Specifications

VP ONCORE COMMAND REFERENCE
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CORRECTION THRESHOLDS (@@AD)
This command allows the control of two timer thresholds that affect the
following:
• the "smoothness" of the position fix (FlX_THR), and
• the "smoothness" of the differential correction output (OUT_THR).
The Motorola VP Oncore GPS receiver filters the noisy raw code phase
measurements with the very smooth carrier phase measurements. This
filtering process begins as soon as the signal is acquired and continues
as long as the signal is tracked. The filter bandwidth is narrowed
gradually and reaches its final state after 128 seconds. The VP Oncore
keeps a filter timer for each channel to control the timing of the
bandwidth changes. The filter bandwidth is reset to its initial wide setting
and the timer is set to zero whenever the signal is lost.
The user-controllable threshold OUT_THR can be used to gate a
channel's output of differential corrections until it has had some user-
defined adequate time to filter the raw code phase. Earlier versions of
the Oncore software used 32 as an internal threshold for this parameter.
There is an inherent interdependence in the use of these two thresholds.
For instance, if FIX_THR is set to 16 and OUT_THR is set to 8, then the
receiver will filter the raw code phase for 16 seconds before using that
channel for fix and then will immediately output differential corrections for
that channel (if the message has been requested). The 8-second
OUT_THR threshold is effectively overridden by the 16 second FIX_THR
threshold in this example.
Default values: FIX_THR = 0
OUT_THR = 32
19 Synergy Systems, LLC 05OCT01