The Electronic Trajectory Measurements Group (ETMG) addresses all aspects of operation, maintenance and performance for instrumentation radars, electronic warfare systems, continuous wave systems, Global Positioning System (GPS) based instrumentation systems, multilateration systems, and scoring systems utilized on DoD test and training ranges. The ETMG ensure that calibration methods and accuracy verification processes are created and updated to ensure the accuracies of these systems can be measured, documented, and certified. The ETMG promotes standardization in these systems including hardware, software, operation, and maintenance to the maximum extent possible. The group actively supports joint procurements of these systems and/or their respective calibration tools to the extent allowed in the RCC Operations and Policy Document. Ancillary equipment such as transponders, inertial systems, infrared sensors, television, lasers, masers, nuclear devices, and computer systems required to enhance the capabilities and accuracies of these electronic measurement and warfare systems also come under the purview of this group. In addition, the ETMG responds to theoretical and applied problems of propagation involving the entire electromagnetic radiation spectrum, including the technical interchange of information relating to the enhancement of instrumentation performance and accuracy, and data utility by range user analysts. The ETMG is composed of three standing committees: the Radar Committee, the GPS Committee, and the Range Instrumentation Accuracy Committee, with ad hoc committees as required to accomplish tasks.