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There are two typical types of sampling mode in the geolocation of satellite interference: ultra-wideband sampling and narrowband sampling. Besides the measurement error, in narrowband case, the process of ephemeris correction will introduce considerable approximation error and crystal drift error in down convertor (DC), due to both the time-varying feature of ephemeris and non-synchronous sampling...
There are some shortcomings in the delay tolerant network (DTN) routing algorithm, such as low message delivery rate, low network efficiency and high cost in the satellite network. In order to solve the problem above, this paper proposes a limited copy algorithm MPWLC based on service probability. In MPWLC, not only is the number of copies limited, but the storage resources of the satellite are also...
As in-line interference between geostationary(GEO) and Non-Geostationary(NGEO) systems is becoming more and more serious. We propose an efficient utilisation of the adaptive modulation and coding (AMC) scheme for spectral coexistence of GEO and NGEO satellites to mitigate in-line interference. Results of Simulation show that the proposed scheme can improve the performance of the NGEO system in comparison...
This paper introduces an ant colony routing and wavelength assignment algorithm based on cross-layer design (CL-ACRWA), which can overcome the adverse effects of Doppler wavelength shift on data transmission in optical satellite networks. Firstly, a cross-layer optimization model is built, which considers the Doppler wavelength shift, the transmission delay as well as wavelength-continuity constraint...
In this paper we present a decision feedback channel estimation way for the mobile satellite communication system in order to improve the bit error performance. The transmission is disturbed not only by shadowing and multipath effects and additive white Gaussian noise, but also by the weather attenuation. The conventional Least Square(LS) is not well suited to detect the transmitter sequence, whereas...
An efficient modulation and coding scheme combined with multiple LDPC codes and PPM modulation is proposed to mitigate the effect of atmospheric turbulence, which can have an unfavorable impact on the reliability of the communication link in the laser channel of the integration network of satellite and ground. The research is mainly about the reliability of the communication link under different orders...
A cross-layer based ant colony optimization (ACO) for routing and wavelength assignment (RWA) algorithm (CL-ACORWA) in an optical satellite network is proposed. The main objective is to enhance the network robustness. At first, a cross-layer optimization model is designed, which considers the Doppler wavelength shift of the physical layer and the transmission delay of the network layer. Then an ant...
In order to solve the problem of introducing additional Total Degradation (TD) in adaptive satellite system caused by fixed High Power Amplifier (HPA) operating point, the paper proposes an adaptive HPA Input Back-Off (IBO) algorithm carried out on the gateway side in the Forward Link of the system based on Adaptive Coding and Modulation (ACM) techniques. On the other hand, the traditional way of...
According to the developing trend of increasing the quality of global Search and Rescue (SAR) service, this paper analyses several typical global SAR systems including COSPAS-SARSAT and SAR/GNSS from the perspective of user position determination method and report process. At last, it provides some new thoughts about global SAR system development.
The spatial rainfall is one of the key inputs for the distributed hydrological model, and their precisions heavily affect the accuracy of streamflow predictions from a hydrological model. Satellite-based rainfall products are expected to offer an alternative to ground based rainfall estimates in the present and the foreseeable future. So, the present study mainly deals with the comparison between...
The Merzbacher Glacial Lake located in the Sary Jaz-Kumarik River Basin has severe impacts on the environment and human well-being in downstream of the AKSU River in China. The Merzbacker Lake has flooded with increased frequency in recent years with the climate warming. It is vital to strengthen observation and monitoring of the Merzbacker Lake, especially by remote sensing data. Large portion by...
Under the guidance of the comprehensive RDSS, a new three-satellite high-precision RDSS/RNSS combination positioning method is proposed in this paper, which uses a special designed RDSS/RNSS satellite and the others RNSS satellites to determine user position. The key research focuses on its principle and intending performance and lifesaving application.
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