Specifically the position was originally deliberately
noisy thus reducing its effective precision in the short term†. This was called "Selective Availability" and the US military were supposed to buy military receivers which handled a different channel on which noise was not introduced, thus giving them an advantage over an enemy lacking this feature - but this misunderstands economy of scale. So faced with a situation where your army is much more technically sophisticated and would benefit from GPS precision, but the GPS receivers everybody has in stock are for civilians and so suffer from the noise, the correct US decision was "Turn off Selective Availability" and it has been switched off ever since. Newer GPS birds lack this pointless feature entirely.
†Because it's "just" noisy you can wait, and average out the noise. If you stand in one place patiently recording your apparent position, for long enough, the average is much more accurate. Or, one station which knows exactly where it is uses short range radio to tell moving stations what the error currently is in the signal, improving their accuracy. The latter is known as DGPS and still makes some sense without Selective Availability because the ionospheric conditions will be similar at a short range too, reducing error from those.
