OrbPro2 a Cesium distribution

EphemerisPositionProperty

new Cesium.EphemerisPositionProperty(options)

A position property that interpolates on demand from a static Float64Array of ephemeris state vectors. Designed for OEM (Orbit Ephemeris Message) data where positions (and optionally velocities) are stored at discrete time steps. For uniform-step data, index lookup is O(1): `index = (time - startEpoch) / stepSize`. For non-uniform step, binary search with temporal coherence cache (O(1) amortized for sequential animation playback). Supports Hermite interpolation when velocity data is present (stateVectorSize >= 6) and linear interpolation for position-only data (stateVectorSize = 3). Implements the full PositionProperty interface so that `viewer.trackedEntity` works correctly.
Name Type Description
options object Options.
Name Type Default Description
data Float64Array The ephemeris data as a flat Float64Array. Layout: `[x0,y0,z0, (vx0,vy0,vz0,) x1,y1,z1, (vx1,vy1,vz1,) ...]`
startEpoch JulianDate The epoch of the first sample.
stepSize number Step size in seconds between samples. Set to 0 for non-uniform step (requires `times` parameter).
stateVectorSize number 3 optional Number of doubles per sample. 3 = position only (x,y,z). 6 = position + velocity (x,y,z,vx,vy,vz).
referenceFrame ReferenceFrame ReferenceFrame.INERTIAL optional Reference frame of the ephemeris data.
times Float64Array optional For non-uniform step: array of Julian day numbers for each sample. Required when stepSize === 0.

Members

Number of ephemeris samples.
Step size in seconds (0 = non-uniform).

Methods

Compares this property to the provided property.
Name Type Description
other PositionProperty optional The other property.
Returns:
True if the properties are equal.
Gets the position at the provided time in the FIXED frame.
Name Type Description
time JulianDate The time.
result Cartesian3 optional The object to store the value.
Returns:
The position, or undefined if out of range.

getValueInReferenceFrame(time, referenceFrame, result)Cartesian3|undefined

Gets the position at the provided time in the provided reference frame.
Name Type Description
time JulianDate The time.
referenceFrame ReferenceFrame The desired reference frame.
result Cartesian3 optional The object to store the value.
Returns:
The position, or undefined if out of range.
Need help? The fastest way to get answers is from the community and team on the Cesium Forum.