Anti-interference Algorithm Research Articles

Linear Anti-interference Algorithm for Digital Signal Transmission in Fiber Optic Communication Networks based on Link Analysis

In order to achieve accurate transmission of protection signals in fiber optic communication networks, it is necessary to perform channel balancing configuration of fiber optic communication networks and adaptive forwarding control processing of relay protection signals, the author proposes an accurate transmission method for relay protection signals in fiber optic communication networks based on time-varying multipath fading suppression and adaptive beamforming. The system analyzes the sources of wireless long-distance pain signal interference signals, introduces anti-interference technologies such as two-dimensional joint processing (STAP), provides anti-interference algorithms and related gain analysis, and conducts signal processing gain simulation using MATLAB. Based on the analysis of comprehensive simulation results, at a given symbol length, the signal bandwidth increases, and the processing gain infinitely approaches the given theoretical limit value, rather than increasing nonlinearly. The reason is that the channel is affected by noise, and the channel estimation value and signal conjugate multiplication produce a noise quadratic term. At this point, the estimated value of the coherent region channel is reduced by the influence of noise, and the signal-to-noise ratio loss caused by the noise quadratic term is reduced, so the processing gain increases. During the process of infinite increase in signal bandwidth, the input signal-to-noise power ratio of the receiver tends to decrease towards an infinite value, limited by the size of the coherent region. The channel estimation value increases under the influence of noise, and the noise quadratic term is the main factor affecting the output noise power. When the symbol length is greater than the coherent time, the smaller the maximum Doppler frequency shift and the larger the coherent detection area, the greater the processing gain.

A heading correction technology based on magnetometer calibration and adaptive anti-interference algorithm

A heading correction technology based on magnetometer calibration and adaptive anti-interference algorithm

Multi-channel active noise reduction system realizes the local area sound field control of the subway driver's cabin

Aerodynamic noise, air conditioning fan noise, and wheel-rail noise during subway operation have an adverse effect on drivers' physical and emotional well-being and can jeopardize the safe operation of vehicles. On the basis of the original passive acoustic treatment, multi-channel active control technology is used to manage the local sound field in order to further enhance the acoustic comfort of subway drivers' working environment. The multi-channel active noise reduction system installed on the driver's seat is described in this paper. In order to properly prevent the issues of ear pain and obstruction brought on by prolonged use of noise-canceling headphones, the system integrates reference sensors, error sensors, speakers, and a power amplifier within the headrest. The noise in the carriage is picked up using a multi-channel reference signal, and a low delay and anti-interference algorithm is investigated in accordance with the wide frequency band's characteristics and the abrupt change in sound pressure level when the vehicle is running. The test results demonstrate the system's ability to stabilize under situations of abrupt changes in driving noise and in-car broadcast, as well as to successfully minimize noise in the head area of subway drivers.

Inter-symbol Anti-interference Algorithm for 5G Communication System Based on Deep Learning

As a matter of fact, the fifth generation (5G) wireless technology requires huge capacity to ensure normal use of communications, and a large amount of data will cause interference between wireless communication systems. With this in mind, to reduce inter-symbol interference in wireless systems, MIMO-OFDM is employed, the rapid growth of deep learning has the potential to significantly enhance wireless system performance. In reality, applying deep learning to estimate channels in MIMO-OFDM systems can reduce channel errors as well as improve channel quality, thereby greatly reducing inter-code interference between systems. On this basis, this paper introduces various DL-based channel estimation and demonstrates its improvement in the efficiency of the system. According to the analysis, the usage of deep learning in 5G wireless communication systems has great advantages. In addition, the limitations and defects are also discussed at the same time. Overall, these results shed light on guiding further exploration of 5G communication.

