SIST EN 301 926 V1.2.1:2003

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.HRVWDFLRQDUQLKSatellite Earth Stations and Systems (SES); Radio Frequency and Modulation Standard for Telemetry, Command and Ranging (TCR) of Geostationary Communications Satellites33.070.40SatelitSatelliteICS:Ta slovenski standard je istoveten z:EN 301 926 Version 1.2.1SIST EN 301 926 V1.2.1:2003en01-april-2003SIST EN 301 926 V1.2.1:2003SLOVENSKI
STANDARD



SIST EN 301 926 V1.2.1:2003



ETSI EN 301 926 V1.2.1 (2002-06)European Standard (Telecommunications series) Satellite Earth Stations and Systems (SES);Radio Frequency and Modulation Standard for Telemetry, Command and Ranging (TCR) of Geostationary Communications Satellites
SIST EN 301 926 V1.2.1:2003



ETSI ETSI EN 301 926 V1.2.1 (2002-06) 2
Reference DEN/SES-000-ECSS-1 Keywords control, modulation, satellite, telemetry ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE
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ETSI ETSI EN 301 926 V1.2.1 (2002-06) 3
Contents Intellectual Property Rights.5 Foreword.5 1 Scope.6 2 References.6 3 Definitions and abbreviations.7 3.1 Definitions.7 3.2 Abbreviations.8 4 Applicability.9 5 Modulation requirements.10 5.1 General.10 5.2 Standard modulation.11 5.2.1 Modulating waveforms.11 5.2.2 PCM waveforms and symbol rates.12 5.2.3 Use of subcarriers.13 5.2.4 Choice of subcarrier frequencies.13 5.2.5 Uplink carrier deviation (Frequency Modulation).14 5.2.6 Downlink PM modulation index.14 5.2.7 PM sense of modulation.14 5.3 Spread spectrum modulation.14 5.3.1 General.14 5.3.2 Chip shaping.15 5.4 Coherency properties.16 5.4.1 FEC channel coding.16 6 Requirements on transmitted signals.16 6.1 Frequency stability requirements.16 6.1.1 Uplink.16 6.1.2 Downlink.16 6.2 Turnaround frequency ratio.16 6.3 Polarization.17 6.4 Phase noise.17 7 Link acquisition requirements.17 Annex A (informative): Operational configuration.18 A.1 Configuration 1: on board dual mode receiver and on board dual mode transmitter.19 A.2 Configuration 2: on board dual mode receiver and standard transmitter.20 A.3 Configuration 3: on board dual mode receiver, standard transmitter and dedicated RG SS transmitter.21 Annex B (informative): Hybrid Ranging process description.23 B.1 Presentation.23 B.2 Distance ambiguity resolution.24 B.3 Calibration.25 Annex C (informative): Modulator imperfections.26 C.1 Phase imbalance.26 C.2 BPSK phase imbalance.26 C.3 QPSK phase imbalance.26 SIST EN 301 926 V1.2.1:2003



ETSI ETSI EN 301 926 V1.2.1 (2002-06) 4
C.4 Amplitude imbalance.27 C.5 Data asymmetry.27 C.6 Data bit jitter.27 C.7 PN code asymmetry.27 C.8 PN code chip jitter.27 C.9 Chip transition time.28 C.10 I/Q data bit skew.28 C.11 I/Q PN code chip skew.28 Annex D (informative): SRRC chip filtering.29 Annex E (normative): PN code allocation, assignment and generation.31 E.1 PN code allocation.31 E.2 PN code assignment.31 E.3 PN code generation.31 E.3.1 Telecommand uplink or in-phase channel (Mode MTC2).31 E.3.2 Ranging uplink or quadrature channel (Mode MTC2).32 E.4 Telemetry Downlink.32 E.4.1 Coherent ranging mode (Mode MTM2).32 E.4.2 Non coherent mode (Mode MTM3).33 E.5 PN code libraries.34 Annex F (informative): Performance computations.38 Annex G (informative): FEC coding example.39 Annex H (informative): Bandwidth considerations and assumptions.40 Annex I (informative): Void.41 Annex J (informative): Modulation implementation.42 Annex K (informative): Bibliography.43 History.44
SIST EN 301 926 V1.2.1:2003



