Vector Sensor Reference Manual 20
the outage lasts longer than 60 seconds, the gyro will be deemed to have drifted too far and the
Vector Sensor will begin outputting a heading based upon the magnetic sensor. There is no user
control over the time-out period of the gyro.
If the gyro is turned off and the magnetic sensor is the only secondary heading source, it will
provide a heading indefinitely until a GPS heading has been reacquired.
1.5 Installation Overview
Due to the inclusion of the tilt sensor, gyro, and magnetic sensor, the Vector Sensor system is
more complicated to configure than many traditional pieces of GPS equipment. The following list
summarizes the primary installation steps and points for consideration to successfully install and
configure the Vector Sensor system.
• Determine how you wish to install the Antenna Array (either along the boat’s axis or perpendicular to it
- this depends on whether or not you would like to use the second dimension of attitude that the Vector
Sensor provides - either pitch or roll)
• Choose an Antenna Array location with no structures above its horizon - failure to do so can reduce
heading accuracy, startup times, signal reacquisition times, positioning accuracy, and availability of
satellite signals from both GPS and SBAS. Make sure the Antenna Array is mounted away from other
electronics and antennas (especially active TV antennas) by at least a few feet, preferably more. Keep in
mind that the position computed by the Vector Sensor is referenced to the phase center of the primary
GPS antenna.
• You may want to install the Antenna Array on the vessel’s axis so the resulting position from the
primary GPS receiver agrees with the centerline of the vessel. The Vector Sensor does not support a
command translate its position to the vessel centerline if the Antenna Array is not mounted on the
centerline.
• Install the Antenna Array in a horizon (as best as can be accomplished - this will provide a foundation
for performance success when the internal tilt sensor is used to supplement Vector Sensor operation).
• You may choose to increase the antenna separation of the Vector Sensor to increase the level of heading
accuracy. Increasing the separation beyond the default 0.5 m requires the use of all internal sensors (tilt
sensor, magnetometer, and gyro). Because of the tradeoff between reliability and accuracy, we
recommend no more than a one-meter antenna separation. We have tested the Vector Sensor with a
2.0 m separation, which has yielded a 0.1° heading accuracy 95%. Use of the Vector Sensor with larger
than a 2.0 m separation is at your risk.
• Find a quiet location on the vessel from a radio frequency perspective to mount the MBL-3 antenna.
This should location should ideally have an omni directional view of the horizon and be mounted
reasonably high (keeping in mind serviceability).
• Install the Vector Sensor such that it is horizontal. The Vector Sensor front panel should point in the
opposite direction as the Antenna Array and be aligned to the Antenna Array to within a couple
degrees if possible. For example, if the Antenna Array points to the bow of the vessel (a normal
configuration), the Vector Sensor will face the stern of the vessel so that the front panel is visible to the
crew. This is a requirement if any or a combination of the tilt sensor, magnetic sensor, and gyro are
used.
• Connect the cables as required (power, data, and antenna cables)
• Compensate for any heading offset of the Antenna Array and Vector Sensor, in the Vector Sensor
configuration (the default is no compensation)
• Configure the NMEA data message output from the Vector (by default, Port A and B output GGA, VTG,
GSV, ZDA, HDT, and ROT at 1 Hz)
• Configure the baud rates if necessary (default is 19,200 for Port A and B)
To Next Page
Loading...
Need help?
General
