IS-GPS-800A - US Coast Guard Navigation Center

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chipping rate of 1.02299999954326 MHz. The nominal carrier frequency (f 0 ) – as it appears to an observer on theground – shall be 1575.42 MHz.The requirements specified in this IS shall pertain to the signal contained within a 30.69 MHz bandwidth centeredabout the L1 nominal frequency.The L1C signal shall utilize a modulation technique of BOC (f s , 1) which specifies a subcarrier frequency of f s ×1.023 MHz and a spreading code chipping rate of 1 × 1.023 MHz = 1.023 MHz.3.2.1.2 Signal PolarizationThe transmitted signal shall be Right-Hand Circularly Polarized (RHCP). For an angular range of 13.8 degreesfrom nadir, the L1 ellipticity shall be no worse than 1.8 dB.3.2.1.3 Carrier Phase Noise (TBR)The phase noise spectral density of the unmodulated carrier shall not exceed the magnitude of a straight line (on alog-log plot) between -30 dBc/Hz at 1 Hz and -70 dBc/Hz at 1 x 10^4Hz, and the one-sided integrated phase noisespectrum between 1 Hz and 10 kHz shall not exceed 0.01 radians rms.Or,The phase noise spectral density of the unmodulated carrier shall be such that an approximation to the third orderJaffe-Rechtin phase lock loop, which has a 10 Hz one-sided loop noise bandwidth, shall be able to track the carrierto an accuracy of 0.01 radians rms.3.2.1.4 Spurious TransmissionsIn-band spurious transmissions, from the SV, shall be at or below -40 dBc over the band specified in 3.2.1.1. Inbandspurious transmissions are defined as transmissions within the band specified in 3.2.1.1 which are notexpressly components of the L1 signal.3.2.1.5 Correlation LossCorrelation loss is defined as the difference between the SV power received in the bandwidth defined in 3.2.1.1 andthe signal power recovered in an ideal correlation receiver of the same bandwidth using an exact replica of thewaveform within an ideal sharp-cutoff filter bandwidth centered at L1, whose bandwidth corresponds to thatspecified in 3.2.1.1 and whose phase is linear over that bandwidth. The correlation loss apportionment due to SVmodulation and filtering imperfections shall be 0.2 dB maximum.3.2.1.6 Signal Component Phasing3.2.1.6.1 Phase RelationshipCarriers of the two L1C components defined in Section 3.1 shall be in the same phase within ±100 milliradians.4 IS-GPS-800A8 June 2010
Carriers of the two L1C components shall be in the same phase (within ±100 milliradians) as the P(Y)-code carrier.See IS-GPS-200 for phase relationships to other L1 signals.3.2.1.6.2 Phase ContinuityWhile a satellite is broadcasting standard L1C P code and standard L1C D code signals with data which indicates L1Csignal health is OK, there will not be any commanded operation causing an intentional phase discontinuity. Thisdoes not apply to phase discontinuities caused by signal modulation. Phase discontinuities are subject to therequirements of 3.2.1.6.1.3.2.1.7 Signal Characteristics3.2.1.7.1 Signal CoherenceAll transmitted signals for a particular SV shall be coherently derived from the same on-board frequency standard.On the L1 carrier, the chip transitions of the two modulating signals, L1C D and L1C P , shall be such that the averagetime difference between them (i.e. L1C D /L1C P ), and between each and the transitions of L1P(Y) (i.e. L1C D /L1P(Y),L1C P /L1P(Y)), do not exceed 10 nanoseconds. The variable time difference shall not exceed 1 nanosecond (95%probability), when including consideration of the temperature and antenna effect changes during a vehicle orbitalrevolution. Corrections for the bias components of the time difference are provided to the US in the CNAV-2message using parameters designated as ISCs (reference paragraph 3.5.3.9.1).3.2.1.7.2 Signal DistortionThe duration of the “+1 polarity” portions of the BOC (1, 1) code shall equal the duration of the “-1 polarity”portions of the BOC (1, 1) code within 5 nanoseconds as measured at the zero crossing point.The duration of the “+1 polarity” portions of the BOC (6, 1) code shall equal the duration of the “-1 polarity”portions of the BOC (6, 1) code within 5 nanoseconds as measured at the zero crossing point.3.2.1.8 Equipment Group DelayEquipment group delay is defined as the delay between the signal radiated output of a specific SV (measured at theantenna phase center as observed from the signal’s zero crossings) and the output of that SV's on-board frequencysource; the delay consists of a bias term and an uncertainty. The bias term is of no concern to the US since it isincluded in the clock correction parameters relayed in the navigation data, and is therefore accounted for by the usercomputations of system time. The uncertainty (variation) of this delay, as well as the group delay differential,between the reference signal and the signals of L1C, are defined in the following subsections.3.2.1.8.1 Group Delay UncertaintyThe effective uncertainty of the group delay shall not exceed 1.5 nanoseconds (95% probability).5 IS-GPS-800A8 June 2010
Page 1 and 2: IS-GPS-800A8 June 2010GLOBAL POSITI
Page 3 and 4: REVISION RECORDLTR DESCRIPTION DATE
Page 5 and 6: 3.2.3.3 Cyclic Redundancy Check ...
