C.2 Multi-path case
38.1713GPPNRRelease 17Requirements for Support of Assisted Global Navigation Satellite System (A-GNSS)TS
Doppler frequency difference between direct and reflected signal paths is applied to the carrier and code frequencies. The Carrier and Code Doppler frequencies of LOS and multi-path for GNSS signal are defined in table C.1.
Table C.1: Multipath case
|
Initial relative delay |
Carrier Doppler frequency of tap [Hz] |
Code Doppler frequency of tap [Hz] |
Relative mean power [dB] |
|
0 |
Fd |
Fd / N |
0 |
|
X |
Fd – 0.1 |
(Fd-0.1) /N |
Y |
|
NOTE: Discrete Doppler frequency is used for each tap. |
|||
Where the X and Y depends on the GNSS signal type and is shown in Table C.2, and N is the ratio between the transmitted carrier frequency of the signals and the transmitted chip rate as shown in Table C.3 (where k in Table C.3 is the GLONASS frequency channel number).
Table C.2: Parameter values
|
System |
Signals |
X [m] |
Y [dB] |
|
BDS |
B1I |
75 |
-4.5 |
|
B1C |
125 |
-4.5 |
|
|
B2a |
15 |
-6 |
|
|
B3I |
15 |
-6 |
|
|
Galileo |
E1 |
125 |
-4.5 |
|
E5a |
15 |
-6 |
|
|
E5b |
15 |
-6 |
|
|
GLONASS |
G1 |
275 |
-12.5 |
|
G2 |
275 |
-12.5 |
|
|
GPS/Modernized GPS |
L1 C/A |
150 |
-6 |
|
L1C |
125 |
-4.5 |
|
|
L2C |
150 |
-6 |
|
|
L5 |
15 |
-6 |
Table C.3: Ratio between carrier frequency and chip rate
|
System |
Signals |
N |
|
BDS |
B1I |
763 |
|
B1C |
1540 |
|
|
B2a |
115 |
|
|
B3I |
124 |
|
|
Galileo |
E1 |
1540 |
|
E5a |
115 |
|
|
E5b |
118 |
|
|
GLONASS |
G1 |
3135.03 + k ⋅ 1.10 |
|
G2 |
2438.36 + k ⋅ 0.86 |
|
|
GPS/Modernized GPS |
L1 C/A |
1540 |
|
L1C |
1540 |
|
|
L2C |
1200 |
|
|
L5 |
115 |
The initial carrier phase difference between taps shall be randomly selected between 0 and 2. The initial value shall have uniform random distribution.
Annex D (normative):
Measurement sequence chart