ISO INTERNATIONAL STANDARD 16695 First edition 2014-02-15 Space environment (natural and artificial) Geomagnetic reference models Environnement spatial (naturel et artificiel) - Modeles de réference du champ magnétique terrestre Reference number IS0 16695:2014(E) LSO IS02014 HS under ted without license from IHS Not for Resale IS0 16695:2014(E) COPYRIGHTPROTECTEDDOCUMENT ISO2014 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56:CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyright@iso.org Web www.iso.org Published in Switzerland @ IS0 2014 - All rights reserved No reproductic networking permited without license from IHS Not for Resale IS0 16695:2014(E) Contents Page Foreword ..iv Introduction. ..V 1 Scope. .1 2 Reference frames ..1 2.1 General 1 2.2 Geocentric reference frame .2 2.3 Geodeticreferenceframe 2 2.4 Geodetic to geocentric coordinate transform 3 Specification of the geomagnetic field vector. 3 3 3.1 General .3 3.2 Magnetic vector components in the geocentric frame ..4 3.3 Magnetic elements in the geodetic reference frame 4 3.4 Transform of magnetic vector components from geocentric to geodetic frame ..6 4 Specification of the geomagnetic reference model .6 4.1 Potential of the magnetic field .6 4.2 Geomagnetic reference radius ..8 4.3 Epoch of a sub-model .8 4.4 Validity of a sub-model .8 4.5 Time-dependence of Gauss coefficients ..8 4.6 Calculation of magnetic vector components in the geocentric reference frame .9 4.7 Spatial wavelength .10 4.8 Root-mean-square difference between two model fields .10 5 Examples of the use of geomagnetic reference models .11 5.1 Compute reference magnetic elements near the Earth's surface .11 5.2 Compute reference magnetic vector in near-Earth space ..11 5.3 Compute reference magnetic vector in magnetosphere ..12 Annex A (informative) Available geomagnetic reference models ..13 Bibliography ..18 iii se with ISt Not for Resale