Jeff Hopper said:
This is one of those areas where the Referee usually decides whether or not a ship can be traced through jump.
Yep.
Just think about how tracing a ship through jump will affect your game universe and then make the decision of either yes or no. If it is allowed, then think up ways for ship captains to spoof the trace (short jumping, jumping at a different vector than your direction, etc).
There are all sorts of ramifications to jump tracing that can have some interesting, if mostly minor, impacts on the game universe. It doesn't matter if you say yes or no, but if you pick yes, be consistent in the effects. If the PCs can do it, so can a lot of other people.
The biggest ramification that comes to mind is that depending on how easy it is, systems may have routine monitoring systems in place that scan the are for departing/arriving ships, and record the data with a list of possible destination/origin points. This database would be used in things like skip tracing and criminal investigations, and even determining who gets customs inspections - IE, if a ship, upon arriving in system A, transmits info that it is arriving from system B, when in fact it came from system C, computer monitoring of jump arrival information may flag the ship as needing a customs inspection because of the discrepency.
If the data is a bit harder to sift through - like it usually takes hours of investigating the sensor data and computer time to derive the information, you'll probably find that there are specialists for this sort of work. Many systems will have specialists who can be hired (at significant cost, I'm sure) to provide this information where data is available, and Military ships will almost always try and have a specialist or two onboard specifically for this. In these cases, the data will be mostly used in a historical context - in order to provide intelligence data on routine enemy ship movement patterns, and build criminal cases against ship owners/operators, not trying to follow a ship that just fled system.
IMTU, calculating the jump vector is relatively easy for an Astrogator with average skill, its getting reliable data that's the hard part. I use the lanthanum grid model for the j-drive, so a good clear visual of the arriving or departing ship is basically all that's needed, and the ships last known vector helps as well. A good visual does require knowing where the ship you're tracking is, which means having your sensors pointed in the right place when the ship jumps. The further you are away from the target, the more things they can do to "fool" you - like change vector, add flashing decoy lights to obsfucate the grid flash, etc.
Higher tech and/or higher traffic systems routinely monitor incoming and outgoing ships with satellite and "bouy" netowrks, and log the data, but the data is rarely used in real time. A computer routine will scan the data as it's stored, and flag any gross discrepencies for further action, but for the most part, it isn't doing the analysis required to give a definitive answer.