Motorola i88s manual Recommendation

Motorola Inc. i88s J2ME Developers’ Guide

1.4Recommendation

•GPS Driver requires about one second to calculate a new fix, so any request for a new fix during this one-second period may result in the exact same position information including the time stamp. Therefore it is recommended that an application request a new position no more than once per second.

•If an application needs continuous position it is recommended to use “delay=low” once and “delay=high” there after even if the first fix does not succeed. The reason for this is because of network failures. When there is a network failure, there is a 12 to 24 second communication timeout from the LES.

•Use “delay=no” if the application only needs the cell latitude and longitude.

•Applications must handle all response codes returned by the AggregatePosition getResponseCode() method and the PositionConnection getStatus() method. getStatus() provides the connection’s status after the fix and user interaction status with regards to permission. getResponseCode() provides information about the position itself.

•Applications must always check the speed uncertainty value before using speed and heading. Although it is counter-intuitive, the presence of speed uncertainty denotes that the speed and heading value are accurate. Therefore, if a call to hasSpeedUncertainty() returns true, the speed and heading returned by the API are valid.

•If an application calls getPosition(String name) method with the “fix=extended” tag, this method will return accurate velocity and heading direction; however, there is a time penalty since it takes longer to calculate the accurate velocity and heading direction when the method is called.

•The method, PositionConnetion.getStatus() provides the status of the connection when the method PositionConnection.getPosition() was called. Whereas, AggregatePosition.getResponseCode() returns the detailed response code.

•Getting a position for the first time after the phone powers on is referred as a “cold start”. A position retrieved within ten seconds of the previous fix is referred to as a “hot start”. A position retrieved after ten seconds of the previous fix is a “warm start”. After 1 hour since the last fix will set the device back to “cold start”. Therefore, “hot start” is the quickest way of retrieving a fix.

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