LinksPoint GPS Toolkit Reference
GpsInitializeReceiver
gpsapi.h | Generic GPS Functions | See Also
Initializes the GPS receiver
Parameters
Parameters Description
GPSINITMODE gimMode Specifies how to initialize the GPS receiver.
const PGPSINITTIME pgitTime Pointer to a GPSINITTIME structure when GPSINIT_WARM_START_WITH_DATA is specified, ignored otherwise.
PGPSPOSITION pgpPos Pointer to a GPSPOSITION structure when GPSINIT_WARM_START_WITH_DATA is specified, ignored otherwise.
Return Value
If the receiver has been successfully initialized, then the return value will be GPSERROR_NONE. Otherwise the return value will be GPSERROR_INVALID_PARAMETER.
Remarks
This function causes the GPS receiver to re-acquire a fix from one of several starting points, as specified by gimMode. These include cold, warm, or hot starts. It is not advisable to issue anything but a hot start in field applications.

 

  • A GPSINIT_COLD_START gimMode value will cause the receiver to discard all position and time information and search the sky for satellites. This is a lengthy operation, taking up to two minutes, and should be avoided. The only time it might be helpful is if the GPS receiver has been moved by more that 200 miles without navigating, invalidating the satellite list.

  • A GPSINIT_WARM_START gimMode value will cause the receiver to discard its ephemeris information, which takes at least 38 seconds to re-acquire. This can be helpful if particular satellites have become invalid since the last time the receiver navigated.

  • A GPSINIT_WARM_START_WITH_DATA gimMode value can improve the warm start time by supplying position and time in pgpPos and pgitTime. However, if this data is incorrect the start time will be vastly increased, so use caution to supply correct information for a warm start with data. The time data must represent Universal Time Coordinated (UTC) time and not local time. The position data should be supplied in units of decimal degrees.

  • A GPSINIT_HOT_START gimMode value will not discard any information, and can re-acquire a fix typically in less than 10 seconds. This type of start can be helpful in marginal GPS coverage conditions when the receiver fails to obtain a valid fix.

  • A GPSINIT_FACTORY_START gimMode value clears all GPS configuration, position, and time information and causes the receiver to perform a cold start.

  • The user is responsible for allocating and freeing the memory for the parameter(s).
See Also
Group
Declaration
GPSERROR GPSAPI GpsInitializeReceiver(GPSINITMODE gimMode, const PGPSINITTIME pgitTime, PGPSPOSITION pgpPos);
File
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