Galileo OS SIS ICD (797928), страница 5
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The E5signal shares the band with the co-primary Aeronautical RadionavigationService (ARNS) (ITU-R Radio Regulations). Moreover, it shares theband with other RNSS-signals provided by EGNOS, GPS-L5,GLONASS etc. as well as signals of the ARNS (DME, TACAN). Alsofound in the band is the JTIDS-MIDS signal which is permitted on anNIB.E5a-SignalThe Galileo E5a-signal is an inherent element of the E5-signal andconsists of a data-channel transmitted in the in-phase component and apilot-channel transmitted in the quadrature component. The E5a-signalprovides the F/NAV message supporting Galileo Open Service andoverlaps (in the spectrum) with the GPS-L5-signal.E5b-SignalThe Galileo E5b-signal is an inherent element of the E5-signal andconsists of a data-channel transmitted in the in-phase component and apilot-channel transmitted in the quadrature component.
The E5b-signalprovides the I/NAV message and supports Safety of Life service, Galileosystem integrity and Open Service.E6-SignalThe Galileo E6-signal consists of the signal components E6-B and E6-Cand is transmitted in the frequency band 1215 - 1300 MHz allocated on aworldwide co-primary basis (ITU-R Radio Regulations), sharing withradar systems of the radio navigation and radiolocation service. Thesignal components E6-B and E6-C are data-channel and pilot-channelrespectively. The E6-signal provides the C-NAV message and supportsCommercial Service.E1- SignalThe Galileo E1-signal comprises the signal components E1-B and E1-Cand is transmitted in the frequency band 1559 - 1610 MHz allocated toRNSS and ARNS on a worldwide co-primary basis (ITU-R RadioRegulations).The signal components E1-B and E1-C are data-channel and pilotchannel respectively. The E1-signal provides the I/NAV message andsupports Safety of Life service, Galileo system integrity and OpenService.Navigation Data Sequence of bits carrying the navigation data information by using aStreamframe structured transmission protocol.F/NAV Message Freely accessible navigation message provided by the E5a signal forOpen Service.I/NAV Message Integrity navigation message type provided by E5b and E1-B signals,supporting Safety of Life Service and providing extended systemintegrity information.C/NAV Message Commercial navigation message type provided by the E6-B signal©, 2006, European Space Agency / Galileo Joint UndertakingDocument subject to terms of use and disclaimers p.
2-4.Pilot channelReceiverreferencebandwidthBOC(fsub,fchip)BBBBBOCc(fsub,fchip)B18BBBBBPageBinary Offset Carrier modulation, with subcarrier frequency fsub and chiprate fchip, where frequencies are indicated as multiples of 1.023 MHz. Forexample, a BOC(10,5) signal has a subcarrier frequency of 10x1.023MHz=10.230 MHz and a code chip rate of 5x1.023MHz=5.115 MHz.Unless specified otherwise, the subcarrier-function of code-chips issign[sin(2*pi*fsub*t)], with sub-carrier frequency fsub and code-chipsstarting at t=0Binary Offset Carrier modulation-cosine. It is defined as above, but withthe subcarrier-function of code-chips according to sign[cos(2*pi*fsub*t)],with sub-carrier frequency fsub and code-chips starting at t=0.BBGAL OS SIS ICD/D.0Draft023/05/2006supporting Commercial Service.A data channel is the result of modulating ranging code, sub-carrier (ifpresent) and secondary code with a navigation data stream.A pilot channel (or dataless channel) is made of ranging code, sub-carrier(if present) and secondary code only, not modulated by a navigation datastream.The bandwidth of a hypothetical receiver with ideal (rectangularfrequency response) input filters.Data channelBReference:Issue:Revision:Date:BBBBBB©, 2006, European Space Agency / Galileo Joint UndertakingDocument subject to terms of use and disclaimers p.
