RNS510 GPS not working any more

Hi,
I have a problem for 2 months now.
The RNS 510 Navi isnt able to locate my GPS any more.

It always shows my position anywhere and also moves, but has no GPS fix and stable connection to satellites.
I also have a picture to show you..


The question is how to repair it .. I heard of flashing new firmware or what.. but I haven't ever done that
the only thing was to install new maps by dvd.. but that was years ago.

I also do not know much about the rns 510.. so version number or so..

I only can say that the car is a VW Touran (Cross Touran) and was built 2008. Maybe someone knows more about it.
Maybe an explanation how to install new firmware / maps or the link to the source will be great

thank you and I hope the problem will be fixed because it is really bad to have navi in car but not working :x

It's not necessary the map version you are using but the GPS antenna ...Sometimes they will rust at the base connection and as such cannot earth properly and then will not connect to satellites ...It's a common fault with the Ford Kuga an the symptoms are exactly the same...but not a cheap fix as the headliner has to be dropped to access the antenna ..Parts are reasonable from e-bay but its the fitting unless you confident

I just bought a new antenna with cable from e-bay (20-30EUR) from a polish dealer and fitted it under the dashboard. Works fine for more than 2 years now.