GPS blackout

[smeaks]

I went down to the Sunderland Air show on Sunday. My GPS stopped as I neared Roker and mobile phone stopped. All sprang back into life when I went North again and got past Souter. Were the signals blocked by HMS Albion for the display craft? Or is my chartplotter just a bit crap? Or has Sunderland disapeared off the map?

 

[Evadne]

I would never be surprised to find gps stops working when near a warship of any nationality. Eeeither they leave their jammers on (designed to confuse gps-guided missiles, presumably) or they just radiate so much noise that our simple receivers get confused.

 

[KenMcCulloch]

[ QUOTE ]
I would never be surprised to find gps stops working when near a warship of any nationality. Eeeither they leave their jammers on (designed to confuse gps-guided missiles, presumably) or they just radiate so much noise that our simple receivers get confused.

[/ QUOTE ]
If that is true how does the warship's own GPS manage to see the satelites? I'm not saying you are wrong but there does seem to be a contradiction in what you say.

 

[Evadne]

I expect that if I knew the answer to that, and told you, I'd then have to kill you. /forums/images/graemlins/grin.gif Most likely their jamming signal isn't white noise and, knowing what it is, it's a piece of urine to filter it out.

 

[MarkJohnson12345]

The military use a different signal

Precise GPS (Land Surveying) use another two signals to get 1cm accuraccy.

And yer handhelds use yet another signal

Complicated aint it.

MJ

 

[Hoolie]

They also use upward-looking antennas shielded from their own noise and emissions

 

[Paulka]

Some call this "rocket science". Isn't it? /forums/images/graemlins/confused.gif

 

[KenMcCulloch]

[ QUOTE ]
They also use upward-looking antennas shielded from their own noise and emissions

[/ QUOTE ]
So how can the antennae 'see' satelites low towards the horizon then?

 

[Hoolie]

+/- 90 degree coverage from vertical

 

[radio1]

Hello

I was also anchored at the Sunderland airshow my Gps (Raymarine) was fine did not not noticw any blackouts and the alarm did not go off to tell me "no gps"

regards
franky