NorthStar 2201 Installation Manual page 17

WAAS/beacon differential
Dead-reckoning mode
Fault mode
2201 INSTALLATION MANUAL, Revision B
Differential 2-D mode
The 2201 operates in differential 2-D mode when it receives
data from only three satellites with adequate geometry and
WAAS or external radiobeacon differential corrections. This is
the navigation mode with the highest performance when
differential 3-D mode can't be used.
3-D Nav mode
The 2201 operates in 3-D nav mode when it receives data from
at least four satellites with adequate geometry, but no
differential corrections. This is the preferred navigation mode
when sufficient WAAS or external radiobeacon differential
corrections aren't available.
The 941/951/952 has four options for setting the binary 2201's
WAAS and radiobeacon differential operations:
mode
•
auto (the default setting) - for automatically using WAAS,
but the 2201 will revert to beacon differential if WAAS
becomes unavailable and external beacon corrections are
applied through the port.
•
WAAS - forces WAAS only
•
radiobeacon - forces beacon differential only
• disabled - turns off differential corrections
After connecting the 941/951/952 with the 2201, to select one
of these options, see "SECTION FOUR Using WAAS with
Northstar's 941/951/952" beginning on page 25.
For information on using the 2201 with external SC104 data,
contact the Northstar Service Department.
The 2201 enters dead-reckoning mode when navigation mode
can't be maintained. The speed and direction are assumed
constant, based on the last-known data, to allow the 2201 to
provide an estimated position.
The 2201 enters fault mode if it determines that the its outputs
are affected by one or more critical system faults. This mode
supersedes all others and remains active until the next
power-down/power-up cycle. Fault mode can be entered from
any other mode (except initialization) whenever an
unrecoverable fault is detected. Fault mode prevents inaccurate
data from being transmitted.
SECTION ONE Introduction
Page 9