Galileo OS SIS ICD (797928), страница 6
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2-4.BBUnitHzWchipssssHzHzHzReference:Issue:Revision:Date:GAL OS SIS ICD/D.0Draft023/05/2006Page247.1 MODULATIONIn the following sections, modulation expressions are given for the power normalizedcomplex envelope (i.e. base-band version) s(t) of a modulated (band-pass) signal S(t). Bothare described in terms of its in-phase and quadrature components by the following genericexpressions in Eq. 1:372H[]S X (t ) = 2 ⋅ PX ⋅ s X − I (t ) ⋅ cos(2π f X t ) − s X −Q (t ) ⋅ sin (2π f X t ) ,Eq. 1s X (t ) = s X − I (t ) + j ⋅ s X −Q (t )with the parameters according to Table 4.37H7.1.1 E5 Signal7.1.1.1 Modulation SchemeThe diagram in Figure 4 provides a generic view of the E5 signal modulation.374HCE5a-I (t)F/NAV:DE5a-I (t)CE5a-Q (t)AltBOCsE5(t)CE5b-I (t)I/NAV:DE5b-I (t)CE5b-Q (t)Figure 4: Modulation scheme for the E5 signalThe E5 signal components are generated according to the following:• eE5a-I from the F/NAV navigation data stream DE5a-I modulated with the unencryptedranging code CE5a-I• eE5a-Q (pilot channel) from the unencrypted ranging code CE5a-Q• eE5b-I from the I/NAV navigation data stream DE5b-I modulated with the unencryptedranging code CE5b-I• eE5b-Q (pilot channel) from the unencrypted ranging code CE5b-QBBBBBBBBBBBBBBBBBBBThe respective definitions are following (Eq.
2):375H©, 2006, European Space Agency / Galileo Joint UndertakingDocument subject to terms of use and disclaimers p. 2-4.Be E 5 a − I (t ) =eE 5 a −Q (t ) =eE 5b − I (t ) =eE 5b −Q (t ) =+∞∑ ⎡⎢⎣cE 5a − I , ii = −∞LE 5 a − I+∞∑ ⎡⎢⎣cE 5a −Q , ii = −∞LE 5 a −Q⋅ d E 5a − I ,[i ]DCE 5 a−IReference:Issue:Revision:Date:GAL OS SIS ICD/D.0Draft023/05/2006Page25rectTC ,E 5 a−I (t − i ⋅ TC , E 5 a − I )⎤⎥⎦⋅ rectTc ,E 5 a−Q (t − i ⋅ TC , E 5a −Q )⎤⎥⎦Eq. 2∑ ⎡⎢cE 5b − I , i LE 5b−I ⋅ d E 5b − I ,[i ]DCE 5b−I rectTC ,E 5b−I (t − i ⋅ TC , E 5b − I )⎤⎥⎦i = −∞⎣+∞+∞∑ ⎡⎢⎣cE 5b −Q , ii = −∞LE 5 b−Q⋅ rectTC ,E 5b−Q (t − i ⋅ TC , E 5b −Q )⎤⎥⎦The Galileo satellites transmit ranging codes for E5 signal components with the chip- andsubcarrier- rates stated in the following Table 5.376HSignal(Parameter X)ChannelSubcarrier-rateRanging code chip-rate(Parameter Y)RS,X-Y [MHz]RC,X-Y [MChip/s]INo subcarrier10.230QNo subcarrier10.230INo subcarrier10.230QNo subcarrier10.230Table 5: E5 chip rates and subcarrier ratesBE5aE5bBBBThe Navigation Data Message streams after channel encoding are transmitted for E5 signalcomponents with the symbol rates as stated in the following Table 6.37HSignal(Parameter X)E5aE5bChannelSymbol-rate(Parameter Y)RD,X-Y [symbols/s]I50QNo data (‘pilot channel’)I250QNo data (‘pilot channel’)Table 6: E5 symbol ratesBB7.1.1.2 Modulation TypeThe wideband E5 signal is generated with the AltBOC modulation of side-band sub-carrierrate RS,E5 = 1/TS,E5 = 15.345 MHz (15 x 1.023 MHz) according to the expression in Eq.
3:BBBB©, 2006, European Space Agency / Galileo Joint UndertakingDocument subject to terms of use and disclaimers p. 2-4.378Hs E5 (t ) =12⋅ 212⋅ 212⋅ 212⋅ 2Reference:Issue:Revision:Date:GAL OS SIS ICD/D.0Draft023/05/2006Page26⋅ (e E5a −I (t ) + j ⋅ e E5a −Q (t )) ⋅ [sc E5 −S (t ) − j ⋅ sc E5 −S (t − Ts,E5 4 )] +⋅ (e E5b −I (t ) + j ⋅ e E5b −Q (t )) ⋅ [sc E5 −S (t ) + j ⋅ sc E5 −S (t − Ts,E5 4 )] +Eq.
