliberate concentrated partial-band noise jamming, occupied by the RCS. An analysis is made of the noise immunity of a RCS with a frequency hopping and DBPSK with the combined use of error-correcting coding and time-frequency diversity of the code symbol. The application in the analyzed RCS of the algorithm of incoherent reception of diversity signals with weight processing and subsequent decoding is considered. It’s shown that the noise immunity of the RCS under the considered conditions turns out to be significantly higher than the RCS, in which the frequency diversity of the code symbol and the noise-immune coding are not used.


Author(s):  
A. V. Mazin ◽  
M. Yu. Aliyev

The article investigates the problem of providing high noise immunity radar under the influence of passive and intentional interference. The purpose of radio operation of the radar is to create conditions that would impede the operation of systems and minimize its effectiveness. The main method of radio transmission is still creating (staging) interference. Modern radar systems must solve the tasks in terms of electronic suppression using, including intentional interference and under severe time constraints. It is shown that the most effective way to improve the noise immunity of radar systems designed to operate in multipoint space, including non-stationary, interference is adaptive space-time processing of the received signals, based on the angular selection of targets, due to the formation of zeros in the directional diagram in the direction of interference sources. This problem is solved by determining the accuracy of the direction finding of interference sources and is achieved by the joint operation of the antenna array and multi-channel signal processing devices, namely the separation of interference signals on different receiving channels.


2020 ◽  
Vol 6 (3) ◽  
pp. 123-126
Author(s):  
Michael Unger ◽  
Johann Berger ◽  
Bjoern Gerold ◽  
Andreas Melzer

AbstractHigh intensity focused ultrasound is used as a surgical tool to treat completely non-invasively several diseases. Examples of clinical applications are uterine fibroids, prostate cancer, thyroid nodules, and varicose veins. Precise targeting is key for improving the treatment outcome. A method for an automated, robot-assisted tracking system was developed and evaluated. A wireless ultrasound scanner was used to acquire images of the target, in this case, a blood vessel. The active contour approach by Chan and Vese was used to segment and track while moving the scanner along the target structure with a collaborative robotic arm. The performance was assessed using a custom made Agar phantom. The mean tracking error, which is defined as the remaining distance of the lesion to the images’ centre line, was 0.27 mm ± 0.18 mm.


2010 ◽  
Vol 450 ◽  
pp. 552-555
Author(s):  
Ping Wang ◽  
Kai Xue ◽  
Qiu Hong Li

GPS attitude tracking system on the ship is a servo mechanism which could be used for counteracting the effects of the ship’s pitch and roll. But the attitude measurement precision of ship is more important to the tracking precision of the servo mechanism. As one of the major error sources, the noises of GPS attitude measurement bring out the steady tracking error of the tracking servo mechanism. To reduce the steady error due to the noise, the threshold noise removing method of wavelet is used to eliminate the noise. And the better result with the meaning of standard deviation and the better visual effects could be gotten by using the method. The signals of the processed high frequency and the retained low frequency could be reconstructed with the original signals. Therefore, the signals after noise removing could be obtained. The threshold noise removing method of wavelet used to remove the noise of GPS attitude information in the paper is of great value in practice.


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