User's Manual

LTE Module
EC20 Hardware Design
EC20_Hardware_Design Confidential / Released 46 / 83
4 GNSS Receiver
4.1. General Description
EC20 includes a fully integrated global navigation satellite system solution that supports gpsOne Gen8A
of Qualcomm (GPS and GLONASS). Compared with GPS only, dual systems increase usable
constellation, reduce coverage gaps and TTFF, and increase positioning accuracy, especially in rough
urban environments.
EC20 works in standalone mode, allows device to demodulate GNSS assistance data, calculate position
without any assistance from the network, and suitable for various application needing lowest-cost,
accurate position determination. EC20 supports Qualcomm gpsOneXTRA technology (one kind of
A-GNSS), which can download XTRA file from the internet server to enhance the TTFF. XTRA file
contains predicted GPS and GLONASS satellites coordinates and clock biases valid for up to 7days. It is
the best if XTRA file is downloaded every 1-2 days. And EC20 also supports SBAS (including WAAS,
EGNOS and MSAS), which will improve fix accuracy.
EC20 provides power-saving solution named DPO (Dynamic Power Optimization), which attempts to turn
off GNSS RF parts, reduces current consumption by 50% at most without impact on TTFF, thus extends
battery life, and maximizes talk and standby time as well.
EC20 supports standard NMEA-0183 protocol, and outputs NMEA sentences with 1Hz via USB interface
by default.
By default, EC20 GNSS engine is switched off, it has to be switched on with AT command. For more
details about GNSS engine technology and configurations, please refer to document [3].