createGroundStationLink Not working properly

[Kirito-oo1]

createGroundStationLink() {
if (!this.props.groundStationAvailable) {
return;
}
const polyline = new Cesium.PolylineGraphics({
followSurface: false,
material: new Cesium.PolylineGlowMaterialProperty({
glowPower: 0.5,
color: Cesium.Color.FORESTGREEN,
}),
positions: new Cesium.CallbackProperty((time) => {
const satPosition = this.props.position(time);
**const groundPosition = this.props.groundStationPosition.cartesian;**maybe is bug
const positions = [satPosition, groundPosition];
return positions;
}, false),
show: new Cesium.CallbackProperty((time) => this.props.passIntervals.contains(time), false),
width: 5,
});
this.createCesiumSatelliteEntity("Ground station link", "polyline", polyline);
}