Re:Super-Accurate GPS Chips Coming to Smartphones in 2018
by 24gttghh on Friday September 22, 2017 @01:14PM
(#15313980)
Leave it to stackexchange to shed some more light on the matter[0].
The original limits appear to be for units available for export, but I would guess manufacturers didn't want to deal with the headache of producing different models for import/export and just slapped the restriction down on everything. The poster does claim the original restriction was indeed an OR[1].
And current restrictions may only be 600 m/s? [2]pg 58
"Immediate access to satellite measurements and navigation results is
disabled when the receiver’s velocity is computed to be greater than
1000 knots, or its altitude is computed to be above 18,000 meters. The
receiver continuously resets until the COCOM situation is cleared."
The original limits appear to be for units available for export, but I would guess manufacturers didn't want to deal with the headache of producing different models for import/export and just slapped the restriction down on everything. The poster does claim the original restriction was indeed an OR[1].
And current restrictions may only be 600 m/s? [2]pg 58
[0]https://space.stackexchange.com/questions/14687/current-situ...
[1]https://www.ngs.noaa.gov/corbin/class_description/5700-5800V...
"Immediate access to satellite measurements and navigation results is disabled when the receiver’s velocity is computed to be greater than 1000 knots, or its altitude is computed to be above 18,000 meters. The receiver continuously resets until the COCOM situation is cleared."
[2]http://mtcr.info/wordpress/wp-content/uploads/2017/07/MTCR-T...