The existing test method for properties of UAV data-link is usually the actual flight test or field "distance" test, which has long test cycle and difficulty for the extraction of test data. In view of this situation, we in this work adopted the data-link semi-physical simulation test platform based on darkroom calibrate-link method, establishing and analyzing the space natural decline model, atmospheric environment model, and aircraft attitude angle model that affecting the transmitting and receiving of signals. Meanwhile, the average delay from-terminal-to-terminal and the fluctuation of the average delay of the UAV under different MAC channel access protocols are discussed using the darkroom calibrate-link method. In order to improve the response characteristics of the UAV, time delay is compensated using optimal control methods, and the effectiveness of the compensation method is validated based on and the platform we built. The simulation results show that, the design of UAV data-link can be calculated by this theory, and the introduction of the optimal control method significantly improves the dynamic response characteristics of the UAV.
In this paper, we conduct research on the Android framework smart watches from the data security point of view. With the speeding development of smart watches, Android smart watches the operating system is more and more attention by people and use, data security has become the user's concern problem, this article through to the Android system expatiates on that the various security mechanisms, and for different security mechanisms to provide the solution and hope to provide a little help developers improve Android system security. The scheme improves the Android data security, realizes the Android data encryption and authentication, ensures the confidentiality and integrity of the sensitive data, as well as resistance to deny as to the further popularization of the Android system provides a safety basis that is meaningful.
During the course of studying how to improve and optimize the anti-jamming ability of the satellite navigation and positioning system, the satellite channel was faced with many types of jamming signals. It is difficult to adopt one kind of jamming suppression technology to effectively suppress all kinds of jamming. In order to solve these problems, a new anti-jamming architecture for satellite navigation and positioning system is proposed. That is adopting the jamming cognitive method combined with the time-frequency domain jamming type recognition, power analysis and jamming DOA estimation. Also, the anti-jamming architecture design of the satellite navigation and positioning system is given based on the jamming cognition. Theoretical analysis and simulation results show that the anti-jamming architecture can detect the different jamming signals according to different jamming types, simplify the jamming suppression algorithm, grade and classify to suppress jamming signals.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.