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FIBOCOM NL668-LA Series Hardware Guide
Page 46 of 61
7.4 GNSS Receiver
7.4.1 GNSS Specification
NL668-LA series module (except NL668-LA-01, NL668-LA-31-90) supports GNSS function and adopts
Qualcomm Gen8 technology, its specification show as follows:
Table 7-5 GNSS specification
Description
Condition
Typ.
Power
(
AT+CFUN=0
)
GNSS
fixing
62mA
GNSS tracking
62mA
Standby
34mA
TTFF
GNSS
Cold start
45s
Warm start
40s
Hot Start
5s
Sensitivity
Acquisition
-144dbm
Tracking
-155dbm
CN0
GNSS Signal@-130dBm
38.5 dB-Hz
Positional accuracy
CEP
GNSS Signal@-130dBm
<3.5m
7.4.2 GNSS Observe Protocol
NL668-LA series module adopts NMEA-0183 protocol.
7.5 Antenna Design
7.5.1 Antenna Index
1) Antenna efficiency
Antenna efficiency is the ratio of antenna input power to radiated power. Due to the antenna return loss,
material loss, and coupling loss, the radiated power is always lower than the input power.
Recommended > 40% (-4dB).
2) S11 or VSWR
S11 shows that the matching degree of the antenna’s 50
Ω
impedance, to a certain extent, affects the
antenna efficiency. VSWR test methods can be used to measure this parameter. Recommended S11 <
-10dB.
3) Polarization
Polarization is the rotation direction of the electric field in the maximum radiation direction of the antenna.