SEPTENTRIO PolaRx5TR, Reference Manual

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2 Operation Details
0 0.5 1 1.5 2 2.5 3 3.5 4
−0.5
0
0.5
Up Time [hours]
RxClkBias = t
Rx
−t
GNSS
[ms]
Figure 2-2:
Effect of clock steering on the clock bias (clock steering enabled at an
up time of 1 hour).
Clock steering accuracy is dependent on the satellite visibility, and it is recommended to only
enable it under open-sky conditions.
Bit 3 of the
CommonFlags
field of the
MeasEpoch
SBF block indicates whether clock steering
is active or not.
Note for the users of a GNSS constellation simulator:
When using a constellation simulator, and if the only simulated signals are the legacy L1 and
L2 GPS and GLONASS signals, make sure to set the simulation time after December 31, 2019.
The receiver time will be incorrect before that date.
For correct time determination, it is mandatory to reset the receiver before every (re)start of
the simulation.
2.4 Computation of Position, Velocity, and
Time (PVT Solution)
The receiver computes the position, velocity and time (PVT) based on the pseudoranges, the
Doppler measurements and, if applicable, the differential corrections.
The availability of the PVT depends on:
• the number of available pseudoranges and Doppler measurements, equal to the num-
ber of tracked satellites, or a subset of them as specified by the
setSatelliteUsage
command;
• the number of valid sets of broadcast ephemerides, which are needed to compute the
position, velocity, and clock bias for each tracked satellite;
• the number of valid sets of fast and long-term SBAS corrections and their age in the
case of SBAS-aided positioning;
• the number of valid differential corrections and their age in the case of DGPS/RTK po-
sitioning.
A position fix requires a minimum of 4 tracked satellites with associated ephemerides. When
a PVT solution is not available, PVT-related SBF blocks are still output with all the numeric
fields set to Do-Not-Use values, and with the
Error
field set to indicate the source of the
problem.
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