3⋅ (eE5a −I (t ) + j ⋅ eE5a −Q (t )) ⋅ [sc E5 −P (t ) − j ⋅ sc E5−P (t − Ts,E5 4 )] +⋅ (eE5b −I (t ) + j ⋅ eE5b −Q (t )) ⋅ [sc E5 −P (t ) + j ⋅ sc E5 −P (t − Ts,E5 4 )] .with the binary signal components eE5a-I, eE5a-Q, eE5b-I and eE5b-Q (consisting of the BPSKmodulated ranging codes multiplied with the respective navigation data stream for the datachannels) as defined in Eq. 2.
The respective dashed signal components ēE5a-I, ēE5a-Q, ēE5b-I andēE5b-Q represent product signals according to Eq. 4:BBBBBBBB379HBBBBBBBB380HeE5a−I = e E5a −Q ⋅ e E5b −I ⋅ e E5b−Q ,eE5b −I = e E5b −Q ⋅ e E5a −I ⋅ e E5a −Q ,eE5a −Q = e E5a −I ⋅ e E5b −I ⋅ e E5b −Q ,eE5b −Q = e E5b −I ⋅ e E5a −I ⋅ e E5a −Q .Eq. 4The parameters scE5-S and scE5-P represent the four valued sub-carrier functions for the singlesignals and the product signals respectively:BBBsc E 5− S (t ) =B∞∑ AS ii = −∞8⋅ rectTS ,E 5 / 8 (t − i ⋅ Ts , E 5 8)andsc E 5− P (t ) =∞∑ APii = −∞8Eq. 5⋅ rectTS ,E 5 / 8 (t − i ⋅ Ts , E 5 8)with the coefficients ASi and APi according to the following Table 7.Bi2 ⋅ ASiB2 ⋅ APiBBBBBB381H012345672 +11-1− 2 −1− 2 −1-112 +11-1-11− 2 +12 −12 −1− 2 +1Table 7: AltBOC subcarrier coefficientsOne period of the subcarrier functions scE5-S and scE5-P is shown in the following Figure 5.BBBB©, 2006, European Space Agency / Galileo Joint UndertakingDocument subject to terms of use and disclaimers p.
2-4.382H( 2 +1)2Reference:Issue:Revision:Date:GAL OS SIS ICD/D.0Draft023/05/2006Page27AltBOC scE5-s(t)1AltBOC scE5-p(t)122 −1 20− 2 −1 2−1 2-( )( )−1− 2 +1 2( )0¼½t / TS,E5¾1Figure 5: One period of the two subcarrier functions involved in AltBOC modulationThe relative power of the product-signals within the unfiltered base-band signal sE5(t) is(B)B⎡ 2 − 1 + 1⎤ 8 ≈ 15% .⎥⎦⎢⎣2Equivalently, the AltBOC complex baseband signal sE5(t) can be described as an 8-PSKsignal,B⎛ π⎞s E 5 (t ) = exp⎜ j k (t )⎟ with⎝ 4⎠BEq.
6k (t )∈ {1,2,3,4,5,6,7,8},and the corresponding phase states illustrated in the following Figure 6.38HQ213845I76Figure 6: 8-PSK phase-state diagram of E5 AltBOC signal©, 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.0Draft023/05/2006Page28The relation of the 8 phase states to the 16 different possible states for the quadruple eE5a-I(t),eE5a-Q(t), eE5b-I(t), and eE5b-Q(t) depends also on time. Therefore, time is partitioned first in subcarrier intervals Ts,E5 and further sub-divided in 8 equal sub-periods.
