The objectives of on-orbit servicing (OOS) missions include manipulation, proximity operations and inspection of target satellites. Therefore the servicer satellite often has to be teleoperated at low latency for several minutes to fulfill these tasks. That means communication plays a crucial role for OOS missions because real time teleoperation including high data rates has to be realized. So ...

In this paper, we analyze the performance of TCP in a network that consists of both satellite and terrestrial components. One method, proposed by outside research, to improve the performance of data transfers over satellites is to use a performance enhancing proxy often dubbed “spoofing”. Spoofing involves the transparent splitting of a TCP connection between the source and destination by some ...

After frame synchronization, individual measurands are identified according to the frame location. The decommutator identifies and extracts embedded asynchronous data stream (EADS) words. Thus PCM Decommutator is a very crucial subsystem in the satellite data acquisition unit of satellite ground station. A PCM decommutator is designed and implemented on a Stratix FPGA. The Hardware design compr...

The remote synchronization system RESSOX is a novel concept for a GNSS time keeping system that does not require an on-board atomic clock. RESSOX has been presented as an alternative to the classic GPS scheme and was specifically designed for the Japanese augmentation system QZSS (Quasi-Zenith Satellite System). According to the RESSOX structure, QZSS satellites will carry light and inexpensive...

This work proposes a modified circular fractal antenna array for multiband applications, including WLAN (5.15–5.85 GHz), C-band applications (3.8–4.4 and X-band satellite communication (7.1–7.76 GHz). High Frequency Structure Simulator (HFSS) is used to simulate the antenna. The substrate material FR4 epoxy, which has 4.4 relative permittivity 1.6 mm of thickness. It discovered that only covers...

The short spreading code used by the BeiDou Navigation Satellite System (BDS) B1-I or GPS Coarse/Acquistiion (C/A) can cause aggregately undesirable cross-correlation between signals within each single constellation. This GPS-to-GPS or BDS-to-BDS correlation is referred to as self-interference. A GPS C/A code self-interference model is extended to propose a self-interference model for BDS B1, t...

in the present study, a model of a large lithium polymer (li-po) battery for use in the simulation of hybrid electric vehicles (hevs) is developed. to attain this goal, an equivalent circuit (ec) consisting of a series resistor and two rc parallel networks is considered. the accuracy and the response time of the model for use in an hev simulator are studied. the battery parameters identificatio...

the application of a flight simulator with six degree of freedom (6dof)) in design and analysis of rocket systems is essential. the calibration of a 6dof flight simulator is a challenging problem. this paper focuses on the calibration of a flight simulator and intends to answer the following questions: 1) does experimental design have significant impact on calibration quality? if so, which expe...

a time-domain approach is presented to calculate electromagnetic fields inside a large electromagnetic pulse (emp) simulator. this type of emp simulator is used for studying the effect of electromagnetic pulses on electrical apparatus in various structures such as vehicles, a reoplanes, etc. the simulator consists of three planar transmission lines. to solve the problem, we first model the meta...