2-4.BReference:Issue:Revision:Date:GAL OS SIS ICD/D.0Draft023/05/2006Page195. GALILEO FREQUENCY PLAN5.1 FREQUENCY BANDSThe Galileo Navigation Signals are transmitted in the four frequency bands indicated in bluein Figure 2. These four frequency bands are: the E5a band, the E5b band, the E6 band and theL1 band. They provide a wide bandwidth for the transmission of the Galileo Signals.365HARNS BandsARNS BandsRNSS BandszMH1591Hz1575.42MzMH1559MHz1544154 MHz5MHzGPS BandsGalileo SAR DownlinkGalileo Bands (Navigation)L1SAR1300MHz1278.750MHz126HzzMH7M1231227zHz5ME61207.140MHMHL2121zE5b1.7951191164MHz1176.45MHzE5a/L5RNSS BandsFigure 2: Galileo Frequency PlanThe frequency bands have been selected in the allocated spectrum for Radio NavigationSatellite Services (RNSS) and in addition to that, E5a, E5b and L1 bands are included in theallocated spectrum for Aeronautical Radio Navigation Services (ARNS), employed by CivilAviation users, and allowing dedicated safety-critical applications.5.2 CARRIER FREQUENCIES AND BANDWIDTHSGalileo carrier frequencies are shown in Table 1.
The beginning and ending frequencies ofeach band are reported in Figure 2.36H367HSignalE5aE5bE5 (E5a+E5b)E6E1Carrier Frequency1176.450 MHz1207.140 MHz1191.795 MHz1278.750 MHz1575.420 MHzTable 1: Carrier Frequency per SignalThe Rx reference bandwidths and polarisations are specified in Table 2.368H©, 2006, European Space Agency / Galileo Joint UndertakingDocument subject to terms of use and disclaimers p. 2-4.SignalReference:Issue:Revision:Date:GAL OS SIS ICD/D.0Draft023/05/2006Page20Rx Reference BandwidthPolarisationE551.150 MHzRHCPE640.920 MHzRHCPE124.552 MHzRHCPTable 2: Galileo signals Rx reference bandwidths5.3 MULTIPLE ACCESSAll Galileo transmitting satellites share the same frequency bands, making use of CodeDivision Multiple Access (CDMA) technique. Spread Spectrum signals are transmittedincluding different ranging codes per signal component, per signal, per frequency and perGalileo satellites.©, 2006, European Space Agency / Galileo Joint UndertakingDocument subject to terms of use and disclaimers p.
2-4.Reference:Issue:Revision:Date:GAL OS SIS ICD/D.0Draft023/05/2006Page216. GALILEO SIGNALS AND MAPPING TO SERVICESFigure 3 illustrates the baseline Galileo signals’ spectral characteristics as well as modulation,chip rate, and data rate.369HE5a Signal:Data +PilotBPSK mod.Rc =10.23 McpsRs =50 spsOS/CSServicesE5b Signal:Data +PilotBPSK mod.Rc =10.23 McpsRs =250 spsOS/CS/SoLServices50 x1.023 MHzSpectral componentnon discussed in thisSIS ICDE6 Signal:Data + PilotBPSK mod.Rc=5.115 McpsRs=1000 spsCS ServiceSpectral componentnon discussed in thisSIS ICD40x1.023 MHzE1 Signal:Data + PilotBOC(1,1) mod.Rc =1.023 McpsRs =250 spsOS/CS/SoLServices24 x1.023 MHzFrequency(MHz)1191.795 MHz1278.75 MHz1575.42 MHzE5 Signal:AltBOC (15,10) mod.Figure 3: Galileo frequency spectrumEach Galileo satellite transmits navigation signals denoted as E1, E6, E5a and E5b signals.••••E1 signal: E1 is an open access signal transmitted in the L1 band comprising a datachannel E1-B and a pilot (or dataless) channel E1-C.
It has unencrypted ranging codesand navigation data, accessible to all users. The E1-B data stream also containsunencrypted integrity messages and encrypted commercial data. The E1-B data rate is125 bps. The E1 signal supports the OS, CS, and the SoL serviceE6 signal: E6 is a commercial access signal transmitted in the E6 band that includes adata channel E6-B and a pilot (or dataless) channel E6-C. Its ranging codes and dataare encrypted. A data rate of 500 bps allows the transmission of added-valuecommercial data.
The E6 signal is a dedicated signal for supporting the CSE5a signal: E5a is an open access signal transmitted in the E5 band that includes adata channel and a pilot (or dataless) channel. The E5a signal has unencrypted rangingcodes and navigation data, which are accessible by all users. It transmits the basic datato support navigation and timing functions, using a relatively low 25 bps data rate thatenables more robust data demodulation. The E5a signal supports the OSE5b signal: E5b is an open access signal transmitted in the E5 band that includes adata channel and a pilot (or dataless) channel. It has unencrypted ranging codes andnavigation data accessible to all users.