The index iTs of theactual sub-period is given by:BBBBBBBBBBB⎡ 8⎤i Ts = integer part ⎢⋅ (t modulo Ts,E5 )⎥⎣⎢ Ts,E5⎦⎥with i Ts ∈ {0,1,2,3,4,5,6,7}BEq. 7and determines which relation between input quadruple and phase states has to be used.The dependency of phase-states from input-quadruples and time is given in the followingTable 8.384HeE5a-IeE5b-IeE5a-QeE5b-Qt’ = t modulo Ts,E5iTst’0 [0,Ts,E5/8[1 [Ts,E5/8, 2⋅ Ts,E5/8[BBBBBBBBBBInput Quadruples-1 -1 -1 -1-1 -1 -1 -1-1 -1 11-1 1 -1 1-11-1-1-11-11-111-1-11111-1-1-11-1-111-11-11-11111-1-111-11111-11111k (according to sE5 (t ) = exp( jk π 4) )BBBBBBBB544363126572788154832312657674812[2⋅ Ts,E5/8, 3⋅ Ts,E5/8[14872312657634853[3⋅ Ts,E5/8, 4⋅ Ts,E5/8[18872316257634454[4⋅ Ts,E5/8, 5⋅ Ts,E5/8[18872756213634455[5⋅ Ts,E5/8, 6⋅ Ts,E5/8[18476756213238456[6⋅ Ts,E5/8, 7⋅ Ts,E5/8[58436756213278417[7⋅ Ts,E5/8, Ts,E5 [5443675261327881BBBBBBBBBBBBBBBBBBBBBBBBTable 8: Look-up table for AltBOC phase states in dependency ofinput quadruples and time7.1.2 E6 Signal7.1.2.1 Modulation SchemeThe diagram in the following Figure 7 provides a generic view of the E6 signal generation.385H©, 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.0Draft023/05/2006Page29DE 6 − B (t )eE 6 − B (t )C E 6− B (t )12C E 6 −C (t )s E 6 (t )eE 6 −C (t )Figure 7: Modulation scheme for the E6 signalThe E6 signal components are generated according to the following:• eE6-B from the C/NAV navigation data stream DE6-B modulated with the ranging codeCE6-B. Note: C/NAV message format is not subject of this ICD for Galileo OS.• eE6-C (pilot channel) from the ranging code CE6-CBBBBBBBBBBThe B and C components are generated according to the following Eq. 8386HeE 6 − B (t ) =eE 6 −C (t ) =+∞∑ ⎡⎢⎣cE 6− B , ii = −∞LE 6− B+∞∑ ⎡⎢⎣cE 6−C , ii = −∞LE 6−C⋅ d E 6 − B ,[i ]DC⋅ rectTC ,E 6−B (t − i ⋅ TC , E 6 − B )⎤⎥⎦E 6− BEq. 8⋅ rectTC ,E 6−C (t − i ⋅ TC , E 6 −C )⎤⎥⎦Galileo satellites transmit ranging codes for E6 signal components with the chip rates stated inTable 9. For signal components with additional sub-carrier modulation, also the sub-carrierrates are stated in Table 9.387H38HChannel(Parameter Y)BCSubcarrier typeSubcarrier rateRS,E6-Y [MHz]BNo subcarrierNo subcarrierBRanging code chip-rateRC,E6-Y [MChip/s]5.1155.115BBTable 9: E6 chip rates and subcarrier ratesThe Navigation Data Message streams after channel encoding are transmitted for E6 signalcomponents with the symbol rates as stated in Table 10.389HChannel(Parameter Y)BCSymbol-rateRD,E6-Y [symbols/s]1000No data (‘pilot channel’)BBTable 10: E6 symbol rates©, 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.0Draft023/05/2006Page307.1.2.2 Modulation TypeThe E6 signal is generated according to Eq. 9, with the binary signal components eE6-B(t) andeE6-C(t).Note that both pilot and data channel are combined on the same carrier component.390HBBBBs E 6 (t ) =1[e2E 6− B(t ) − eE 6−C (t )]Eq. 97.1.3 E1 Signal7.1.3.1 Modulation SchemeThe diagram in Figure 8 provides a generic view of the E1 signal generation.391HscE1− C (t )DE1− B (t )eE1− B (t )CE1− B (t )12CE1−C (t )sE1 (t )eE1− C (t )scE1− C (t )Figure 8: Modulation scheme for the E1 signalThe E1 signal components are generated according to the following.• eE1-B from the I/NAV navigation data stream DE1-B, modulated with the ranging codeCE1-B and the sub-carrier scE1-B• eE1-C (pilot channel) from the ranging code CE1-C modulated with the sub-carrier scE1-CBBBBBBBBBBBBBBThe B and C components are generated according to the following Eq.
10:392HeE1− B (t ) =eE1−C (t ) =∑ [cE1− B , i L∑ [cE1−C , i L+∞i = −∞E 1− B+∞i = −∞E 1−C⋅ d E1− B ,[i ]DCE 1− B]⋅ rectTC ,E 1−B (t − i ⋅ TC , E1− B )⋅ sign [sin (2π ⋅ RS , E1− B ⋅ t )]]Eq. 10⋅ rectTC ,E 1−C (t − i ⋅ TC , E1−C )⋅ sign [sin (2π ⋅ RS , E1−C ⋅ t )]Galileo satellites transmit ranging codes for E1 signal with the chip- and subcarrier- ratesstated in Table 11.39H©, 2006, European Space Agency / Galileo Joint UndertakingDocument subject to terms of use and disclaimers p.
2-4.Channel(Parameter Y)BCSubcarriertypeBOCBOCReference:Issue:Revision:Date:GAL OS SIS ICD/D.0Draft023/05/2006Page31Subcarrier-rateRS,E1-Y [MHz]1.0231.023BBRanging code chip-rateRC,E1-Y [MChip/s]1.0231.023BBTable 11: E1 chip- and subcarrier-ratesThe Navigation Data Message streams after channel encoding are transmitted for E1 signalcomponents with the symbol rates as stated in Table 12.394HChannel(Parameter Y)BCSymbol-rateRD,E1-Y [symbols/s]250No data (‘pilot channel’)BBTable 12: E1 symbol rates7.1.3.2 Modulation TypeThe E1 composite signal is generated according to Eq.
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