[tialaramex]

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.

[marsokod]

The parent poster is not talking about that, he/she is talking about the COCOM limits placed on GPS receivers sold commercially: the GPS would not provide an output when traveling faster than 1900km/h at an altitude over 18km (though some manufacturers used a logical OR instead of an AND). This limits still applies and you need to get a special license if you want to get these limits removed (or you can buy Chinese).

[tialaramex]

The parent poster wrote:

>And the precision used to be regulated, not by expense, but to give the military the superior tool.

Which was, as I said, referring to Selective Availability, and has nothing to do with the arbitrary limits which are still imposed on US made receivers.