ETSI ETSI EN 301 926 V1.2.1 (2002-06) 5
Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http://webapp.etsi.org/IPR/home.asp). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword This European Standard (Telecommunications series) has been produced by ETSI Technical Committee Satellite Earth Stations and Systems (SES). The contents of the present document are subject to continuing work within TC-SES and may change following formal TC-SES approval. Should TC-SES modify the contents of the present document it will then be republished by ETSI with an identifying change of release date and an increase in version number as follows: Version 1.m.n Where: - the third digit (n) is incremented when editorial only changes have been incorporated in the specification; - the second digit (m) is incremented for all other types of changes, i.e. technical enhancements, corrections, updates, etc.
National transposition dates Date of adoption of this EN: 14 June 2002 Date of latest announcement of this EN (doa): 30 September 2002 Date of latest publication of new National Standard or endorsement of this EN (dop/e):
31 March 2003 Date of withdrawal of any conflicting National Standard (dow): 31 March 2003
SIST EN 301 926 V1.2.1:2003



ETSI ETSI EN 301 926 V1.2.1 (2002-06) 6
1 Scope The present document applies to Telemetry, Command and Ranging (TCR) systems operating typically in the following bands: • 5 850 MHz; 6 725 MHz uplink; 3 400 MHz; 4 200 MHz downlink; • 12 750 MHz; 14 800 MHz and 17 300 MHz; 18 100 MHz uplink; 10 700 MHz; 12 750 MHz downlink; for Geostationary Communications Satellites. The present document sets out the minimum performance requirements and technical characteristics of the ground/satellite Radio Frequency (RF) interface partially based on Spread Spectrum Multiple Access (SSMA). With the growing number of satellites, the co-location constraints and the maximization of bandwidth for Communications Missions, and interference has motivated the elaboration of the present document for geostationary satellites based on Spread Spectrum techniques. The present document addresses the following applications: • Telemetry; • Command (Telecommand); • Ranging. Currently, no RF and Modulation standard exists for the TCR of geostationary communication satellites. The aim of the present document is to respond to such requirements. There are consequently similarities with existing agency standards, such as those listed in annex I, although some specifics have been introduced to respond to the requirement of multiple access for collocated geostationary communication satellites. 2 References The following documents contain provisions which, through reference in this text, constitute provisions of the present document. • References are either specific (identified by date of publication and/or edition number or version number) or non-specific. • For a specific reference, subsequent revisions do not apply. • For a non-specific reference, the latest version applies. [1] ETSI TR 101 956: "Satellite Earth Stations and Systems (SES); Technical analysis of Spread Spectrum Solutions for Telemetry Command and Ranging (TCR) of Geostationary Communications Satellites". SIST EN 301 926 V1.2.1:2003



ETSI ETSI EN 301 926 V1.2.1 (2002-06) 7
3 Definitions and abbreviations 3.1 Definitions For the purposes of the present document, the following terms and definitions apply: binary channel: binary communications channel (BPSK has 1 channel, QPSK has 2 channels) Spread Spectrum Multiple Access (SSMA)(== Code Division Multiple Access (CDMA)): modulation of a carrier by a code sequence, with association of a code to each user data rate: total number of uncoded data bits per second after packet and frame encoding NOTE: See figures 1 and 2. This is the Data Rate used in Link Budgets in [1]. symbol rate: rate of binary elements, considered on a single wire, after FEC coding NOTE: See figures 1 and 2. channel symbol rate: rate of binary elements, considered on a single wire, after FEC coding and channel allocation NOTE: See figure 2. This applies only to multi-channel modulations, thus to spread spectrum QPSK modes and not to standard PM/FM modes. Co-located Equivalent Capacity (CEC): number of collocated satellites that can be controlled with a perfect power balanced link between the ground and the satellite PACKET ENCODING (BLOCK CODE, INTERLEAVE ETC)FECCODING(EG CONV)WAVEFORMFORMATTING(EG NRZ-L)FM or PMMODULATIONRNGTMRF CARRIERRANGING TONESBPSKMODULATIONSUBCARRIERDATA SOURCEDATA RATESYMBOL RATESCOPE OF THE PRESENT DOCUMENTOPTIONAL Figure 1: Functional stages of transmit chain for standard modulation SIST EN 301 926 V1.2.1:2003



