4

GPS Orion PRODUCT BRIEF

NOTES:

1) COLD START:-

A cold start results when there is no valid Almanac or Ephemeris information available for the satellite

constellation in SRAM, or when the time and/or position information is NOT known (i.e starts at 0 in both

cases).

Also a cold start will be initiated if an Almanac is valid, but a fix cannot be achieved within 10 minutes of

power-up. This could occur if the receiver position has moved significantly since it was last powered-up, but

the position change and time are NOT initialised by the user

2) WARM START:- A warm start results when there is a valid Almanac, and the initial time and position are known in SRAM,

but the ephemeris is NOT valid (i.e more than 4 - 6 hours old).

3) HOT START:-

A hot start results when there is a valid Almanac, valid ephemeris (i.e. less than 4 - 6 hours old), and when

accurate time and position information are also known in SRAM (position error less than 100km, time error

less than 5 minutes). This can be simulated by a momentary Soft-Reset (i.e. press the push-button on the

GPS Orion interface Board).

Next step

The GPS Architect is available for designers who wish to develop the software further. This software, which supports the GP2000

chipset is available in both executable and source format, and is available for modification and/or embedding into the target

application. Purchase of a GPS Architect Development System provides optimum flexibility and control in the design approach

demonstrated by the GPS Orion, and includes a licence to modify the software and use it in embedded form with the target

application.