Not just jamming. Spoofing and providing wrong locations to/of ships and, yes, bicycles...
Note that this is (at least as reported) only affecting the ubiquitous US civilian GPS signals which is what just about everyone uses.
There's also the encrypted US one used by the military, and then there's the European ("Galileo") system, the Russian, and also the Chinese options.
_____________________________________________________ Knowledge may be power, but communications is the key snipped-for-privacy@panix.com [to foil spammers, my address has been double rot-13 encoded]