A new blind anti‐jamming algorithm based on a novel antenna array design

The next-generation navigation tools are developed to enable precision and reliability. Military users are more likely to encounter jamming, so it is necessary to seek the technologies which can steadily provide high-precision positioning services in all-weather and harsh conditions. However, when users use an array antenna for interference suppression, it usually introduces pseudorange and carrier phase biases, which deteriorates the accuracy and integrity of positioning. To address this issue, the authors propose a blind anti-interference algorithm with biases suppression. Compared to the commonly used blind space–time adaptive anti-jamming algorithms, this algorithm can not only retain the advantages of the simple structure of the blind anti-jamming algorithm but also suppress pseudorange biases and carrier phase biases, both of which are crucial for users to obtain the availability of positioning. Moreover, the algorithm proposed can be applied easily and quickly to the actual high-precision positioning system with minor hardware changes in some cases. The relevant theoretical analysis and experiments have proved the effectiveness of the proposed algorithm: (1) code phase biases and carrier phase biases can almost be ignored and (2) it also can significantly improve the accuracy and integrity of positioning; the average positioning error is 1.6 mm, and it can keep the positioning accuracy better than 0.1 m for 97.5% of the time.

Dance Movement Interference Suppression Algorithm Based upon Contour Model and AdaBoost Algorithm

With the development of computer technology, digital image processing, as an emerging field, has become an indispensable tool in the information society. The action interference effect refers to the phenomenon that an individual reacts to a dangerous object longer than a safe object in the state of preparation for action. Currently, there is no effective anti-jamming technology to recognize dance movements. In order to solve these problems, this paper proposes a dance movement interference suppression algorithm based on contour model and AdaBoost algorithm, which aims to realize the application of gesture-based behavior recognition technology in the field of dance steps and complete the recognition of some dance steps. The method of this paper is to study the contour model based on the image and then propose to use the AdaBoost algorithm to detect body movements and finally use the radio frequency interference suppression algorithm to ensure the smooth operation of the technology. The function of the method is to propose a dance action recognition and anti-interference algorithm based on contour model and AdaBoost algorithm. This article describes the contour model and then uses the AdaBoost algorithm to recognize the action and adjust the action interference effect. The results show that the algorithm proposed in this paper can accurately identify dance movements, with an average recognition accuracy rate of 99.2%.

Dynamic Channel Allocation Algorithm for Heterogeneous Cellular Networks in Power Communication

In order to solve the problems of low efficiency and high noise in the application of modern channel resource allocation methods, an anti-interference dynamic channel allocation algorithm for heterogeneous cellular networks in power communication is proposed. First, the heterogeneous cellular network model of power communication and the architecture of power multi-channel transmission platform are constructed. Then, according to the receiving and noise characteristics of communication resources, the anti-interference algorithm of power communication resources under multi-channel transmission is designed to obtain the communication index of power communication heterogeneous cellular network, and the anti-interference dynamic allocation algorithm of power communication heterogeneous cellular network resources is realized, Finally, the comparison method is used to prove the practicability of the method in this paper. The experimental results show that the average value of communication resources after interference suppression is 950 Mb, the average signal to noise ratio is 10.5 dB, and the resource allocation time is less than 3 min after 5000 iterations, which is superior to the comparison method. The method has good channel anti-interference ability and channel resource allocation efficiency, and has certain application value.

Distributed collaboration and anti-interference optimization in edge computing for IoT

The edge computing (EC) systems for Internet of Things (IoT) can bring out low latency, high reliability, distributed intelligence, and network bandwidth savings to industrial real-time applications. However, limited computing and processing capabilities of edge devices remains to be difficult to meet complex data processing and artificial intelligence (AI) analysis requirements for diverse services. Besides, the scarcity of wireless spectrum resources in harsh industrial environment makes the interference between devices more serious. To address these challenges, this paper proposes an adaptive distributed collaborative anti-interference optimization scheme for IoT-edge system. Firstly, the EC system model is established, and the model of link failure probability is derived theoretically. Then, an Occupy-Interference Mitigation (O-IM) algorithm based on full-frequency multiplexing is proposed. The algorithm combines adaptive full-frequency multiplexing and interference mitigation to reduce the dependence of the reliable collaboration on bandwidth and signal-to-noise ratio (SNR). In addition, an anti-interference algorithm based on Interference Mitigation and inter-cellfrequency multiplexing Interference Avoidance (IM-IA) is proposed to balance bandwidth and SNR. This algorithm adopts interference cancellation scheme in the broadcasting phase, and adopts orthogonal frequency division in the collaboration phase. Extensive simulation results on Mininet platform verify that the proposals can obtain lower failure probability, and are less than traditional solutions in transmitting power, bandwidth, and SNR requirements. Moreover, the O-IM is suitable for low power scenarios, while the IM-IA is more suitable for high power case.

