Data Sheet

ZOE-M8 - Data Sheet
UBX-16008094 - R07 Production Information Functional description
Page 9 of 29
1.6.3 AssistNow™ Autonomous
AssistNow Autonomous provides aiding information without the need for a host or external network connection.
Based on previous broadcast satellite ephemeris data downloaded to and stored by the GNSS receiver, AssistNow
Autonomous automatically generates accurate predictions of satellite orbital data (“AssistNow Autonomous data”)
that is usable for future GNSS position fixes. The concept capitalizes on the periodic nature of GNSS satellites; by
capturing strategic ephemeris data at specific times of the day.
u-blox’s AssistNow Autonomous benefits are:
• Faster fix in situations where GNSS satellite signals are weak
• No connectivity required
• Compatible with AssistNow Online (can work stand-alone, or in tandem with AssistNow Online service)
• No integration effort; calculations are done in the background, transparent to the user.
The ZOE-M8 SiPs utilizing external Flash can predict accurate satellite ephemeris for up to six days after
initial reception. The ROM based ZOE-M8 can use only GPS satellites with a prediction time of up to three
days.
For more information on A-GNSS, see the u-blox 8 / u-blox M8 Receiver Description Including Protocol
Specification [2].
1.7 Augmentation systems
1.7.1 Satellite-Based Augmentation System (SBAS)
The u-blox ZOE-M8 SiPs support reception of SBAS broadcast signals. These systems supplement GNSS data with
additional regional or wide area GPS augmentation data. The system broadcasts range correction and integrity
information via satellite which can be used by GNSS receivers to improve resulting precision. SBAS satellites can
be used as additional satellites for ranging (navigation), further enhancing availability. The following SBAS types
are supported: GAGAN, WAAS, EGNOS and MSAS.
For more details see the u-blox 8 / u-blox M8 Receiver Description Including Protocol Specification [2].
1.7.2 QZSS
The Quasi-Zenith Satellite System (QZSS) is a regional navigation satellite system that transmits additional GPS
L1C/A signals for the Pacific region covering Japan and Australia. The ZOE-M8 SiPs are able to receive and track
these signals concurrently with GPS signals, resulting in better availability especially under challenging signal
conditions, e.g. in urban canyons. The L1-SAIF signal provided by QZSS can be enabled for reception via a GNSS
configuration message.
1.7.3 IMES
The Japanese Indoor Messaging System (IMES) system is used for indoor position reporting using low-power
transmitters which broadcast a GPS–like signal. The ZOE-M8 SiPs can be configured to receive and demodulate
the signal to provide an in-door location estimate.
This service is authorized and available only in Japan.
IMES reception is disabled by default
1.7.4 Differential GPS (D-GPS)
u-blox ZOE-M8 SiPs support Differential-GPS (D-GPS) data according to RTCM specification 10402.3 [4]:
"RECOMMENDED STANDARDS FOR DIFFERENTIAL GNSS". The use of Differential-GPS data improves GPS position
accuracy. The RTCM implementation supports the following RTCM 2.3 messages: