Watson Industries, Inc.
GGC-E101 Rev A 08/30/2013
3
CAUTION!
Watson Sensors are rugged devices that have been used successfully in a number of harsh
environments. The components have been qualified to withstand a mechanical shock of 200g 's or
greater, and most enclosures provide an added level of protection. However, dropping a sensor
from waist height onto a hard floor can cause a shock level of 600g's. At this level, damage is
likely to occur.
Introduction
The GPS Gyro Compass System (GGC-E101) is a solid-state sensor system that provides the user
with dynamic measurements of Angular Attitude and Heading, together with GPS output messages.
This System consists of a DMS unit and two mounted GPS antennas inside a water-resistant carry
case.
Product Description
Watson Industries GGC-E101 uses solid-state gyros and silicon accelerometers. The solid state
vibrating structure angular rate gyros used in this system provide extremely high reliability, high
precision, low power consumption and shock resistance. There are no physical adjustments
required by the user since all of the primary transducers are locked into position during
manufacture.
The GGC-E101 incorporates a dual antenna Differential GPS (DGPS) system that allows the GGC
to output true North heading. This unit outputs Altitude, Latitude and Longitude based on the
position of the aft antenna.
This unit will operate in two heading modes. The unit operates in true North heading mode (“G”
label header on output message) when in dual antenna GPS is valid. In the event of loss of the GPS
signal, the unit switches to relative heading (“I” label header on output message) based on the last
accurate GPS heading. When GPS signal is restored, the unit reverts to true North heading when
dual antenna GPS is restored. The user may select to hold the unit in relative heading mode full
time. (See Appendix A Setting Velocity and Heading Modes)
Installation
Environment
Avoid mounting sites that are subject to significant temperature changes over the duration of the
test. Temperature variation could induce noticeable rate sensor bias drift, which could result in
degraded attitude accuracy.
This sensor system is housed in a water-resistant case. This case is air transportable and buoyant.
The GGC is a rugged device and will withstand harsh environments. However, due attention needs
to be paid to the nature of the sensor and its prime function, which is to measure attitude and
motion.
Calibration
The GGC is calibrated at the factory before it is shipped to the user. It is recommended that the
unit be returned to the factory annually for evaluation and recalibration.