ETSI ETSI EN 301 926 V1.2.1 (2002-06) 8
PACKET ENCODING (BLOCK CODE, INTERLEAVE ETC)FECCODING(EG CONV)WAVEFORMFORMATTING(EG NRZ-L)OQPSKRF CARRIERALLOCATIONOF SYMBOLSTO CHANNELSDATA SOURCEDATA RATESYMBOL RATESCOPE OF THE PRESENT DOCUMENTI CH. BPSKMODULATIONQ CH. BPSKMODULATION+I CHANNEL PN CODEQ CHANNEL PN CODECHANNEL SYMBOL RATEOPTIONAL Figure 2: Functional stages of transmission chain for spread spectrum modulation 3.2 Abbreviations For the purposes of the present document, the following abbreviations apply: BPSK Binary Phase Shift Keying CDMA Code Division Multiple Access CEC Co-located Equivalent Capacity COM COMmunication channel CW Continuous Wave DSSS Direct Sequence Spread Spectrum DRSS Data Relay Satellite System (ESA) DRTS Data Relay and Tracking System (NASDA) ECSS European Co-operation for Space Standardization ESA European Space Agency FEC Forward Error Correction FM Frequency Modulation GTO Geostationary Transfer Orbit HPA High Power Amplifier LEOP Launch and Early Orbit Phase MTC1 TeleCommand Mode 1 MTC2 TeleCommand Mode 2 MTM1 TeleMetry Mode 1 MTM2 TeleMetry Mode 2 MTM3 TeleMetry Mode 3 NASA National Aeronautics and Space Administration (USA) NASDA National Astronautics and Space Development Administration (Japan) NRZ-L Non Return to Zero-Level NRZ-M Non Return to Zero-Mark OQPSK Offset Quaternary Phase Shift Keying PCM Pulse Coded Modulation PDF Probability Density Function PM Phase Modulation PN Pseudo Noise SIST EN 301 926 V1.2.1:2003



ETSI ETSI EN 301 926 V1.2.1 (2002-06) 9
PSD Power Spectral Density QPSK Quaternary Phase Shift Keying RF Radio Frequency RG RanGing SP-L Split Phase-Level (alias Bi-Φ -Level or Manchester encoded) SRRC Square Root Raised Cosine SS Spread Spectrum SSMA Spread Spectrum Multiple Access STD STanDard (for standard modulation) TC TeleCommand TCR Telemetry, Command and Ranging TDRSS Tracking and Data Relay Satellite System (NASA) TM TeleMetry TTC/TT&C Telemetry Tracking and Command (== Telemetry, Command and Ranging, TCR) UQPSK Unbalanced Quaternary Phase Shift Keying w.r.t with respect to 4 Applicability The present document applies to the typical TCR scenario shown in figure 3. The scenario comprises k satellites, which may be co-located on the same orbital position. Each satellite also goes through other mission phases like LEOP, drift and possibly emergency mode. These satellites may be controlled/monitored by N different TCR Ground Stations. The TCR links defined in the present document have to coexist with the Communication ground terminals and associated links also shown in figure 3. The present document defines the modulation on the TCR links. Modulation formats are described in clause 5 and the associated mission phases are described in annex A. COMMS TRAFIC1NTCRGROUNDTERMINALSSPACE SEGMENT:GTO, DRIFT ORCO-LOCATED SATELLITES1N’TCRGROUNDTERMINALSCOMMS TRAFICTC AND RANGINGTM AND RANGINGGROUND SEGMENTGROUND SEGMENTCOMMSTERMINALSCOMMSTERMINALSSatellite 1Satellite 2Satellite N Figure 3: Typical applicable scenario SIST EN 301 926 V1.2.1:2003



