GLOBAL POSITIONING SYSTEM (GPS)
GPS is a key element of digital geologic mapping. It provides the link between the laser mapping data and an absolute global coordinate system. Ultimately, the accuracy of this location limits the user's ability to correlate one set of field data to another. The various GPS methods have a wide range of accuracy. There is also a wide range of receivers, from $100 to $30,000 or from 100 meter to millimeter positioning. This technology is rapidly evolving. GPS is replacing most positioning and surveying applications. It can be done accurately, efficiently and cost effectively by non-surveyors and in many cases by a single person. If differential measurements are done in "real time" RTK (Real-Time Kinematic) for centimeter level or DGPS (Differential GPS) for decimeter to several meters level) then one person can navigate (or "stake out" ) and/or accurately position stations simultaneously. Geoscientists can take advantage of the developments; the equipment can be learned quickly, and better data than most conventional surveys can be generated by the careful novice user.
For the digital mapping, we have used RTK system, which is real-time kinematic GPS technique employing a method of carrier-phase differential GPS positioning which is the highest precision, centimeters in real time (For Utah Corbula Gulch mapping, Wyoming regional subtle structure mapping, and Dallas postal office outcrop mapping). kinematic survey with post-processing (Utah Muddy Creek mapping) and DGPS in Egypt.
At UTD we have two dual frequency Trimble 4000SSE receivers, and 2 Leica SR530 RTK systems ( 4 receivers) with Pacific Crest radios. We also have two Trimble Geoexplorer handheld GPS recievers, a Landstar MARK IV RACAL/Ashtech DGPS system, and a MBX Coast Guard Beacon for real time differential GPS corrections,
