I've read about determining the "state vector" on the Apollo missions, and I would imagine it's similar for voyager. The ping delay and Doppler shift should be

I've read about determining the "state vector" on the Apollo missions, and I would imagine it's similar for voyager. The ping delay and Doppler shift should be enough to determine 3D position and velocity with respect to some coordinate sysem. I know JPL ( and/or perhaps other agencies like ESA) have a computer model of the solar system where you can run a spacecraft's trajectory forward through time. It can also account for gravitational anomalies if the distance to a planet/moon is close enough where it matters. Assuming they have gravitational anomalies modeled for that body. I'm pretty sure at least Jupiter has a decent anomaly map. In voyagers case, using the sun as a point mass, combined with its state vector at any known time, any undergrad student who knows the vis viva equation can determine voyager's position at any time.