The Global Positioning System, usually
called GPS (the US military refers to it as NAVSTAR GPS -
Navigation Signal Timing and Ranging Global Positioning System),
is a satellite navigation system used for determining one's
precise location and providing a highly accurate time reference
almost anywhere on Earth or in Earth orbit. It uses an intermediate
circular orbit (ICO) satellite constellation of at least 24
satellites.
The GPS system was designed by and is controlled
by the United States Department of Defense and can be used
by anyone, free of charge. The GPS system is divided into
three segments: space, control, and user. The space segment
comprises the GPS satellite constellation. The control segment
comprises ground stations around the world that are responsible
for monitoring the flight paths of the GPS satellites, synchronizing
the satellites' onboard atomic clocks, and uploading data
for transmission by the satellites. The user segment consists
of GPS receivers used for both military and civilian applications.
A GPS receiver decodes time signal transmissions from multiple
satellites and calculates its position by trilateration.
The cost of maintaining the system is approximately
US$400 million per year, including the replacement of aging
satellites. The first of 24 satellites that form the current
GPS constellation (Block II) was placed into orbit on February
14, 1989. The 52nd GPS satellite since the beginning in 1978
was launched November 6, 2004 aboard a Delta II rocket.
In an ever more mobile world, modern GPS systems are available as in-car, handheld and on the wrist watch type systems all of which need a reliable sourch of power. Quite a number of these small devices take standard AA or AAA batteries and due to the nature of these systems they are best suited to rechargeable NiMh cells. Such GPS devices can require quite a high constant drain current as well as spells of pulse currents when large amounts of data are being processed.
Check out one of our news articles which goes into a little more detail about the cells we have available and lists of some popular GPS models.
Go to the news article. |