Recent Advances on Anti-interference Control Strategies for Better Operation

Background: Under the influence of complex external environment and the internal parameter perturbation of the system itself, many interference problems hinder the development of the controlled object according to the predetermined trajectory. Objective: The objective of this study is to provide the corresponding anti-interference control methods for different degrees of interference and introduce their respective characteristics. Methods: This paper mainly summarizes the application examples of anti-interference control algorithms in the face of different interference problems, which are mainly divided into three categories. Especially two new concepts, whose names are composite anti-interference control and innovative anti-interference control algorithm design, are presented. At the same time, this paper not only summarizes the outstanding contribution of anti-interference control in the mechanical field, but also expounds on the application examples of coupling of anti-interference control in electrical aspect and describes the application of anti-interference control in other planets. Results: From the interference problem on the earth to the anti-interference control of outer space, the control algorithm shows the unique charm step by step. In the future, to cope with the complex and changeable environment, the anti-interference algorithm will continue to be optimized in depth, letting the control system run steadily in direction of fast, accurate and stable on the expected track. Conclusion: Anti-interference control plays an important practical role in the control of systems. Whether in the mechanical field or coupling in other aspects such as electrical, it can help the system run better according to the needs of the controller. It is effective and reasonable to combine different strategies for the systems, so that the systems are more accurate and stable.

Research on Anti-interference Control of Hydrostatic Guide Rail's Oil Film Thickness

With the rapid development of modern manufacturing technology, people have higher and higher requirements for the quality of mechanical products, and the precision of machine tools for processing mechanical products has gradually increased. Therefore, the development of static pressure guides is particularly important for precision processing industries. The load on the guide rail has an important effect on the thickness of the oil film, and the stability of the oil film thickness directly determines the accuracy of processing. In order to obtain the best control method for the thickness of the oil film, the dimensions of the hydrostatic guide rails and the three-dimensional model of the guide rails were designed and calculated in this paper, and the fuel supply method of the guide rails was determined. The simulation model of the oil film was established and imported from the AMESim software into the FLUENT software to obtain the pressure, velocity, and temperature distribution maps of the oil film. And the pressure distribution data was processed after summarizing. Combined with the relevant mathematical models, the mathematical model of the oil film thickness was finally obtained. Then the Simulink software was used to analyze and the PID control was introduced for comparative analysis. The DOB anti-interference control theory was introduced, and the anti-interference control algorithm was improved. The anti-interference algorithm adapted to the oil film thickness control complete the programming of the modules of the interference controller. The anti-interference control section was created in the Simulink software, and the system of the DOB module was finally completed after packaging. In order to verify the method in t his paper, a static pressure rail test bench was set up, and relevant detection tests were completed. The results of the above studies showed that the control performance was greatly improved after introducing the anti-interference algorithm adapted to the oil film control system.

Anti-interference Algorithm for Broadband Wireless Communication based on Embedded Microcontroller

In order to improve the reliability of broadband wireless communication, the anti-interference design of broadband wireless communication in embedded environment is carried out, and an anti-interference algorithm of broadband wireless communication based on embedded microcontroller is proposed. The hardware of the anti-interference device is mainly composed of the communication modulating module, ARM main control system module and the single chip microcomputer main control module. The anti-interference algorithm is designed by using inter-symbol interference suppression algorithm, and the data transmission channel distribution model of broadband wireless communication is constructed. The interference filtering of broadband wireless communication is based on the decision feedback equalization method. The simulation results show that the anti-interference design of broadband wireless communication using this method has strong anti-interference ability, the output SNR is higher than that of the traditional method, and the communication quality is improved.

Phase analysis and error compensation of anti-jamming nulling algorithm for satellite navigation array antenna

The traditional adaptive nulling antenna array anti-interference algorithm can cause phase distortion, make the antenna phase unstable, and produce positioning error. Based on the analysis of the adaptive nulling antenna array anti-jamming algorithm, this article deduces the calculation method of its phase centre and the stage of real-time change, determines the phase centre error, and calculates the compensation value which can be used for the repositioning after correction. Simulation and experimental results verify the rationality and effectiveness of the algorithm, which can be used to improve the positioning accuracy of anti-jamming array antenna GNSS receiver.

