GPS satellites have been freely accessible to the world through the “public good” policy of the United States Air Force and their NAVSTAR Global Position System (GPS.) It is a system of satellites that broadcast a specific radio signal to be read by a receiver like this one. If three or more of the NAVSTAR satellites are in transmission range of the GPS unit, through simple mathematical calculations based on the distances between each orbiting satellite and the receiver, a 3-dimensional position on the X/Y/Z axes is determined. This in turn translates into latitude, longitude and altitude co-ordinates on a GPS receiver.

Geotagging has become an important part of digital photographic organization, classification and notation. The process involves obtaining coordinates from GPS transmissions, and embedding them in a way that allows a photographer to store the location to which the photograph was taken within the digital image file itself. In order to generate these coordinates, a GPS receiver like the Sony GPS-CS3KA GPS Image Tracker is required.

This multi-stage geotagger does not interface with a still or video camera, but rather operates alongside the camera, saving location data to a file that can be referenced later when the GPS-CS3KA tracker is linked to a Windows computer with an USB port. Sony’s included Picture Motion Browser software links the time stamp of the image with the time stamp of the GPS’s recording and then copies that data over to the image’s metadata or a sidecar file with video files.

The GPS-CS3KA GPS Image Tracker also features two memory card slots for geotagging on the fly. Simply remove the card from your camera after a shoot and insert it into the Image Tracker. The GPS receiver then scans the image files saved to an SD or Memory Stick Duo card and matches time and location without the use of a PC.