NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Is this quite the thing or not?
From: Dan Allen
Date: 2002 Nov 5, 11:30 -0800
From: Dan Allen
Date: 2002 Nov 5, 11:30 -0800
Simrad has a new product with two GPS receivers in one instrument for added redundancy. Of course if the GPS system goes down this redundancy does nothing for you. Anyway, here is their simple description of the device: what does the group think of it? Are their claims justified? Does anyone know what it is doing -- the carrier phase data? In the spirit of having multiple ways of tracking your position (GPS, dead reckoning, celestial nav), it may be a big step backwards as it claims to replace a gyrocompass. It is this aspect that I am particularly interested in. --- From the Simrad website: --- The HS50 replaces several vessel instruments, such as a gyrocompass, GPS navigator and speed log in one compact navigation package. In addition the HS50 provides added position redundancy with two complete GPS receivers. Precision heading is derived from the fixed-distance dual GPS antenna arrangement in the Sensor Unit, using carrier phase data to generate heading information independent of latitude and vessel dynamics. GPS position and velocity are calculated from both of the two antennas, which gives total redundant position and velocity sources in this product. DGPS signals may be input to the HS50 to improve position and velocity accuracy. The inertial rate element provides yaw information. In case of short GPS outages, the inertial rate sensor automatically takes over as the prime source for heading determination until the GPS comes back on line. The rate element and GPS� are working together seamlessly to insure accurate, continuous and robust heading information even when the vessel is sitting still. --- See http://www.simrad.com/ for more details. Dan Allen