Moog Crossbow GNAV540 - Manual (Page 33)

GNAV540 User Manual
7430‐0808‐01 Rev. B Page 33
Setting Def e ault Valu Comments
Orientation See Figure 4 on
page 24. To configure the axis orientation, select the desired measurement for each axis:
NAV‐VIEW 2.2 will show the corresponding image of the unit, so it easy to
visualize the mode of operation. Refer to Orientation Field on page 86 for the
ints the twenty four possible orientation settings. The default setting po
connector AFT.
Freely
Integrate OFF The Freely Integrate setting allows a user to turn the unit into a free gyroscope. In
free gyroscope mode, the roll, pitch and yaw are computed exclusively from
angular rate with no Kalman filter based corrections of roll, pitch, and yaw. When
turned on, there is no coupling of acceleration based signals into the roll and
pitch or magnetometer based signal to the yaw. As a result, the roll, pitch, and
yaw outputs will drift roughly linearly with time due to sensor bias. For best
performance, the Freely Integrate mode should be used after the algorithm has
initialized. This allows the Kalman Filter to estimate the roll and pitch rate
sens
gyro or bias prior to entering the free gyroscope mode. Upon exiting the free
scope mode (OFF), one of two behaviors will occur
ƒ If the unit has been in freely integrate mode for less than sixty seconds, the
algorithm will resume operation at normal gain settings
ƒ If the unit has been in freely integrate mode for greater than sixty seconds,
the algorithm will force a reset and reinitialize with high gains automatically.
Use GPS ON The Use GPS setting enables turning on and off the GPS feedback. The default
setting is ON. When Use GPS is turned OFF, the unit’s behavior will revert to that
of AHRS Function.
Stationary
Yaw Lock
OFF This setting defaults to OFF; it is recommended to be OFF for NAV Function. The
stationary yaw lock is only recommended for consideration when the unit is
operating with GPS (Use GPS = ON) and WITHOUT magnetometer feedback (Use
Mags = OFF). Stationary yaw lock may be appropriate if the user platform is a
ground vehicle.
Use Mags ON The Use Mags setting enables turning on and off the magnetometer feedback for
yaw/heading stabilization. The default setting is ON.. When Use Mags is turned
ON, the unit uses the magnetic field sensor readings to stabilize the drift in yaw,
slaves the and it yaw to the compass reading provided from the magnetic field
sensor readings.
When Use Mags is turned OFF, the heading (yaw) angle measurement of the unit
will be slaved to the GPS heading if GPS is available, otherwise the heading will
ff the
.
drift feely. The reason for this setting is to give the user an ability to turn o
magnetometer stabilization when severe magnetic distortion may be occurring
This setting is desirable when the user vehicle temporarily moves in close
proximity to a large ferrous object. When the Use Mags switch is turned from
OFF to ON, the unit will reinitialize the yaw/heading angle with the compass
reading provided from the magnetic field sensor readings.