Model Orientation - ECI vs. ICRF

Hey Cesium,

We have an ongoing issue regarding orientation. We believe we’ve fixed most of our problems but still can’t seem to get orientation correct for all our validation checks.

We validate orientation based on how our model is represented at certain positions with certain quaternions during the vernal equinox (March 20, 2021 and September 20, 2021). We know that at these points it should be orientated a certain way.

That being said, we’re able to validate orientation for one of the vernal equinox but not both.

We believe it may be something with how Cesium interprets ECI frame but we’re not sure. Looking through support I see ICRF and see that ICRF is supposed to be the equivalent to ECI. My question is ICRF actually the equivalent of ECI, if not how does it differ. Can I represent my model in ECI in Cesium.

Any response is greatly appreciated.