NMEA Gps 4+‎

NMEA client and server.

Read GPS Data from core location ( or through direct connection for supported GPS, currently DUAL XGPS150 / 160 are supported ) and forward to other apps/devices through NMEA protocol ( supported by many apps ); an internal NMEA client automatically connects to NMEA Server if active ( or it can be used to test and display data from other NMEA sources, disabling internal server and configurating it )

NMEA Fps supports both TCP and UDP clients ( configurable ) . Note that UDP , for protocol limits, will work only when iPhone is connected to a wifi router

Current gps position cab be shown as qrcode, enlarged and shared

This app allows reading GPS info from devices that lack of an internal GPS ( such as iPod and iPad wifi ), and from your desktop pc, simply connecting to the device running NMEA Gps app; you can share the *same* gps info (possibly derived from an external GPS) among multiple devices ( even if they lack of an internal GPS); useful for regatta app , all members will get same info.

Follow this tutorial to connect QGIS to your iPhone GPS ( other GIS applications have similar features, please let me know if you successfully connect to other GIS applications, or directly comment the tutorial ):
http://www.3bsoft.com/it/menuprincipale/news/3-news/49-qgisnmeagps.html

Satellite data are not reliable when app connects to GPS through core location, that does not forward these kind of info; in any case, app can perform direct connection to DUAL XGPS 150 e XGPS 160 from dual electronics ( if available ), and get complete gps data (satellite info included) at a frequency up to 10 hz .
The dual gps is available here :
http://www.amazon.com/gp/product/B00E65TNYE/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=B00E65TNYE&linkCode=as2&tag=b3softcom-20&linkId=KL3ERE5LYWDFKS5H

You can activate LOG and export generated file to give a look to NMEA data and detect problems

Continued use of GPS running in background can dramatically decrease battery life.