Dual Automatic Mode - ashtech DG16 Reference Manual

you move from one coverage area to another. The automatic selection uses
both SBAS channels. Channel 1 tracks the best available SBAS signal and
Channel 2 scans for another available SBAS satellite signals, maintaining a
SBAS satellite directory in a battery-backed memory. The quality of the SBAS
satellite tracked on Channel 1 (signal strength, elevation, etc.) is continuously
compared to the quality threshold. When the quality of the signal on Channel
1 is less than the quality threshold, the DG16 checks the quality of the signal
of the Channel 2 satellite. If Channel 2 satellite has a better signal, the DG16
switches to it. If, on the other hand, the signal on Channel 1 drops below the
threshold and the signal on Channel 2 is no better or any SBAS satellite, the
DG16 continues to use and track the satellite on Channel 1.
Use the $PASHS,SBA,SAM command to set the receiver in Single Automatic
mode to track SBAS satellites and use the data in the navigation solution.
The best SBAS satellite is determined based collectively on the satellite SNR, elevation angle,
continuity of signal reception, etc.

Dual Automatic Mode

In Dual Automatic SBAS mode the DG16 automatically detects all available
SBAS signals and selects the best two satellites. Channel 1 tracks the best
satellite available, and Channel 2 tracks the second-best available satellite. In
this mode, the DG16 has no capability to continue to scan for other, better
SBAS signals. Therefore, once selected, the DG16 continues to track these
two selected SBAS satellites so long it is able. If the signal on one of the
channels is lost, the DG16 scans the available frequencies to find another
SBAS satellite.
Use the $PASHS,SBA,DAM command to set the receiver in Dual Automatic
mode to track two SBAS satellites and use the data in the navigation solution.
The best SBAS satellite is determined based collectively on the satellite SNR, elevation angle,
continuity of signal reception, etc.
Manual Modes of Operation
In Manual SBAS mode, the DG16 searches for and tracks the SBAS
satellite(s) you specify. You can specify either one or two SBAS satellites for
either Single Manual Mode or Dual Manual Mode.
Single Manual Mode
In Single Manual SBAS mode, the DG16 searches for and tracks the
specified SBAS satellite (PRN = xx) on Channel 1. Channel 2 automatically
searches for and tracks the best available SBAS signal. Use the
66 DG14 and DG16 Board & Sensor Reference Manual