Modeling and Simulation Study of Space Data Link Protocol

Ismail Hababeh,Ja’Far Alqatawna,Rizik M H Al-Sayyed,Marwan Nabelsi,Yousef Majdalawi

doi:10.4236/ijcns.2014.710045

Abstract

This research paper describes the design and implementation of the Consultative Committee for Space Data Systems (CCSDS) standards REF _Ref401069962 \r \h \* MERGEFORMAT [1] for Space Data Link Layer Protocol (SDLP). The primer focus is the telecommand (TC) part of the standard. The implementation of the standard was in the form of DLL functions using C++ programming language. The second objective of this paper was to use the DLL functions with OMNeT++ simulating environment to create a simulator in order to analyze the mean end-to-end Packet Delay, maximum achievable application layer throughput for a given fixed link capacity and normalized protocol overhead, defined as the total number of bytes transmitted on the link in a given period of time (e.g. per second) divided by the number of bytes of application data received at the application layer model data sink. In addition, the DLL was also integrated with Ground Support Equipment Operating System (GSEOS), a software system for space instruments and small spacecrafts especially suited for low budget missions. The SDLP is designed for rapid test system design and high flexibility for changing telemetry and command requirements. GSEOS can be seamlessly moved from EM/FM development (bench testing) to flight operations. It features the Python programming language as a configuration/scripting tool and can easily be extended to accommodate custom hardware interfaces. This paper also shows the results of the simulations and its analysis.

Highlights

Telemetry (TM) [2] [3] transmitted from the spacecraft was formatted with a time division and multiplexing schema, where the data was multiplexed in a stream of fixed length data frames
The proposed simulation method aimed at implementing the Consultative Committee for Space Data Systems (CCSDS) standard Space Data Link Layer Protocol into a dynamically loadable shared object (DLL)
Ii) Maximum achievable application layer throughput for a given fixed link capacity. iii) Normalized protocol overhead defined as the total number of bytes transmitted on the link in a given period of time divided by the number of bytes of application data received at the application layer model data sink. iv) The DLL part of the project must be compatible and usable with the Ground Support Equipment Operating System (GSEOS) test environment

Summary

Introduction

Telemetry (TM) [2] [3] transmitted from the spacecraft was formatted with a time division and multiplexing schema, where the data was multiplexed in a stream of fixed length data frames. Each spacecraft had its own data system, which was used only on a specific project. The proposed simulation method aimed at implementing the CCSDS standard Space Data Link Layer Protocol into a dynamically loadable shared object (DLL). CCSDS began publishing standards starting with the Packet Telemetry protocol which could efficiently send packets from the spacecraft [3]. The standards set by CCSDS can be associated usually with five Open Systems Interconnection (OSI) reference model layers; as with most networks, the session and presentation layers are not associated. CCSDS does not define an Application Programming Interface (API) but rather define primitives which are an abstract form of API and can be used as the baseline for an API

Objectives

Results

Conclusion