Please follow me, Itís a little hard to explain.
The reason why the V1 arrows are only point forward, middle and rear is because it only has 2 radars. This is a copy and paste from ehow "The three circles you have created on the map should overlap at a single point. This is the epicenter (radar source) of the earthquake." It takes 3 seismic stations to find a pin point.
If we can take 3 radars on a single unit and link it with a gps, it will create a pin point on a map. For example; if the V1 unit has 3 rd's (not the 2 it has now) link it with the "RADAR ACTIVE" iPhone app with the GPS it should in theory pin point on a map the exact location of a radar source.