SL871 Family Product User Guide
1VV0301170 Rev. 9
Page 19 of 89
2021-07-15
Not Subject to NDA
4.
PRODUCT FEATURES
Multi-Constellation
Navigation
(SL871 and SL871L only)
GPS and GLONASS constellations are enabled by default. If BeiDou is enabled, GLONASS
and Galileo are disabled.
The user may enable or disable constellations via the $PMTK353 command
The SL871-S and SL871L
–
S support GPS only.
Quasi-Zenith Satellite System (QZSS)
The satellites of the Japanese regional SBAS are in a highly inclined, elliptical
geosynchronous orbit, allowing continuous high-elevation coverage over Japan using
only three satellites plus one geostationary satellite. PRNs 193, 194, and 195 are
supported. They provide ranging signals for augmentation of the GPS system.
QZSS constellation usage is controlled by the $PMTK352 command and is disabled by
default.
NMEA reporting for QZSS may be enabled/disabled by the $PMTK351 command.
Satellite-Based Augmentation System (SBAS)
SBAS is not supported on the current production SL871L-S modules (with the enhanced
ROM).
The receiver is capable of using SBAS satellites as a source of differential corrections.
These systems (WAAS, EGNOS, GAGAN and MSAS) use geostationary satellites to
transmit signals similar to those of GPS in the same L1 band.
Enabling the SBAS feature limits the maximum fix rate to 5 Hz. If disabled, the maximum
is 10 Hz.
The module is enabled for SBAS by default, but can be disabled by command $PTMK313.
Either SBAS or DGPS corrections can be used and are set by the $PMTK301 command.
SBAS Corrections
The SBAS satellites transmit a set of differential corrections to their respective regions.
The use of SBAS corrections can improve positioning accuracy.
