RaceGrade M GPS BL V2 User Manual - page 4
RaceGrade
GPS
Page
3
Introduction
Thank you for purchasing a
RaceGrade
GPS receiver. This user’s
guide was written to help you understand how the
RaceGrade
GPS
(Global Positioning System) device works. Please read it thoroughly.
Installation is very important, and understanding how GPS works will
help you get the most from this sensor.
The GPS device uses an
antenna on top of the vehicle to
track satellites in orbit around
Earth. It takes a minimum of
three satellites to identify your
position on earth, and a fourth to
calculate accurate timing.
Satellites are constantly moving, and a satellite which the antenna sees
at the start of the race might not be visible minutes later. Satellites used
in the GPS solution are dynamically added or dropped based on signal
quality. Ideally you should have 8 or more satellites being tracked in
order to obtain good accuracy. Anything under 6 satellites is quite poor.
With more satellites, there is more information to correctly identify your
position with less error. So it’s easy to see the importance of your
antenna having a clear line of sight to the satellites in the sky.
The system is a 12 channel receiver, and able to use up to two of
the tracked satellites as special geostationary satellites (SBAS) which
provide DGPS (differential GPS) via WAAS correction. Therefore the
maximum reported satellites in the data will be 10. Differential GPS
uses those SBAS satellites to more accurately calculate your position.
Positional accuracy goes from 3 meters to under 0.7 meters with
Differential GPS.