Journals
  Publication Years
  Keywords
Search within results Open Search
Please wait a minute...
For Selected: Toggle Thumbnails
Analysis of Double Overlapping Signals and Improvement of IFM System
WANG Hong-xun, WANG Lian-he, WANG Jian, WANG Shi-yan, WANG Hong-lei
Modern Defense Technology    2021, 49 (2): 64-71.   DOI: 10.3969/j.issn.1009-086x.2021.02.010
Abstract256)      PDF (3444KB)(587)       Save
RWR (radar-warning receiver)/ESM (electronic warfare support measure) system usually uses traditional instantaneous frequency measure (IFM) technology to detect the frequency of signals in real time,but it can only estimate one frequency when it receives overlapping signals,and easily create frequency measurement errors.But in complex electromagnetic environment of the modern battle,pulses overlapping probability increase.So analyzing the influence of overlapping signals to IFM system is particularly important.Through the basic principle of IFM,analyzed each node response of IFM microwave phase discriminator in the case of double overlapping signals,built mathematical model of output UI,UQ and put forward a new algorithm—UI,UQ calculation algorithm that can estimate the frequency of double overlapping signals.Simulation results show that the algorithm can estimate the frequency of overlapping signals and keep advantages of original IFM.
Reference | Related Articles | Metrics
Some Thoughts on Deep Space Safety in Future
WU Li-jun, WANG Xu, WANG Jian-bin
Modern Defense Technology    2021, 49 (2): 8-12.   DOI: 10.3969/j.issn.1009-086x.2021.02.002
Abstract262)      PDF (599KB)(682)       Save
The strategic worth of deep space is commonly concerned and regarded by international society,every aerospace great power is quickening the development of deep space activity.As a new and important strategic field,the security problem of deep space can not be evited.Problems confronted by the security of deep space are thinked from international politics、developing stratagem、science and technology、militarization、environment abnormity and asteroid,hope to promote the research in security of deep space.
Reference | Related Articles | Metrics
Understanding and Thinking about Security Issues of Deep Sea
WU Li-jun, HU Jian-hang, WANG Xu, WANG Jian-bin
Modern Defense Technology    2021, 49 (1): 27-31.   DOI: 10.3969/j.issn.1009-086x.2021.01.004
Abstract3374)      PDF (781KB)(1814)       Save
Carrying out holistic concept of National security need to concern security not only from traditional field,but also from jumped up field.As a jumped-up and strategic field,researching security of Deep sea have great significance.From the viewpoint of security research,several problems which are valuable to be regarded during the course of Deep sea exploitation are considered.It is hoped to support the research of security,and attract more people to concern Deep sea security and promoted the development of Deep sea exploitation and security more harmoniously.
Reference | Related Articles | Metrics
Rocket Connector Auto-Docking System Detection Based on Machine Vision
WANG Jian-bo, CHEN Yu, BAI Huan-xu, ZHANG Tao-yuan, QIE Xiao-bin
Modern Defense Technology    2018, 46 (4): 79-85.   DOI: 10.3969/j.issn.1009-086x.2018.04.013
Abstract227)            Save
The automatic docking process of connector and rocket valve is studied, and a bias measurement system based on dynamic azimuth detection alignment technique is proposed. The deviation value of the connector with the fill valve is obtained and defined as the initial value. The image of the cooperative target is obtained by the optical camera. The camera pose in the two-dimensional plane is quickly extracted by identifying the direction of the target image and the marker size; and the laser sensors are used to accurately obtain the distance information between the target and the camera. The deviation value between the connector and the fill valve can be obtained in real time through this measurement system. It is applied to the automatic docking system, and the results show that the method meets the technical requirements of the automatic docking displacement accuracy 1 mm of the rocket.
Reference | Related Articles | Metrics
SINS/Odometer Integrated Navigation Based on Strong Tracking Filter
CHEN Yu, WANG Jian-bo, ZHANG Ling-dong, CAO Quan, CHEN Shi-ye, LIU Yu-hang
Modern Defense Technology    2018, 46 (4): 27-32.   DOI: 10.3969/j.issn.1009-086x.2018.04.005
Abstract287)            Save
Aiming at the problem that the vehicle odometer scale factor changes in real time due to the influence of tire pressure and temperature, a method of SINS (strap down inertial navigation system)/odometer integrated navigation based on strong tracking filter is presented. The property that the residual sequences of Kalman filter are mutually orthogonal is used to adjust fading factor adaptively. The strong tracking filter has the ability to track the sudden change state. The average velocity matching method is proposed to eliminate the influence of vehicle vibration and odometer quantization error on integrated navigation. The lever arm error is adopted into the state variables to eliminate the influence of inaccurate lever arm on integrated navigation when the vehicle is turning. The SINS/odometer integrated navigation model is built. The actual vehicle integrated navigation experiment is carried out. The results show that the positioning accuracy of integrated navigation is better than 1‰D.
Reference | Related Articles | Metrics