Hmm sounds like either a slow device, a built up area(full of buildings), slow internet the device is indoors.
I personally use WebView with the GPS and WebViewExtra libraries with an app that I developed for a small courier company that relies on GPS location tracking for signatures. Try the libraries that I mentioned previously and look for source code on the forum, there's plenty to work from.
The app works all the time every time and it picks up the location and updated the WebView extremely quickly. When the save button is taped, the data is stored on both the device and also in the cloud.
View attachment 57589
Enjoy...