With the continuous advancement of high-density space launch missions, the vibration phenomenon generated during launch has gradually attracted attention. Research has found that most of these vibrations can have varying degrees of impact on towers and satellite rocket bodies. This paper proposes a vibration measurement method based on domestic Microelectromechanical System (MEMS) acceleration sensors for vibration characteristics related to structural mechanics such as large vibration impact, wide spectrum range, and low amplitude and frequency of vibration signals in the active section of the rocket launch during the actual launch process of a certain satellite launch site. This method is used for real time acceleration detection of X-axis, Y-axis, and Z-axis vibrations, uses MEMS sensors to collect vibration signals, completes the display of acceleration amplitude through a series of processes such as low-pass filtering, analog-to-digital A/D conversion, data acquisition and analysis. And through software simulation and hardware circuit testing, the feasibility of the scheme design and the reliability of the vibration measurement system were verified, providing solutions and technical support for the subsequent development and transformation of the launch site.
In the field of metrology, the general instrument installed in enterprises and institutions is often accompanied by the mandatory verification of the established period, but its working health is unknown. This paper carries out the health status research of general instrument based on the common two-norm form in engineering applied mathematics, uses the unilateral construction test algorithm to analyze the data samples of typical equipment pressure gauge and verify the algorithm ability, and provides a complete implementation method for the health status evaluation of general instrument in service.
KEYWORDS: Local area networks, Design and modelling, Network security, Data transmission, Databases, Computer security, Telecommunication networks, Information security, Data storage, Control systems
In order to ensure the normal operation of the local area network (LAN), maintain the stability, accuracy and security of data transmission, it is necessary to monitor its lines in real time. Aiming at the current LAN network management without line interruption automatic monitoring function, a LAN line interruption monitoring module is designed. It realizes automatic monitoring of line interruption and timely alarm. The functional requirements of the LAN line interrupt monitoring module are analyzed in this paper. The design concept, implementation process, registration client, database, page, security policy and other design processes of the LAN line interrupt monitoring module are introduced in detail. The application and validation are given. It can be seen through the application that the module has good practical application value. It has important practical significance and guidance for network managers.
Segment the rocket target from the live image has a wide range of application scenarios in the space launch. Aiming at the problem of determining the optimal threshold in the traditional image segmentation, this paper proposed a method to determine the optimal threshold and then carry out image segmentation based on genetic algorithm. And the image segmentation result obviously enhanced, but there are many judgment and large amount of code, which need to be further optimized in the follow-up research.
KEYWORDS: Vibration, Transportation, Space operations, Data acquisition, Roads, Signal processing, Sensors, Design and modelling, Data storage, Tunable filters
Spacecraft will suffer some degree of vibration and shock when transported by road, it will bring the security and stability risks to the spacecraft’s internal structure. In this paper, based on the study of the vibration and shock sources of spacecraft’s road transportation, the vibration characteristics of road transportation at the launch site are analyzed, and a road transportation monitoring system is designed and developed by using virtual instrument technology. By collecting acceleration signals during transportation and using FFT technology to process and analyze signals, the system realizes real-time monitoring of the vibration of the spacecraft transportation process. Now the system is built and put into use to meet the measurement requirements and has great significance for ensuring the safety of spacecraft during transportation.
The use of space-based surveillance systems to implement long-distance, high-precision detection and imaging of space targets is of great significance for mastering space activities. The basic principles of laser reflection tomography are introduced. For the spin-stabilized satellite target, the parameter index of the space target laser active detection system is designed, and the orbit of the imaging satellite and the target satellite are designed. The satellite is obtained by constructing a three-dimensional model of the satellite. Target multi-angle laser echo, and then use different image reconstruction algorithms to achieve satellite target laser reflection tomography, which can provide a reference for the design of laser active imaging system.
The semantic segmentation technology of remote sensing image refers to labeling the semantic information of pixel-level of the image to complete the classification, namely, terrain classification. It is widely used in intelligent maps, smart cities and other aspects. With the increase of satellite image resolution and the development video communication moonlet, its application and scenes are greatly broadened. The traditional remote sensing image semantic segmentation method mainly uses statistical machine learning methods, which cannot take into account the spectral features and the context semantic relationship of pixels, and has a bottleneck in improving the accuracy of classification. In deep learning method, Using the convolutional neural networks to extract features can achieve classification results of remote sensing images with higher classification accuracy. Aiming at the problems of existing deep learning methods in multi-spectral image semantic segmentation, to make full use of the information of multi-spectral images, this paper proposes a semantic segmentation algorithm for multispectral remote sensing images based on deep learning and verified the method on open data sets.
During initial target tracking by radar, the sighting telescope is usually used to guide the antenna to achieve the initial target intercept. When the radar changes from the guidance state of the sighting telescope to the self-tracking state of radar, it’s easy to lose the target due to the inconsistency between the movement direction of radar antenna and that of target. To solve this problem, a regenerated feedback compensation control strategy is proposed based on speed memory extrapolation and compensation timing selection in this paper. By loading the algorithm into the real equipment and tracking the Unmanned Aerial Vehicle, it’s verified that the method can achieve the stable tracking of the target at a faster speed.
With the gradual improvement of space launch sites image communication system construction, Visual command is increasingly demanding video image retrieval. The previous keyword retrieval method can not meet the requirements of new generation space mission network communication, content-based retrieval need to be developed. In view of the problem that video information is unstructured and cannot be quickly previewed, this paper studies the video key frame extraction algorithm and propose a video key frame extraction algorithm based on convolutional neural network.
KEYWORDS: Autoregressive models, Data modeling, Local area networks, Analytical research, Error analysis, Mathematical modeling, Network security, Process modeling, Time series analysis, MATLAB
The characteristics of the ARMA model are analyzed according to the characteristics of the short-term flow data of the local area network in this paper. The time prediction model of network flow is established on the ARMA method. The prediction parameters of the ARMA model are determined and the model is simulated According to the short-term flow prediction. The comparison between the simulation results and the measured data of NetFlow shows that the model can accurately predict the short-term flow behavior trend of the local area network, which can provide reference and reference for the analysis of network traffic behavior.
Electrostatic potential testing is an important parameter for characterization of the electrostatic source. A non-contact electrostatic potential test device is designed for zreo-point drift, interference effect, narrow frequency range and other common problems in the current non-contact electrostatic potential test device in this paper. The above problems such as zreo-point drift, interference effect and narrow frequency range are solved. The basic principle of non-contact electrostatic potential test is introduced. The hardware and software design and implementation process of non-contact electrostatic potential test device are described in detail. The test verification and application of the device are given. Finally the key technical problems solved in the design implementation process are summarized.
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