The use of Global Positioning Satellite (GPS) technology is now core to all earth science disciplines. Advances in the last 20 years with respect to GPS technology has made it easier and easier to accurately position data on a global basis.
GEM believes that the high quality results that our magnetometers provide should be accurately positioned and we offer a number of options for precise positioning. Benefits include the ability to see your data accurately positioned quickly following a survey for immediate follow-up and interpretation. This allows better and faster decision making.
Examples of typical applications include:
GEM offers a range of options to meet various customer needs. GEM addresses our customer requests for GPS and its higher resolution derivative, Differential GPS (DGPS) through both built-in and external GPS options. Built-in GPS offers many advantages because it minimizes weight and removes bulky components that can be damaged through normal survey procedures.
GEM Overhauser System with GPS
Multi Geophysics System with GPS (Mag, GRAD, VLF-EM)
Some customers, for example, want a very simple GPS solution that only provides time synchronization for very accurate base station work. Other customers require an advanced DGPS solution with centimeter positioning accuracy for highly detailed survey results.
All options, with the exception of the base station option, give you access to a unique Navigation package which includes:
For More information on GPS in General.. See below.
GEM systems uses built-in GPS boards that are carefully selected for performance and non-magnetic properties.
GPS basics – understanding positioning accuracy and navigation-a cross-section of terms and alternatives
Accuracy of GNSS (GPS,Glonass, Galileo, Beidou etc.) data at the time of collection can vary significantly due to several reasons, including but not limited to the following.
Typically accuracy is in the range of 1 to 10 metres depending on what type of receiver is used. Basic GPS service with GEM provides accuracy in the 1.5 – 2 m accuracy.
For those who want to learn more about general GPS principles, you may want to refer to www.Novatel.com – Introduction to GNSS positioning. This resource provides a good overview from one of the premier hardware manufacturers.
The next best level of accuracy that users can achieve is with DGPS (differential GPS). This is usually obtained by applying corrections, , utilizing a GPS base station. (much like a magnetic base station). This can be cumbersome to do on a regular basis, so the international community decided to provide base stations and corrections for public use. This is accomplished automatically through an additional network of satellites and is provided free in certain regions of the world. This service is called SBAS. SBAS incorporates 4 regionally provided services which cover areas in North America, Europe, India and parts of Asia. SBAS provides “corrected” readings for GNSS data. When operating in SBAS regions accuracy is improved to 70 cm for GEM’s standard GPS solution.