Leica GR10 Operational Manual page 139

Initialize measurement
engine
SBAS note
For SBAS logging, the following behaviour will be seen:
Event log shows a complete loss of lock message when no SBAS data is tracked.
MDB and RINEX logging will always log the current SBAS observations when activated.
NMEA position output shows the following
SBAS is off
SBAS use for DGPS is on
SBAS use for DGPS satellite is lost
SBAS use for DGPS satellite
become available
Background information on external oscillators
An unsteered oscillator can be approximated by a three-state clock model, with two states representing the range bias and
range bias rate, and a third state assumed to be a Gauss-Markov (GM) process representing the range bias error generated
from satellite clock dither. The third state is included because the Kalman filter assumes an (unmodeled) white input error. The
significant correlated errors produced by satellite clock dither are obviously not white and the Markov process is an attempt to
handle this kind of short term variation.
The internal units of the new clock model's three states (offset, drift and GM state) are metres, metres per second and metres.
When scaled to time units for the output log, these become seconds, seconds per second and seconds, respectively. Note that
the old units of the third clock state (drift rate) were metres per second per second.
The user has control over 3 process noise elements of the linear portion of the clock model. These are the h
elements of the power law spectral density model used to describe the frequency noise characteristics of oscillators:
where f is the sampling frequency and Sy(f) is the clock's power spectrum. Typically only h, and h
variance and the clock model's process noise elements.
Before you use an optional external oscillator, several clock model parameters must be set. There are default settings for a
Temperature-Compensated Crystal Oscillator (TCXO), ovenized crystal oscillator (OCXO), Rubidium and Cesium standard.
When using a Hydrogen-Maser you can either use the default values of the clock parameters or choose to use customized
settings
Clock parameters - Default values
The restore default button fills all fields with the default values and
stores these values. Pressing the save button is not necessary. When
accepting the confirmation message, all settings on this page are
overwritten with the default settings.
This button redirects you to the Tools page where you can re-initialize the measurement
engine. Then all ephemeris and almanac data will be deleted and the position
computation will be restarted.
Description
Navigated position.
Differential code position.
Last position before SBAS data was lost for 60s then reset to navigated position.
Differential code position.
6: Context sensitive help
, h and h
0 -1 -2
affect the clock's Allan
-2
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