Specifications

WM_PRJ_Q2501_PTS_001 – 003
March 2004
© 2003 All rights reserved
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Term Definition
Hot Start Start mode of the GPS receiver when current
position, clock offset, approximate GPS time and
current ephemeris data are all available. In Hot
Start Scenario, the receiver was off for less than
2 hours. It uses its last Ephemeris data to calculate
a position fix.
Warm Start Start mode of a GPS receiver when current
position, clock offset and approximate GPS time are
known. Almanac data is retained, but the
ephemeris data is cleared. In Warm Start Scenario,
the receiver knows - due to a backup battery or by
other techniques – his last position,
approximate time and almanac. Thanks to this, it
can quickly acquire satellites and get a
position fix faster than in cold start mode.
Coarse Acquisition
Code (C/A Code)
The standard positioning signal the GPS satellite
transmits to the civilian user. It contains the
information the GPS receiver uses to fix its position
and time. Accurate to 24 meter. This code is a
sequence of 1023 pseudorandom binary biphase
modulations on the GPS carrier (L1) at a chipping
rate of 1.023 MHz, thus having a code repetition
period of 1 millisecond. The code was selected to
provide good acquisition properties. Also known as
the "civilian code.".