ETSI ETSI EN 301 926 V1.2.1 (2002-06) 10 5 Modulation requirements 5.1 General The generic system functional block diagram is shown in figure 4. Modulation modes and configurations are shown in table 1. TC DATACONDITIONINGSTANDARDMODE TC TxDSSSMODE TxSTD MODETC RxDSSS MODETC RxSTD MODETM TxDSSS MODETM TxRANGINGSUB SYSTEMSTANDARDMODE TC RxDSSSMODE RxTM DATACONDITIONINGTCTMTMTMTCTCGROUND SEGMENTSPACE SEGMENTPN code to RG tone processingRG toneRG PN code Figure 4: Generic system functional block diagram Table 1: Modulation modes and potential configurations
All standard mode All spread mode Hybrid mode Uplink MTC1: PCM/BPSK/FM MTC2: PCM/SRRC-UQPSK MTC2: PCM/SRRC-UQPSK Downlink (with ranging (see note): requires uplink present) MTM1: PCM/BPSK/PM MTM2: PCM/SRRC-OQPSK (PN code clock/epoch sync to uplink clock/epoch) MTM1: PCM/BPSK/PM Downlink (without ranging: can operate without uplink present)) MTM1: PCM/BPSK/PM MTM3: PCM/SRRC-OQPSK (PN code clock/epoch independent of uplink clock/epoch) MTM1: PCM/BPSK/PM NOTE: Further definition of ranging signals is given in following clauses.
In order to retain backward compatibility with existing ground networks and to allow simple operation during LEOP, in addition to the new Spread Spectrum modes, the existing "standard" FM/PM modulation modes are retained. It is envisaged that telecommand and telemetry modulation formats shall be independently configurable, allowing for example the following configuration possibilities (see also annex A for implementations and TR 101 956 [1]): •
all standard mode (as has existed in previous systems) using tone ranging on FM uplink (MTC1) and PM (MTM1) downlink; •
all spread mode (Direct Sequence Spread Spectrum: DSSS) using PN spreading code regenerative ranging on suppressed carrier up-and down-links (MTC2 and MTM2); •
hybrid mode using PN spreading code ranging on suppressed carrier DSSS uplink (MTC2), and tone ranging on PM downlink (MTM1). SIST EN 301 926 V1.2.1:2003



ETSI ETSI EN 301 926 V1.2.1 (2002-06) 11 In addition, on the spread spectrum (DSSS) mode downlink, there are 2 PN code sets defined, for coherent and non-coherent modes (modes MTM2 and MTM3 respectively). The physical partitioning of the functions may not exactly follow that shown in the system functional block diagram. The modulation configuration of the various modes is described in the rest of clause 5. Possible allocation of modes to mission phases is defined in annex A. 5.2 Standard modulation The Standard mode modulation formats shall be Frequency Modulation (FM) on Telecommand uplink and Phase Modulation (PM) on Telemetry downlink. The standard modes shall be known as MTC1 and MTM1 respectively. 5.2.1 Modulating waveforms The following modulating waveforms are permitted in standard modes: • Telemetry (mode MTM1): a sine wave sub carrier, itself BPSK modulated by PCM data; • Telecommand (mode MTC1): a sine wave subcarrier, itself BPSK modulated by PCM data; • Ranging (mode MTC1 + MTM1): an unmodulated sinewave subcarrier or combination of a number of such subcarriers. SIST EN 301 926 V1.2.1:2003



ETSI ETSI EN 301 926 V1.2.1 (2002-06) 12 5.2.2 PCM waveforms and symbol rates The PCM waveform formatting is defined in figure 5:
NRZ-L level A signifies symbol "1"
level B signifies symbol "0" SP-L level A during the first half-symbol followed by
level B during the second half-symbol signifies symbol "1"
level B during the first half-symbol followed by
level A during the second half-symbol signifies symbol "0" NRZ-M level change from A to B or B to A signifies symbol "1"
no change in level signifies symbol "0"
Figure 5: PCM waveforms formatting PCM data signals shall be limited to the waveforms and symbol rates given in table 2. Table 2: PCM waveforms and rates Function Symbol rate (symbols/s) PCM waveform Special requirements Telecommand (Mode MTC1) Between 8 sym/s up to 4 000 sym/s (see note) NRZ-L NRZ-M
Telemetry (Mode MTM1) Between 64 sym/s up to 20 ksym/s (see note) NRZ-L NRZ-M SP-L
NOTE: Coherency between symbols and sub-carrier is required.
SIST EN 301 926 V1.2.1:2003