Page 7 and 8: LIST OF FIGURESFigure 3.2-1. Genera
Page 9 and 10: 1. INTRODUCTION1.1 ScopeThis Interf
Page 11: 3. SIGNAL REQUIREMENTSThe requireme
Page 15 and 16: 3.2.2 PRN Code CharacteristicsThe c
Page 17 and 18: The overlay codes are derived from
Page 19 and 20: 3.2-2 L1C Ranging Codes Parameter A
Page 21 and 22: GPS PRNSignal No.3.2-3 L1C O Overla
Page 23 and 24: FIXED LENGTH-10223 LEGENDRE SEQUENC
Page 25 and 26: 3.2.2.2 Non-Standard CodesThe non-s
Page 27 and 28: corresponding to MSB = 0. (A SV tra
Page 29 and 30: This code has the following charact
Page 31 and 32: 3.2.3.5 InterleavingThe 1748 encode
Page 33 and 34: 3.3 Signal ModulationThe signals mo
Page 35 and 36: Bit valueL1C DbitstreamSubcarrier s
Page 37 and 38: 3.5 Message DefinitionAs shown in F
Page 40 and 41: DIRECTION OF DATA FLOW FROM SV100 B
Page 46 and 47: 3.5.3 Subframe 2Subframe 2 provides
Page 48 and 49: Table 3.5-1. Subframe 2 Parameters
Page 50 and 51: 3.5.3.1 Transmission Week NumberBit
Page 52 and 53: 3.5.3.6 Ephemeris Parameter Charact
Page 54 and 55: Table 3.5-2. Elements of Coordinate
Page 56 and 57: The user shall use the broadcast UR
Page 58 and 59: where, ISC L1CD is provided to the
Page 60 and 61: 3.5.3.10.1 Integrity Status Flag (I
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The ionospheric data shall be updat
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3.5.4.2.3 User Algorithm for Applic
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transmitted by the SVs will degrade
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Table 3.5-7.Midi Almanac Parameters
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MSBCDC = Clock Differential Correct
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3.5.4.5 Subframe 3, Page 6 - TextSu
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5. RESERVED66 IS-GPS-800A8 June 201
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LSF - Leap Seconds FutureL1C - Comm
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Table 6.2-1.Legendre Sequence (Octa
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Table 6.2-2 LDPC Submatrix A for Su
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Table 6.2-3. LDPC Submatrix B for S
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Table 6.2-7. LDPC Submatrix T for s
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Table 6.2-7. LDPC Submatrix T for s
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Table 6.2-8. LDPC Submatrix A for s
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Table 6.2-8. LDPC Submatrix A for s
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Table 6.2-9. LDPC Submatrix B for S
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Table 6.2-13. LDPC Submatrix T for
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Table 6.2-16. Number of 1’s in LD
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6.3 Supporting Material6.3.1 Additi
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Table 6.3-1 Additional L1C Ranging
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PRNSignalNo.Table 6.3-2. Additional
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PRNSignalNo.Table 6.3-2 Additional
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IS-GPS-800A - US Coast Guard Navigation Center

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