A. Berarducci | Geology Reports

USGS2009

Absolute Measurement Session XIII IAGA Workshop Boulder Magnetic Observatory

The absolute measurement session of the XIII IAGA Workshop was held at the Boulder Magnetic Observatory June 10-13, 2008. Approximately 85 people attended this session. The main focus of the session was for observers to make and compare measurements using DIFlux magnetometers. The session also included absolute measurement training, with lectures and practical training. Also included were data processing training, an introduction to solar observations, and a discussion concerning timing for one-second data collection. Testing and demonstration of three instruments under development was also carried out during the absolute measurement session. The auto DI Flux was demonstrated by Jean Rasson. A triaxial DI Flux was demonstrated by Uli Auster and Anne Hemshorn. A fast delta Declination/delta Inclination (dIdD) magnetometer was tested by Laszlo Hegymegi. Results from the Auto DI Flux and triaxial DI Flux are included in the workshop results presented below.

Conference Paper↗

USGS2006

Airport geomagnetic surveys in the United States

The Federal Aviation Administration (FAA) and the United States military have requirements for design, location, and construction of compass calibration pads (compass roses), these having been developed through collaboration with US Geological Survey (USGS) personnel. These requirements are detailed in the FAA Advisory Circular AC 150/5300-13, Appendix 4, and in various military documents, such as Handbook 1021/1, but the major requirement is that the range of declination measured within 75 meters of the center of a compass rose be less than or equal to 30 minutes of arc. The USGS Geomagnetism Group has developed specific methods for conducting a magnetic survey so that existing compass roses can be judged in terms of the needed standards and also that new sites can be evaluated for their suitability as potentially new compass roses. First, a preliminary survey is performed with a total-field magnetometer, with differences over the site area of less than 75nT being sufficient to warrant additional, more detailed surveying. Next, a number of survey points are established over the compass rose area and nearby, where declination is to be measured with an instrument capable of measuring declination to within 1 minute of arc, such as a Gurley transit magnetometer, DI Flux theodolite magnetometer, or Wild T-0. The data are corrected for diurnal and irregular effects of the magnetic field and declination is determined for each survey point, as well as declination range and average of the entire compass rose site. Altogether, a typical survey takes about four days to complete. ?? 2006 Springer.

NATO Security through Science Series C: Environmen↗