Update an existing iPhone/IOS application to better support background operation of GPS

The existing application is an IOS GPS tracking app which accepts a configuration and then tracks the phone's location at a specified interval and sends the tracking data to a website for display. If internet connectivity is broken the phone continues to record GPS data on the phone and log to a file. The app constantly re-checks for an internet connection, and when one is found it will burst transmit the data to bring the GPS track on the website up to date and then continue updates going forward. This works. The problem is that when the app is in the background IOS eventually shuts down the app. Currently the "blue background GPS service" header does display, the phone does request background GPS operation for the app, and the app does do updates from the background for some period of time. Eventually, the app stops updating GPS data to the website, and additionally does not cache any data points once it 'hibernates'. Also, if the app is in the background the tracking timer does not cause the app to begin tracking as it should regardless of foreground or background status of the app. It's very important that the data be captured so long as the application is set to run and until the user tells it to 'stop'. It's also very important that the tracking begins when the timer indicates it will do so, regardless of whether it's in the foreground or background. I have the same application running on Android and it works perfectly without interruption of service. The IOS application is available (free) on the App Store as "Transponder" (Sailtracker Transponder).