This app allows you to take image and measure with low-cost GNSS module (like U-blox GNSS module or E-GNSS from potretudara : http://www.potretudara.com/low-cost-gps-gis/ ). Measured coordinates from low-cost GNSS module are stored to EXIF image metadata in time when you tap the "capture" button. Use this to create your geotagging more precise to sub-meter level. Very useful for census, GIS support, reporting issue, and others.

You can still use internal GNSS for geotagging by deactivate BASE and ROVER in the Input Stream menu. Obviously none of the precision algorithm found in RTKLIB can be use.