With the development of science and technology, DOA estimation technology has became one of the research hot spots. typical MUSIC algorithms are widely used in DOA estimation.its applicable scope is the common navigation system. In order to improve the resolution of the MUSIC algorithm and the accuracy of DOA algorithms, reduce the error of channel in the actual situation, this article presents an algorithm for DOA estimation of interference signals from satellite navigation that considering channel errors of array antenna based on the principle and characteristics of the classical MUSIC algorithm, and simulated analysis for MUSIC space spectrum under different channel errors and error compensation, the simulation results show that this algorithm can reduce the error caused by the inconsistency of signal channels. when the resolution of the MUSIC algorithm is improved. This article has certain research significance to the application of MUSIC algorithm in the actual situation.
WT5BZ]:One job for theorists now is to improve social education and lead society to coordination. This paper analyzed the difficulties, problems and their solutions with date from investigation from the perspective of sociology.[WT5HZ]
GNSS is now affecting in various aspects of human life, while it is susceptible to interference including jamming and spoofing, which will make itself be caught in serious risk. Therefore, reliable safeguards are urgently necessary to ensure the safety of GNSS applications. Array signals received by different array sensors contain the spatial characteristics of GNSS signals from different directions, which offer possible approaches to spoofing mitigation based on the general assumption that all spoofing pseudorandom noises are from the same direction. Given this, a novel array signal processing method is proposed in this paper, which can adaptively suppress jamming and spoofing and enhance the useful signals simultaneously. This proposed method can be compatible with the traditional GPS receiver without the need of adjusting the GPS receiver hardware. The effectiveness of this proposed method is verified by simulation results.
In his whole life,Liang Qi chao kept on tracing the anlogy between Chinese culture and western culture, which, on one hand, could be considered as a propaganda way of modern scholar in the communication and mergence of Chinese and western culture; on the other hand, proved the common spirit of human culture. But the comparison between the two cultures couldn't transmit the spirit of western culture and blurred the essential difference of Chinese and western culture in many sides concerned.
Current research on the interference of GNSS (Global Navigation Satellite System) array antennas focuses on the single interference effect and the improvement of interference hardware capability, while the multi-degree-of-freedom (DOF) interference model and mechanism remain to be fully studied. Aiming at this problem, this paper analyzes the preconditions for the definition of anti-jamming degrees of freedom and the characteristics of super-DOF interference through formula derivation and simulation. First, by analyzing the influence of the number of interfering signals on the angular resolution, the prerequisite of the definition of anti-interference degrees of freedom in the airspace is proposed. Second, the definition of anti-interference degrees of freedom is used to calculate the change rule of the critical power of the interference under different numbers of interfering signals. Finally, the influence of super-DOF interference on the array antenna is analyzed. The results show that the prerequisite for the anti-interference freedom of the array antenna is that the distribution interval of the interfering signal is greater than 15°, taking a four-array element uniform circular array antenna as an example. The critical interference power of the array antenna decreases by about 15 dB when the number of interfering signals exceeds the degrees of freedom of the array antenna’s interference immunity, provided that the interference resolution is satisfied. The conclusions of this paper give the critical power change rule of multi-DOF interference and the effect of super-DOF interference, as well as the prerequisites for the setting of interference signals, which can be used, for example, in the deployment of distributed interference sources and the development of anti-jamming algorithms.
It is the non - public economy there are the two major function in the present stage: Push the development of the social productivity; The influence is together realizing of wealthy target. These two major function exsits on the function's results important difference,Want to distribute to flick the function of the socialism system, promote the non - public economy health development, and realize completely developments middle -class family struggling of society target.
Deng Xiaoping's socialist essence theory has profuse and profound content. This dissertation is about to discuss the theory on common prosperity by Deng Xianping in order of development target and development shortcut and to dispose of the relation to be well managed as to pre-post development and coordinated development in the process of achieving common prosperitv.
It's a realistic difficult problem about how to improve the positioning accuracy and the reliability of RAIM algorithms, on the situation that there are not enough available satellites. This dissertation puts forward RAIM algorithms with the elevation information in the areas as marine navigation. Through this method, the information redundancy can be increased. With only 3 satellites, we can realize positioning calculating. With 5 satellites, we can identify one-faulty satellite. With 6 satellites, we can identify simultaneous two-faulty satellites. According to the simulation analysis, this method can effectively improve the availability of fault detection of RAIM algorithms for one-faulty satellite and two-faulty satellites. In practice, it has profound guiding significance for the improvement of the positioning accuracy and the reliability of the receiver.
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