Specifications

Operation 11
Operation
Position Mode/ALT Fix Mode
Position Mode
The receiver performs a position fix computation in four modes. The $PASHS,PMD
command is used to select the mode. Table 2.3 describes these four modes.
ALT Fix Mode
Two modes define what altitude is selected when the receiver is in altitude hold
mode. The $PASHS,FIX command can be used to select between these modes.
In mode 0, the most recent altitude is used. This is either the one entered by using the
$PASHS,ALT command or the one computed when four or more satellites are used in
the solution, whichever is most recent. If the last altitude is the one computed with
four or more satellites, it is used only if VDOP is less than the VDOP mask.
In mode 1, only the last altitude entered is used in the position fix solution.
On initial power-up, or a receiver initialization, the most recent antenna altitude is 0.
Daisy Chain Mode
The Daisy Chain mode establishes a communication link through the GPS receiver,
between a PC/handheld and a peripheral device. When the GPS receiver is in Daisy
Table 2.3: Position Modes
Mode Description
0 At least four satellites with elevation equal to or above the elevation mask are needed to
compute a position. All three polar coordinates are computed in this mode.
1 At least three satellites with elevation equal to or above the position elevation mask are
needed to compute a position. Only the latitude and the longitude are computed if three
satellites are locked and the altitude is held. If more than three satellites are locked, this
mode is similar to mode 0.
2 At least three satellites with elevation equal to or above the position elevation mask are
needed to compute a position. Only the latitude and longitude are computed, and the
altitude is always held, regardless of the number of satellites.
3 At least three satellites with elevation equal to or above the position elevation mask are
needed to compute a position. Only the latitude and longitude are computed, and the
altitude is held if only three satellites are locked. If more than three satellites are used and
the HDOP is less than specified HDOP mask, all three polar components are computed. If
HDOP is higher than the specified HDOP mask, the receiver automatically goes into the
altitude hold mode.