ISO 20205:2015 download free.Space data and information transfer systems Spacecraft Onboard Interface Systems Low Data-Rate Wireless Communications for Spacecraft Monitoring and Control.
1 INTRODLJCTH)N
1,1 PURPOSE
ISO 20205 presents the recommended practices for the utiliiation of low data-rate wireless communication technologies in support of spacecraft ground testing and flight monitoring and control applications. Relevant technical background information can he found in reference 131.
The recommended practices contained in this document enable member agencies to select the best option(s) available for interoperuble wireless communications in the support of spacccraft monitoring and control applications, The specification of a Recommended Practice facilitates interoperable communications and forms the foundation for c-support of communication systems between separate member space agencies.
12 SCOPE
This Recommended Practice is targeted towards monitoring and control systems. typically low data-race and low-power wireless-based applications.
1.3 APPLICABILITY
This Recommended Practice specities protocols (including at least the Physical II’HYI layer and Medium Access Control (MACI sublayer of the Open Systems Interconnection lOSt I Model—see reference I Fl ) that enable a basic interoperable wireless communication system to support low data-rate spacecraft monitoring and control applications.
1.4 RATIONALE
From an engineering standpoirn. mission managers, along with cngitiecrs and developers. are faced with a plethora of wireless communication choice., both standards-based and proprietary. This Recommended Practice provides guidance in the selection of systems necessary to achieve interoperable communications in support of wireless, low data-rate monitoring and control.
1.5 I)OCtIMENT STRUCTURE
ISO 20205 is composed from a top-down (technology) perspective, first defining the technology as a recommended practice, then providing informative material supporting specific application proiilcs, (For more information on space mission usc cases addressed by wireless technologies. sec reference 131).
Section 2 provides an informational overview of the rationale and benefits of spacecraft onboard wireless technologies for usc in spacecraft monitoring and control operations.
2 OVERVWW
2.1 RATIONALE AND BENEFITS
Monitonng and controlling the behavior of a spacecraft and launch systems, dunng testing phusc’ on ground or during nominal operations in orbit, is the key to ensuring the correct functioning of various onhoard systems and structures, the responses of these systems in iheir operational working environments, and the long-term reliabilily of the spacecraft. These data are also highly significant when compiling lessons learned that will he applied Lu building better space systems and increasing the reliability of future space components. (Refer Lu reference 131 11r a comprehensive overview of application domains and Ii,r a detailed summary of RP communications and restrictions in differing operational environments.)
The quantity of acquired spacecraft functional data depends on the ability to monitor required parameters at precise locations within a given project time and cost envelope. Hundreds and often thousands of data measurement locations arc required, steadily increasing the mass (acquisition systems, cables, and hamesscs) and the project costs and time (installation and verification of each new sensorl.
The use of wireless technologies is foreseen to reduce the integration effort, cost, and time typically required to instrument a high number of physical measurement points on a space structure. Technicians should need lcss time in integrate and verify their installations, while the risk of mechanically damaging interfaces during the process should be reduced. Large structures should see health monitoring equipment mass reduced, while last-minute changes in the instrumentation (e.g., addition/removal of sensing nodes at measurement points should he easier to accept at project level. One of the byproducts of using wireless technologies in space systems is the extra flexibility introduced when implementing wireless fault-tolerance and redundancy schemes.
An overriding consideration in ISO 20205 is the desire to provide recommendations that utili,c wireless technology to augment the overall networking infrastructure in a spacecraft rather than to provide dedicated data transport to particular end-to-end application-specific subsystems. That is, although the recommendations specified in this document are related to relatively small-scale Peronal Area Networks (PANs) rather the more familiar Local Area Networks (L.ANs) such as Ethernet. the desire is for wireless PANs to function as natural extensions of the backbone LAN. This implies in particular that the recommendations specified herein focus on providing wireless data transport across the lower levels of the OSI model (PI-IY and MAC) and not on achieving higher-level application-specific behavior.
2.2 SCOPE OF INTEROPERABIIATY
The intent of the recommended practices promulgated in this book is to provide a framework for establishing a scalable wireless infrastructure for low-rate data transport that will (I) support traffic generated by diverse sensor types. multiple application-specific devices, and devices supplied by multiple different vendou and (2) facilitate operation of multiple wireless networks in the same bandwidth with minimal interference The recommended
3 RECOMMENDED PRACTICES I-OR LOW DATA-RATE
WIREIJSS COMMUNICATIONS FOR SPA(:ECRAFT MONITORING ANI) CONTROL
3.1 OVERVIEW
This section prcscnts the rccommcndcd practices for spacecraft n:onitonnR and control applications acing low data-raw wiirkcs co,nnunica:ion technologks. (Sec table C-2 for a non-chaustive set of example use-cases that may hcnef from tising low data-rate wireless communications.
As discussed in section 2. in order to ensure the most basic inicropcrubility between low data-rate wireless communication devices, the current recommendations are focused on specification of functionality at the air interface PHY layer and the MAC sublayer of the OSI model, Following this guideline, two different compliant systems would thus be able to share the medium and potcntially join the same wireless network.
3.2 RF.COMMENDEI) PRACTICES
3.2.1 APPLICATIONS SUITED FOR SINGI.F.-IIOP CONTENTION-BASED
COMMUNICATK)NS
For spacecraft monitoring and control activities employing low data-rate contention-based wireless communications in single-hop contigurations. both the air interface PHY layer and the MAC sublayer shall comply with the IEEE g02.15.4-2011 specification (reference III).
Single-hop contention-based communication networks and devices should utilize the 2.4 GHz frequency band. See annex D for rationale pertaining to 2.4 OHs band preferences see reference 131 for Electromagnetic Interference EMI) considerations of the 2.4 0Hz frequency band.)
3.2.2 APPLICATIONS StilTED FOR SINGLE.HOP SCHEDUI.EI) MEDIUM- ACCESS COMMUNICATIONS
For spacecraft monitoring and control activities employing low data-rate communications utilizing a scheduled medium-access scheme in a single-hop configuration, both the air interface PHY layer and the MAC sublayer shall comply with the ISA 100.1 la-201 I PHYlayer and MAC’suhlaycr specifications (reference 121).
3.2.3 RESTRICTIONS/H AZARI)S
Vhcn selecting a wireless technology for application in a N-cecraft environment, the risks as.sociaicd with the selected radio frequency band, transmission power level, and physical location should be taken into account kw the following governing environmental factors:
a) Operation in explosive environments;
b) RF exposure levels in excess of governmental limits (sec annex D);
c) Electromagnetic Compatibility (EMC).