So aren't 4 ground stations enough then? Just how many ground stations do you need to get an accurate position? As I say, if you're going to promote a product on here, expect your sales-pitch to be challenged by those of us disappointed with it.
Well Tarbat, I have nothing to do with COAA and I am not making a sales pitch for PlanePlotter; I'm just a very satisfied user. If you read my posts properly you will see that I suggested that the OP look at the PlanePlotter site, I didn't tell him to buy it.
I'm not absolutely sure how many ground stations are required to give accurate fixes and tracks. Do you know if all three stations were operational at that time? I've just tracked three USAF C-17s for over 200 miles and all showed perfect tracks along their ATC routings apart from very slight deviations due to course corrections.
Of course a lot depends on how savvy the user is with multilateration. I'm very savvy and have set mine up on two PCs and three laptops in minutes.
I remember you had a bad attitude to the PP people right from the start because you were unable to set it up properly. Your posts are still on the user group forum. Perhaps you still have not got it right.
Why not pop over there and see the number of new users who are getting Master User and Ground Station authorization every day. It may not be perfect but it's getting better and it's getting better every day.