Retrieving and Sending GPS Data

The GPS returns the following data:

• Position, velocity, and time
• Accuracy of data
• Device status and settings
• Almanac data, such as data that describes the satellite orbit

You can retrieve this data by using the StartCall method to fill PNAPI structures at specified intervals. You then access the required data from these structures. This approach supplies instant data, but the data might be obsolete if not updated frequently.

    To get data from a PNAPI structure

1. Call StartCall to request that data be placed in PNAPI structures.

   This approach specifies which structures to update and how frequently to update them. You have the following update options:

   • Update structures once
   • Update structures at specified intervals
   • Update structures as rapidly as the GPS device can produce them
2. Call GetData to retrieve data as required.
3. Call StopCall to terminate updates.

    To send data to a GPS device

1. Use the SetData method to send data, such as time or position.
2. Use the SetData method to send configuration data to the registry.

   Do not alter almanac data; it contains GPS satellite location data.

    To format data using the conversion utilities

1. Retrieve data from a PNAPI structure.
2. Convert the data to the appropriate format.

   The following table shows the conversion methods that you can use to transform data between different formats.