No GPS signal?

I have this portable PDA-Navisystem, which was sold 1 year ago in the Aldi. Especially often I don’t need it. Today was a day again. And what did the thing tell me: “No GPS signal” – and that over hours. Is such a message symptomatic for my device type (so far it had been mostly sporadic for a few minutes), or are the fixed installers sometimes affected by such messages? Even if the following question concerning the region itself I still put it: Did any of you still have this in the Ruhr region from 2 to 4 p.m.? I just have a point: Or is my GPS receiver in the bucket …?