Detection and tracking of pigs in natural environments based on video analysis

Detection and tracking of pigs are important for analyzing pig behavior using computer vision. However, in natural environments, illumination changes, complex scenes, adhesion, occlusion, and individual identification from multiple objects are challenges for detection and tracking. This paper provided an anti-interference algorithm for pig detection and tracking based on video analysis. Firstly, pigs were recognized in natural environment based on color information, and noises were removed based on the analysis of connected regions in the binary images. Secondly, multiple pigs were separated by contours and edges. Thirdly, pigs were tracked based on a set of association rules with constraint items (DT-ACR). When DT-ACR fails, targets that are not lost were tracked continuously, while lost targets were retrieved in the nearby location, which effectively increased the duration of tracking. Experiments showed that the algorithm was able to track each individual pig in the following conditions: no-light scenes, sun glint scenes, adhesion scenes and occlusion scenes. The overall tracking accuracy reached up to 87.32% (83.85% for serious adhesion, 87.4% for occlusion, 82.4% for strong light, 82.17% for no light and dark, 96.58% for 2 pigs, 88.33% for 3 pigs and 77.63 for 4 pigs). A pig activity analysis study based on the pig detection and tracking algorithm was carried out, and the results showed that the proposed method was able to track pigs for a long period of time and extract the values that reflected pigs’ movements. Keywords: computer vision, pigs, animal behaviors, tracking, detection DOI: 10.25165/j.ijabe.20191204.4591 Citation: Xiao D Q, Feng A J, Liu J. Detection and tracking of pigs in natural environments based on video analysis. Int J Agric & Biol Eng, 2019; 12(4): 116–126.

A Space-time Anti-interference Algorithm Based on Antenna Rotation

To inhibit interference, the conventional space-time adaptive processing technology can form nulling at both the interference coming angle and the interference frequency, inhibiting the interference in the development of satellite navigation anti-jamming technology. When the frequency of the signal source is equal or similar to the central frequency of the interference source and they are adjacent in the spatial domain, the desired signal will be suppressed in the traditional algorithms, which will lead to the decrease of the output signal-to-interference-noise ratio (SINR).To overcome this issue, a space-time joint anti-interference algorithm based on planar array steering is proposed in this paper. Specifically, the plane array steering is adjusted by calculating the spatial correlation coefficient of the desired signal and the interference signal. Simulation results show that the proposed algorithm can increase the output SINR by about 10dB under the same frequency, and the anti-interference ability of the system is enhanced.

Detection and tracking of pigs in natural environments based on video analysis

Detection and tracking of pigs are important for analyzing pig behavior using computer vision. However, in natural environments, illumination changes, complex scenes, adhesion, occlusion, and individual identification from multiple objects are challenges for detection and tracking. This paper provided an anti-interference algorithm for pig detection and tracking based on video analysis. Firstly, pigs were recognized in natural environment based on color information, and noises were removed based on the analysis of connected regions in the binary images. Secondly, multiple pigs were separated by contours and edges. Thirdly, pigs were tracked based on a set of association rules with constraint items (DT-ACR). When DT-ACR fails, targets that are not lost were tracked continuously, while lost targets were retrieved in the nearby location, which effectively increased the duration of tracking. Experiments showed that the algorithm was able to track each individual pig in the following conditions: no-light scenes, sun glint scenes, adhesion scenes and occlusion scenes. The overall tracking accuracy reached up to 87.32% (83.85% for serious adhesion, 87.4% for occlusion, 82.4% for strong light, 82.17% for no light and dark, 96.58% for 2 pigs, 88.33% for 3 pigs and 77.63 for 4 pigs). A pig activity analysis study based on the pig detection and tracking algorithm was carried out, and the results showed that the proposed method was able to track pigs for a long period of time and extract the values that reflected pigs’ movements. Keywords: computer vision, pigs, animal behaviors, tracking, detection DOI: 10.25165/j.ijabe.20191204.4591 Citation: Xiao D Q, Feng A J, Liu J. Detection and tracking of pigs in natural environments based on video analysis. Int J Agric & Biol Eng, 2019; 12(4): 116–126.

