How to reduce iPhone battery consumption while using GPS

I am using GPS to actually monitor if I have entered a regions (radius 100 m).

I am using a hybrid of significantLocationChanges and hardware GPS, startUpdatingLocation.

As significantLocationChanges are not as accurate as I require I am using them only to check if I have entered a outer circle of X m. Then I use hardware GPS to check if the user enters an inner circle (100m).

The problem with it is that battery is getting开发者_如何学C drained pretty quickly, can anyone help me out.

I was concerned about the same issue and today i have made a simple test with MotionX on iPhone 4 , covering the distance of 15 km in 4 hours, with frequent audio coaching, taking photos, saving waypoints, checking the position on map and tracking the route. After 4 hours i had still 50% of battery power. Which shows that it would probably covered 8 hours route. Good enough, or?

So there must be some ways of wise GPS management, which MotionX knows (they say it proudly in their tech. description)

Here's a preview of a nice read (High Performance iOS Apps):

https://www.safaribooksonline.com/library/view/high-performance-ios/9781491910993/ch04.html

You'll see it covers battery usage in general, so search for "gps" for specifics. I use this as a reference so I don't forget any of it's tips. Enjoy the read :)