iSXblue/SXBlue II GNSS Series Technical Reference Manual
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2.4
COAST
™
, G-Dif
™
and SureTrack
™
Technologies
The iSXBlue/SXBlue II is packed with features that make it unique on the market. Coast and G-Dif
technologies affect positively the submeter performance of the receiver, whereas SureTrack is related to
the RTK performance.
•
The iSXBlue/SXBlue II receiver incorporates the
COAST
TM
technology that allows it to operate
with old correction data for up to 35 to 40 minutes or more without significant accuracy
degradation. The feature’s performance is attributed to sophisticated algorithms that are able to
anticipate how errors change during a period of correction loss.
Traditional receiver technology would experience an increasing degradation with increasing age
of corrections, resulting in less than adequate performance over a shorter period of time. COAST
technology provides more consistent positioning during periods when signal loss occurs, thus
bridging the gap to when the signal is reacquired. This means that the iSXBlue/SXBlue II is more
tolerant than competing products to loss of SBAS or externally input RTCM SC-104 corrections.
•
The
G-Dif
feature allows the iSXBlue/SXBlue II (with GLONASS) to use GLONASS with GPS-
only corrections. For example, all SBAS (besides, eventually, the Russian SDCM) only broadcast
corrections for GPS satellites and contain no GLONASS correctors. When tracking an SBAS
signal, the iSXBlue/SXBlue II GNSS will use its DGPS solution along with other parameters to
generate its own GLONASS corrections. This unique feature of using all satellites in view,
provides with the advantages of all the extra GLONASS observations required in tough and
challenging conditions.
•
The
SureTrack
technology is the same as the G-Dif but for carrier phase RTK corrections (as
opposed to code-phase). SureTrack feature, as for the G-Dif only applies to the GNSS models.
With SureTrack technology the RTK rover makes use of every satellite it is tracking, even
satellites not tracked at the base. This results in fewer RTK dropouts in congested environments,
faster reacquisitions and more robust solutions due to better cycle slip detection. SureTrack also
removes concerns with using various manufacturers GNSS base. Even if the GNSS base delivers
L1/L2 GPS, SureTrack with GLONASS at the rover will deliver the RTK performance
2.5
Real-Time Differential Options
Real-time differential options can be added to your iSXblue/SXBlue II receiver. These options are made
available depending on the installed firmware and the subscription/activation. Up to two firmware
applications can be installed on the receiver and the user can switch from one to the other to select the
proper differential mode. See Chapter 3 for more information on firmware architecture and activating
options (RTK Base, RTK Rover, Auto-Dif, GLONASS and 20Hz).
There are three (3) firmware applications available for the SXBlue II family and each of them allows
various differential modes:
•
Multi-Function Application, called the
MFA
: SBAS, DGPS input (RTCM 2.x), RTK Rover
(inputs RTCM 3.x, CMR, CMR+), RTK Base (outputs RTCM 3.x, CMR) and OmniSTAR L-
Band (supports VBS, XP, HP and G2).
•
SBAS/RTK Base Application
(SBASRTKB)
: SBAS, DGPS input (RTCM 2.x), RTK Base
(outputs RTCM 3.x, CMR) and OmniSTAR L-Band (supports VBS, XP, HP and G2).