The E5b data stream also contains unencryptedintegrity messages and encrypted commercial data. The data rate is 125 bps. The E5bsignal supports the OS, CS and SoL serviceUUUUUUUU©, 2006, European Space Agency / Galileo Joint UndertakingDocument subject to terms of use and disclaimers p. 2-4.Reference:Issue:Revision:Date:GAL OS SIS ICD/D.0Draft023/05/2006Page22The E5a and E5b signals are modulated onto a single E5 carrier using a technique known asAltBOC.
The composite of the E5a and E5b signals is denoted as the E5 signal and can beprocessed as a single large bandwidth signal with an appropriate user receiverimplementation. Power sharing between pilot and data channels of each carrier is always50%.Table 3 is a summary of the primary Galileo navigation signal parameters.370HSignal nameE5E6E1ChannelE5a dataE5a pilotE5b dataE5b pilotE6-B dataE6-C pilotE1-B dataE1-C pilotModulationTypeAltBOC(15,10)Chip Rate[Mcps]Symbol Rate[sps]10.23BPSK(5)5.115BOC(1,1)1.023User min. received powerabove 10° elevation [dBW](based on an ideallymatched and isotropic 0dBi antenna and losslessatmosphere)50N/A250N/A1000N/A250N/A-155-155-155-157Table 3: Primary Galileo Navigation Signal ParametersThe Galileo terrestrial user’s maximum received signal power level is, using the sameassumptions as for the minimum received power, not expected to exceed 3 dB above thecorresponding minimum received power.For purposes of establishing user receiver dynamic range for receiver design and test, themaximum received signal power level is not expected to exceed 7 dB above thecorresponding minimum received power.©, 2006, European Space Agency / Galileo Joint UndertakingDocument subject to terms of use and disclaimers p.
2-4.Reference:Issue:Revision:Date:GAL OS SIS ICD/D.0Draft023/05/2006Page237. GALILEO SIGNALS CHARACTERISTICSThe Galileo Signal in Space (SIS) comprises signals modulated onto three separate carriers:The E5-, E6- and E1-Signal.The following Table 4 defines the signal parameters used in this chapter, with the indices:371H••‘X’ accounting for the respective carrier (E5, E5a, E5b, E6 or E1) and‘Y’ accounting for the respective signal component or signal channel (B, C, I or Q)within the signal ‘X’.ParameterfXPXLX-YTC,X-YTS,X-YTD,X-YRC,X-YRS,X-YRD,X-YSX(t)CX-Y(t)DX-Y(t)scX-Y(t)eX-Y(t)BBBBBBBBBBBBBBBBBBBBBBBBBBBBExplanationCarrier frequencyRF-Signal powerRanging code repetition periodRanging code chip lengthSubcarrier periodNavigation message symbol duration= 1/ TC,X-Y; code chip rate= 1/ TS,X-Y; Subcarrier frequency= 1/ TD,X-Y; Navigation message symbol rateSignal pass-band representationBinary (NRZ modulated) ranging codeBinary (NRZ modulated) navigation message signalBinary (NRZ modulated) subcarrierBinary NRZ modulated navigation signal componentincluding code, sub-carrier (if available) and navigationmessage data (if available); ( = CX-Y(t) ⋅ scX-Y(t) ⋅ DX-Y(t));UBUBBBBBBsX(t)BBBBBBBBBBBBBBBBBBNormalised baseband signal (=sX-I(t) + j⋅ sX-Q(t)) (unitmean power)‘kth’ Chip of the ranging code‘kth’ Symbol of the navigation message= TD,XY / TC,XY; number of code chips per symbol‘i’ modulo LInteger part of i/DCFunction “rectangle”, which is equal to 1 for 0<t<T, andequal to 0 elsewhereTable 4: Signal description parametersBcX-Y,kdX-Y,kDCX-Y|i|L[i]DCrectT(t)BPPPPBPBPPPBPBBP©, 2006, European Space Agency / Galileo Joint UndertakingDocument subject to terms of use and disclaimers p.
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