I sell offline mapping iPhone apps. The GPS chip in the iPhone sometimes works (in open fields, clear view of the sky) without assistance, but often does not wh

I sell offline mapping iPhone apps. The GPS chip in the iPhone sometimes works (in open fields, clear view of the sky) without assistance, but often does not where standalone units would. This may be a software problem. Core Location has a tendency to give up pretty easily, whereas a standalone unit would keep trying as long as you wanted it to.