Product specifications

Crescent Integrator’s Manual 24
C HAPTER 4: C RESCENT V ECTOR
O PERATION
This chapter introduces the general operational features of the Crescent Vector
system, operating modes, and receiver default operating parameters.
P OWERING THE C RESCENT V ECTOR S YSTEM
As described in Chapter 2: Introduction, the Crescent Vector is powered by a 3.3
VDC power source. Once appropriate power is connected, the Crescent Vector will
be immediately powered.
With the application of power, the Crescent Vector board will proceed through an
internal start-up sequence, however it will be ready to communicate immediately.
When installed such that the antenna you are using has an unobstructed view of the
sky, the Crescent Vector will provide a position quickly, within approximately 60
seconds. SBAS lock requires approximately 30 seconds to acquire.
Note: It can take up to 5 minutes for a full ionospheric map to be received
from SBAS. Optimum accuracy will be obtained once the Crescent Vector is
processing corrected positions using complete ionospheric information.
I NSTALLATION O VERVIEW
Due to the inclusion of the tilt sensor and gyro, the Crescent Vector OEM 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 Crescent Vector OEM board.
• 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 Crescent Vector OEM provides - either pitch
or roll). Heading is calculated from the Primary to Secondary antenna, so
standard installations usually have the Primary towards the stern and Secondary
to the bow of the vessel.
• 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 Crescent Vector 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 Crescent Vector does not support a command to translate its position to the
vessel centerline if the Antenna Array is not mounted on the centerline.