The simple NEO tracking problem that we did for two observers in Sydney and Perth required simultaneous sightings on an object. Using the method of Least Squares we can combine a number of sightings taken at different times to get another estimate of linear 3D motion. The following example uses the same sightings as before but computes positions in the fixed celestial frame by rotating the geographic coordinates of the observers by the amount indicated by the GMST for the time of the sightings.
We get a fit that is very close to the results of the previous calculations. Note that the unit of time here is the day so V0 needs to be divided by 24 to get the speed in RE/hour.