Got the same gps issues using runtastic and Navigon or GMaps.
Found 8-10 satellites, but my position is jumping around.
Hope it is not a Hardwareissue like on transformer prime with tegra3.
HTC HD2 - WP7-Mango 7720
HTC One IC 3.2-5
HTC One-X - Stock
Acer Iconia Tab A700 rooted
Samsung ATIV S
Sony Xperia Go