ATV Test Facilities
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Glossary
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Acronym |
Definition |
Description |
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ADR |
Achievable Data Rate |
Maximal data rate allowed by TDRS for telemetry as a function of received power at TDRS satellite level. |
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AGC |
Automatic Gain Control |
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ATV |
Automated Transfer Vehicle |
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ATV CC |
ATV Control Center |
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BER |
Bit Error Rate |
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Byte |
Set of eight bits |
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CADU |
Channel Access Data Unit |
Telemetry channel unit that is made with a coded transfer frame and attached synchronisation marker |
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CAM |
Collision Avoidance Manoeuvre |
Pre-defined manoeuvre applied in case of emergency. |
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CC |
Control Center |
Ground station that controls space vehicle or a space segment (TDRS constellation for example). |
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CCSDS |
Consultative Commitee for Space data system |
Recommendation for space data system standards |
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CLCW |
Control link control word |
Word inserted in telemetry frame allowing ground control center to verify good reception of telecommand. |
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CLTU |
Command link transmission unit |
Telecommand basic protocol data unit made of one or more telecommand blocks. |
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CMU |
Command & monitoring unit |
Equipment that provides the « DMS » with capabilities to command and monitor avionics ATV items. |
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COP-1 |
command operation protocol |
CCSDS protocol that defines the way to manage telecommands. |
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CPDU |
command pulse distribution unit |
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CPF |
communication processor formatter |
Equipment that generates CCSDS transfert frames |
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DMS |
Data management system |
In that document, this refers to the general vehicle management. |
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Eb/N0 |
Ratio between bit energy and spectral noise |
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EGSE |
electrical ground support equipment |
Allows ATV command and monitoring when vehicle is on ground (quali-fication, launch pad, tests...) |
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FARM |
Frame acceptance reporting mechanism |
Verification made onboard spacecraft in order to verify coherency of telecommand sequence |
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FDIR |
Failure detection isolation and recovery |
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FOP |
Frame operation procedure |
Procedure implemented on ground to manage telecommand |
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FTC |
Fault tolerant computer |
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GNC |
Guidance navigation control |
ATV application software that realizes vehicle navigation and guidance. |
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GPS |
Global positioning system |
Satellites constellation that allows the position and velocity determination by means of a receiver |
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GRTS. |
Gamma Ray Observatory Terminal System |
TDRS ground station associated the additional TDRS satellite placed with in 275°W. |
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GTD |
Geometric Theory of diffraction |
Software computation that allows to simulate radio pattern for high frequencies or structures of large size with comparison with wavelength |
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HLTC |
High level telecommand |
Telecommand that is directly executed by « CPF » without any action of « DMS » |
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HLTM |
High level telemetry |
Telemetry information that are acquired directly by « CPF » without any action of « DMS » |
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I/F |
InterFace |
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ICD |
Interface control document |
Document that defines I/F between two main systems (for example: TDRSS/ATV, ISS/ATV ...) |
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IRD |
Interface requirement document |
Document that defines I/F requirement between two main systems (for example ISS/ATV ...) |
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ISS-SM |
Service module of the international space station |
Module where ATV will be docked |
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kbps |
kilo bits per second |
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LNA |
low noise amplifier |
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MA |
multiple access |
TDRSS service that allows several users to transmit telemetry at the same time. |
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MAP id |
Multiplexed access point identifier |
Aera of telecommand segment header that permits to distinguish different types of telecommand. |
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N0 |
Spectral noise |
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PCDU |
Power and control distribution unit |
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PDE |
Power drive electronics |
TV unit that operates thrusters on GNC orders |
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PFL |
Probability of frame loss |
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prox link |
proximity link |
Bidirectionnal RF link between ATV and ISS-SM. |
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PTD |
packet telecommand decoder |
Asic (single chip) of CPF that decodes direct telecommand (MA28140) |
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QPSK |
Quadriphase shift modulation |
Type of carrier phase modulation that uses four carrier phase values (45°, 135°, 225°, 315° for example) as transmit symbols. |
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RDV |
Rendez vous |
ATV / SM-ISS operations dedicated to ATV / SM-ISS docking. |
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RF |
Radio frequency |
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RFI |
Radio frequency interferences |
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SA |
single access (TDRSS context) selective availibility (GPS context) |
Service that allows one user at a time. Service dedicated to authorized users. |
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Slot |
Elementary message of « SPT » protocol implemented on 1553 bus having 32 bytes length. |
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SN |
Space network |
Part of TDRSS that allows bidirectional link between a user space vehicle and TDRSS ground stations. |
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SPT |
synchronous packet transfer |
Protocol implemented on 1553 bus |
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SSPA |
Solid state power amplifier |
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TC |
telecommand |
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TDRSS |
Tracking and data relay satellite system |
Set of three geostationary satellites situated in 41°W, 174°W and 275°W relay between space vehicule and ground control center. |
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TDRSS CC |
TDRS control center |
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TM |
telemetry |
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TRPS |
transponder |
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VC |
virtual channel |
Characterisation of a transfer frame type (real time TM, delayed TM, idle TM, downloading TM...). |
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VCA |
Virtual channel assembly |
Asic of CPF that is associated to one TM virtual channel. |
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VCM |
Virtual channel multiplexing |
Asic of CPF that generates the packet telemetry transfer frames. It inputs a partial transfer frame from the selected VCA, attaches a synchro-nisation marker, generates parts of the transfer frame header and optionally generates a transfer frame trailer (CLCW particularly). |
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WSC |
White Sands Complex |
TDRS ground stations associated with the nominal TDRS satellites placed in 41°W. and 171°W. |
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ZOE |
Zone of exclusion |
Zone above pacific ocean where TDRSS is disabled in case of no additionnal TDRS satellite (275°W) is used. |
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