ReferenceFrame Definitions


I have a simple question. What is the definition of INERTIAL when specifying the reference frame? I have looked through the documenation and the forum and have not been able to find the answer. My results have yielded that it is either ICRF or TEME but I want to make sure that it is not J2000.


Hey Tim,

If you specify INERTIAL in CZML, you get ICRF. One subtlety is that the ICRF transformation requires some data, so Cesium will use a “pseudo-fixed <-> TEME” transformation instead of the full “Fixed <-> ICRF” transformation in the meantime while that data is being downloaded. If that is a problem for your application, you can use Cesium.Transforms.preloadIcrfFixed(timeInterval) to pre-load the necessary data for a given time interval. That function returns a promise that, when it resolves, indicates that full transformation will be available for any time in the given interval. For example:

var start = Cesium.JulianDate.fromIso8601(‘2013-01-01T00:00:00Z’);

var stop = Cesium.JulianDate.fromIso8601(‘2015-01-01T00:00:00Z’);

var interval = new Cesium.TimeInterval(start, stop);

var promise = Transforms.preloadIcrfFixed(interval);

Cesium.when(promise, function() {

// when this function is called, the full ICRF transformation is available.

}, function() {

// if this function is called, something went wrong.