A real time low complexity codec for use in low Earth orbit small satellite missions

2005 ◽  
Author(s):  
Y. Bentoutou
Keyword(s):  
Real Time ◽  
Low Complexity ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Small Satellite ◽  
Satellite Missions

scholarly journals Orbit Propagation and Determination of Low Earth Orbit Satellites

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Ho-Nien Shou
Keyword(s):  
Kalman Filter ◽  
Real Time ◽  
Unscented Kalman Filter ◽  
Estimation Method ◽  
Nonlinear Problems ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Positioning Accuracy ◽  
Orbit Propagation

This paper represents orbit propagation and determination of low Earth orbit (LEO) satellites. Satellite global positioning system (GPS) configured receiver provides position and velocity measures by navigating filter to get the coordinates of the orbit propagation (OP). The main contradictions in real-time orbit which is determined by the problem are orbit positioning accuracy and the amount of calculating two indicators. This paper is dedicated to solving the problem of tradeoffs. To plan to use a nonlinear filtering method for immediate orbit tasks requires more precise satellite orbit state parameters in a short time. Although the traditional extended Kalman filter (EKF) method is widely used, its linear approximation of the drawbacks in dealing with nonlinear problems was especially evident, without compromising Kalman filter (unscented Kalman Filter, UKF). As a new nonlinear estimation method, it is measured at the estimated measurements on more and more applications. This paper will be the first study on UKF microsatellites in LEO orbit in real time, trying to explore the real-time precision orbit determination techniques. Through the preliminary simulation results, they show that, based on orbit mission requirements and conditions using UKF, they can satisfy the positioning accuracy and compute two indicators.

scholarly journals In Situ Measurement of Carbon Fibre/Polyether Ether Ketone Thermal Expansion in Low Earth Orbit

Aerospace ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 35 ◽  
Author(s):  
Farhan Abdullah ◽  
Kei-ichi Okuyama ◽  
Isai Fajardo ◽  
Naoya Urakami
Keyword(s):  
Thermal Expansion ◽  
Carbon Fibre ◽  
Material Science ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Small Satellite ◽  
Polyether Ether Ketone ◽  
Ether Ketone ◽  
Orbit Data

The low Earth orbit (LEO) environment exposes spacecraft to factors that can degrade the dimensional stability of the structure. Carbon Fibre/Polyether Ether Ketone (CF/PEEK) can limit such degradations. However, there are limited in-orbit data on the performance of CF/PEEK. Usage of small satellite as material science research platform can address such limitations. This paper discusses the design of a material science experiment termed material mission (MM) onboard Ten-Koh satellite, which allows in situ measurements of coefficient of thermal expansion (CTE) for CF/PEEK samples in LEO. Results from ground tests before launch demonstrated the feasibility of the MM design. Analysis of in-orbit data indicated that the CTE values exhibit a non-linear temperature dependence, and there was no shift in CTE values after four months. The acquired in-orbit data was consistent with previous ground tests and in-orbit data. The MM experiment provides data to verify the ground test of CF/PEEK performance in LEO. MM also proved the potential of small satellite as a platform for conducting meaningful material science experiments.

Real-time orbit determination of Low Earth orbit satellite based on RINEX/DORIS 3.0 phase data and spaceborne GPS data

2020 ◽  
Vol 66 (7) ◽  
pp. 1700-1712
Author(s):  
Chongchong Zhou ◽  
Shiming Zhong ◽  
Bibo Peng ◽  
Jikun Ou ◽  
Jie Zhang ◽  
...  
Keyword(s):  
Real Time ◽  
Orbit Determination ◽  
Low Earth Orbit ◽  
Gps Data ◽  
Earth Orbit ◽  
Orbit Satellite ◽  
Low Earth Orbit Satellite ◽  
Phase Data

scholarly journals Improving Low Earth Orbit (LEO) Prediction with Accelerometer Data

2020 ◽  
Vol 12 (10) ◽  
pp. 1599 ◽  
Author(s):  
Haibo Ge ◽  
Bofeng Li ◽  
Maorong Ge ◽  
Liangwei Nie ◽  
Harald Schuh
Keyword(s):  
Real Time ◽  
Traditional Method ◽  
Initial Conditions ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Accelerometer Data ◽  
Orbit Prediction ◽  
Real Time Applications ◽  
Empirical Coefficients ◽  
Calibration Parameters

Low Earth Orbit (LEO) satellites have been widely used in scientific fields or commercial applications in recent decades. The demands of the real time scientific research or real time applications require real time precise LEO orbits. Usually, the predicted orbit is one of the solutions for real time users, so it is of great importance to investigate LEO orbit prediction for users who need real time LEO orbits. The centimeter level precision orbit is needed for high precision applications. Aiming at obtaining the predicted LEO orbit with centimeter precision, this article demonstrates the traditional method to conduct orbit prediction and put forward an idea of LEO orbit prediction by using onboard accelerometer data for real time applications. The procedure of LEO orbit prediction is proposed after comparing three different estimation strategies of retrieving initial conditions and dynamic parameters. Three strategies are estimating empirical coefficients every one cycle per revolution, which is the traditional method, estimating calibration parameters of one bias of accelerometer hourly for each direction by using accelerometer data, and estimating calibration parameters of one bias and one scale factor of the accelerometer for each direction with one arc by using accelerometer data. The results show that the predicted LEO orbit precision by using the traditional method can reach 10 cm when the predicted time is shorter than 20 min, while the predicted LEO orbit with better than 5 cm for each orbit direction can be achieved with accelerometer data even to predict one hour.

scholarly journals Development of Design Requirements for a Cognitive Assistant in Space Missions Beyond Low Earth Orbit

2017 ◽  
Vol 12 (2) ◽  
pp. 131-152 ◽  
Author(s):  
Güliz Tokadlı ◽  
Michael C. Dorneich
Keyword(s):  
Decision Making ◽  
Real Time ◽  
Domain Knowledge ◽  
Space Vehicle ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Space Operations ◽  
Negative Effect ◽  
Design Requirements ◽  
Mission Control

This study describes the development of requirements for a cognitive assistant (CA) for use onboard a space vehicle/station. For missions beyond low Earth orbit (LEO), delayed communication will limit mission control’s ability to support the space crew in real time. During off-nominal situations, where no procedures have been developed prior to missions, crews must develop responses in real time and may increasingly rely on automation. A systematic approach was used to model the domain knowledge of the collaborative decision-making process of current space operations, extrapolate to missions beyond LEO, and develop the design requirements for a CA. Document analysis and interviews were conducted to create an abstraction hierarchy and a decision-action diagram of the cognitive functions currently performed by space crew, mission control, and onboard automation. These domain models were extrapolated to missions beyond LEO by identifying the breakpoints where current decision-making processes would break down due to increased communication delay between mission control and the space crew. Design requirements were identified for future CA systems that offer real-time decision-making support to mitigate the negative effect of limited support in off-nominal situations. The approach developed for this research can be generalized to identify the design requirements for future support systems in domains beyond space operations.

scholarly journals Real Time On-board Orbit Determination Performance Analysis of Low Earth Orbit Satellites

2015 ◽  
Vol 43 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Eun-Hyouek Kim ◽  
Dong-Wook Koh ◽  
Young-Suk Chung ◽  
Sung-Baek Park ◽  
Hyeun-Pil Jin ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Real Time ◽  
Orbit Determination ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Low Earth Orbit Satellites
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