I have the S6 and Note 4 Android phones. Both of which have awesome GPS with Barometers and there is an awesome app that sends this data over bluetooth. But, in my recent investigations, I have discovered that Apple prevents Android phones from connecting with iOS devices via bluetooth. They are concerned about Malware...
Even so, that doesn't prevent you from connecting your iPad to your Android phone via Wi-Fi. Turn your phone's Wi-Fi Hotspot on, and connect your iPad as if your Android phone it's just another router.