No other Archers Fans,

GPS?

If so then he probably didn’t rate it because the early GPS ones were carp. In particular early, non-military, GPS systems were limited to a positional accuracy of +/- 100m so pretty hopeless for most “sat nav” type functions.

I was only dimly aware that there were satellite based systems before GPS - ground based systems being more common. Peter, you don’t recall the name of the system do you?