A Strong Interference Suppressor for Satellite Signals in GNSS Receivers

In this paper, we discuss a method to protect satellite signals from strong time-varying interferers. Time-domain, transform-domain, and space-domain algorithms have been widely used for interference suppression. However, when used under high dynamic conditions, these methods cause serious suppression of satellite signals in the GPS receivers along with inhibiting interferers. To address this problem, we optimize the satellite and interference steering vectors using a multi-star forming approach to distinguish satellite signals and strong interferers. In order to detect time-varying interferers, we further introduce a novel hidden Markov model (HMM), and power inversion (PI) and Multi-star interference suppressed (Multi-PI) model anti-interference synthesis scheme.A bank of HMM filters are operated to track the on–off interferers in the frequency domain, and decide if an anti-interference algorithm needs to be used. After HMM, the Multi-PI algorithm is implemented to inhibit broadband interferers. The experimental results show that our novel scheme adapts quickly when tracking time-varying interferers and protects GPS signals from losses.

A novel adaptive anti-interference algorithm based on negative diagonal loading for spoofing and jamming in Global Navigation Satellite System

Spoofing and jamming are two kinds of significant interferences in Global Navigation Satellite System (GNSS). When they coexist in GNSS propagation environment, interference suppression becomes more difficult. Conventional power inversion (PI) algorithm can reject jamming effectively, but has different influences on repeat spoofing when the different numbers of elements are used in an antenna array. Nevertheless, repeat spoofing still has the capability of deception after being processed by the PI algorithm. In the paper, different influences have been analyzed and a blind adaptive anti-interference algorithm is proposed based on negative diagonal loading technique. The proposed method can adaptively reject spoofing and jamming simultaneously without estimating the direction-of-arrivals (DOAs) of them, and ensure that authentic satellite signal can be acquired by the GNSS receiver without other treatment of repeat spoofing. Simulation results show the effectiveness of the new method.

An Algorithm for GPS Anti-Jamming Based on Improved Fast ICA

In the practical environment, it is difficult for the user receiver to get DOA information of GPS signals in advance. In this paper, on the basis of blind source separation (BSS) theory, a signal-separation-based GPS anti- interference algorithm is proposed. In accordance with BSS process modes, wavelet denoising algorithm is first adopted to restrain the influence of noise on separation algorithm. Then, improved FastICA separation algorithm is adopted to separate the mixed signals. Finally, secondary wavelet denoising algorithm is used to restrain the amplified noise and GPS signal anti-interference is realized. The test shows that: the anti-interference algorithm proposed in this paper is effective. Under the same SNR, the algorithm has better anti-interference effect than traditional separation.

Error Analysis and Algorithm Validation of Geomagnetic Sensor

Based on the fundamental principle of magnetic compass, the effect of interference and sensor errors on the magnetic azimuth measurement accuracy are analyzed. In order to eliminate the influence of geomagnetic sensor system error interference sources effectively, the paper puts forward a method of obtaining accurate heading angle and azimuth of magnetic compass, which is realized by converting magnetic components in the space coordinates to horizontal coordinate as well as adding an algorithm of eliminating carrier interference and software filter. The test of application system shows that data errors are greatly reduced after adding the anti-interference algorithm. The system testing errors is almost equal with Xiaomi phone at the same condition. It proves that this system is applicable to general navigation field.

A High-Precision and Low-Cost Planar Array Signal Simulator Based on Cable Delays

For common planar array in Global Navigation Satellite System (GNSS) receivers, effective array signal simulation requires high-precision control of time delays and is very sensitive to errors. Typical array time delay range is about 0 ~ 0.6 ns. The resolution and accuracy needed for time delay controlling is within 0.005 ns. Such rigorous specifications make array simulation quite difficult. Common techniques always need the collaboration of a large number of hardware equipments, which are costly and complicated and therefore limited to widespread applications. This letter presents a planar array signal simulator based on cable delays, which is less expensive, easy to implement, and high-precision. However, electromagnetic waves propagate at a relatively lower velocity in transmission lines than in air, which may result in large errors and problems in designing of the array wavefront simulator. In this letter, the velocity difference and its influence mechanism on array simulator design were analyzed deeply. On this basis, errors introduced by propagation velocity difference were calibrated, which effectively improved the accuracy of array signal simulators based on cable delays. Experimental results show that the direction-of-arrival (DOA) simulation accuracy is better than 5 °. The technique can be utilized in the research of adaptive antenna array anti-interference algorithm.