ETSI ETSI EN 301 926 V1.2.1 (2002-06) 13 5.2.3 Use of subcarriers The subcarriers and modulating waveforms that shall be used are listed in table 3. Table 3: Subcarriers used with FM Or PM Rf carriers Function Subcarrier (kHz) Modulation waveform Subcarrier waveform Telecommand (Mode MTC1)
8 or 16 NRZ-L NRZ-M Sine Telemetry (Mode MTM1) 0,1 to 1 000 NRZ-L NRZ-M SP-L Sine Ranging (Mode MTM1 + MTC1) 0,1 to 100 None (CW Tone) Sine
5.2.4 Choice of subcarrier frequencies For telecommand transmission using a subcarrier, only two subcarrier frequencies are permitted. The subcarrier frequency shall be 8 kHz for all telecommand rates up to 2 000 sym/s. A 16 kHz subcarrier shall be used only in cases where the 4 000 sym/s symbol rate is needed or when required by the operator. The choice of the ranging and telemetry subcarrier frequencies shall take into account the requirements of: • carrier acquisition by the ground receivers; • compatibility between ranging and telemetry; • occupied bandwidth. Modulation of subcarriers used for telemetry and telecommand shall be BPSK (for ranging the subcarriers are unmodulated tones).
The following requirements shall be met for TC and TM subcarriers: • for NRZ-L and NRZ-M signal waveforms, the subcarrier frequency shall be a multiple (integer) of the symbol rate from 4 to 1 024; •
for SP-L signal waveforms, the subcarrier frequency shall be an even integer multiple of the symbol rate from 4 to 1 024; •
at each transition in the PCM formatted waveform, the subcarrier shall be reversed in phase; •
the transitions in the PCM formatted waveform shall coincide with a subcarrier zero crossing to within ±2,5 % of a subcarrier period; •
at all times, for more than 25 % of a subcarrier period after a phase reversal, the phase of the modulated subcarrier shall be within ±5° of that of a perfect BPSK signal; • for NRZ-L and SP-L waveforms, the beginning of the symbol intervals shall coincide with a positive-going subcarrier zero crossing for symbols "1" and with a negative-going zero crossing for symbols "0"; • for NRZ-M waveforms, the beginning of the symbol intervals shall coincide with a subcarrier zero crossing. SIST EN 301 926 V1.2.1:2003



ETSI ETSI EN 301 926 V1.2.1 (2002-06) 14 5.2.5 Uplink carrier deviation (Frequency Modulation) The FM deviation (modulation depth) is stated in table 4. Table 4: FM uplink frequency deviation Function Deviation (kHz) Telecommand (PCM/BPSK/FM) (Mode MTC1) Up to ±400 kHz Ranging Earth-to-space (FM) (Mode MTC1) (total deviation of all simultaneous major and minor tones) Up to ±400 kHz
5.2.6 Downlink PM modulation index Minima and maxima of the modulation index are stated in table 5. Table 5: PM modulation index Function Min.
(radians peak) Max.
(radians peak) Telemetry (PCM/BPSK/PM) (Mode MTM1) 0,1 1,5 Ranging space-to-Earth (PM) (Mode MTM1) 0,01 1,5
5.2.7 PM sense of modulation A positive-going video signal (modulated TM subcarrier and/or ranging) shall result in an advance of the phase of the downlink Radio Frequency carrier. 5.3 Spread spectrum modulation 5.3.1 General The spread modulation formats shall be: •
Telecommand Uplink: Square Root Raised Cosine filtered Unbalanced QPSK (SRRC-UQPSK); •
Telemetry Downlink: SRRC filtered Offset QPSK (SRRC-OQPSK). The spread modulation modes shall be as follows: •
Mode MTC2: spread spectrum telecommand uplink; •
Mode MTM2: spread spectrum telemetry downlink, coherent mode (long PN code); •
Mode MTM3: spread spectrum telemetry downlink, non-coherent mode (short PN code). The Spread Spectrum modulation characteristics shall be as defined in table 6. The modulation modes listed shall be available for communications between the Spacecraft and the Earth Terminal for a range of data rates. Symbol rates referred to in the present document include the channel coding overhead whenever channel coding is applied. The Symbol rate shall be selected depending on requirements, link budget and multiple access capabilities. Modulator imperfections are defined in annex C. SIST EN 301 926 V1.2.1:2003



ETSI ETSI EN 301 926 V1.2.1 (2002-06) 15 Table 6: Spread spectrum link modulation modes
Telecommand link, Mode MTC2 Coherent telemetry link, Mode MTM2 Non-coherent telemetry link, Mode MTM3 Symbol Rate 4 000/2n n=0
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