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For long-distance transmissions, relay-aided transmission technique is a promising solution to improve the performance for the free-space optical (FSO) communications. In this paper, a serial decode-and-forward relay-aided FSO communication system is considered. In the system, the main noise is Gaussian noise, however, with a noise variance depending on the current signal strength. Moreover, a composite...
This paper presents the pilot-induced oscillation (PIO) problem in the airdrop stage, analyzes the main causes of the PIO in the drop stage, establishes the closed-loop system with the actuator rate limit, and deduces the PIO formula of closed loop system. Based on the synchronization and Neal-Smith pilot model and the different actuator saturation values, the descriptive function method and the GAP...
With the development of global navigation satellite system (GNSS) remote sensing, radio occultation (RO) has become an important atmospheric observation technique that mainly be used for numerical weather prediction (NWP) and global climate monitoring (GCM). However, residual ionopheric error (RIE) can still be significant after an ionospheric error elimination by linear combination of dual-frequency...
GNOS (GNSS Occultation Sounder) is an instrument developed by National Space Science Center (NSSC), Chinese Academy of Sciences. It was first successfully launched in September 23, 2013, as a payload of FY3C. More than 700 occultation events were received every day. The modified GNOS will also be on-board the FY3D satellite scheduled to launch in 2016. It contains three major improvements including...
This paper presents the error characteristics of MSISE-90, and data analysis is performed using statistical comparison. In this experiment, the absolute error, root mean square error and standard deviation of temperature and pressure for each month, latitude and geometric height are calculated, and the curve of annual global error characteristics is obtained at the same time. The result shows that...
The required time of aircraft turnaround support activity directly affects the aircraft combat effectiveness. Aiming at the problem that the shortest time of support activity is hard to realize under the limited aircraft support resources conditions, the time optimization algorithm based on Branch and Cut Method (BCM) of the aircraft turnaround support activity is given in this paper. The purpose...
The serious impact of volcanic eruption to aviation and the long term climate have gained widely public attention in recently years. China's meteorological satellites (Fengyun series) have gradually become an integral part of the global satellite observation system and also provide a new data source for monitoring global volcanic eruption. In this work, recent researches and applications about volcanic...
Forest biomass is an important indicator in carbon sequestration capacity and forest carbon budget evaluation, but there is less focus on shrub biomass. Multi-angle images provide the volume scattering information which could improve inversion accuracy. HJ-1 satellites are the sun synchronous recurrent frozen orbit small satellite constellation for environment and disaster monitoring and forecasting...
The main missions of HJ-1 satellite are to monitor pollution, ecosystem destruction and natural disasters. In recent years, Inhalable particle (PM10) has become the primary pollutant of major cities in China, which seriously affects the living environment of its residents. In this paper, we made use of high-resolution CCD data of HJ-1 satellite to monitor atmospheric inhalable particle (PM10) in Shenzhen...
Vegetation fractional cover which defines the amount of vegetation on the surface of the land, is a key parameter in land surface models. Based on a geometric-optical model in combination with linear spectral mixture analysis, this paper discusses the estimation of shrub fractional cover in Wushen Banner of Inner Mongolia in the Mu Us Sandland using HJ-1B image. Firstly, we acquire the surface reflectance...
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