Gnss Receiver; Gnss Specification; Gnss Observe Protocol; Antenna Design - Fibocom NL668-LA Series Hardware Manual

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
Power
（AT+CFUN=0）
TTFF
Sensitivity
Positional accuracy

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 50Ω 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.
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FIBOCOM NL668-LA Series Hardware Guide
Condition
GNSS
GNSS tracking
Standby
Cold start
GNSS Warm start
Hot Start
Acquisition
Tracking
CN0 GNSS Signal@-130dBm
CEP GNSS Signal@-130dBm
fixing
Typ.
62mA
62mA
34mA
45s
40s
5s
-144dbm
-155dbm
38.5 dB-Hz
<3.5m
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