Editing GLONASS (section)

===== Accuracy =====
At peak efficiency, the standard-precision signal offers horizontal positioning accuracy within 5–10 metres, vertical positioning within {{cvt|15|m}}, a velocity vector measuring within {{cvt|100|mm/s}}, and timing within 200 [[nanosecond]]s, all based on measurements from four first-generation satellites simultaneously;<ref name="miller_2000">"A Review of GLONASS" Miller, 2000</ref> newer satellites such as GLONASS-M improve on this.

GLONASS uses a coordinate [[Geodetic datum|datum]] named "[[PZ-90]]" (Earth Parameters 1990 – Parametry Zemli 1990), in which the precise location of the [[North Pole]] is given as an average of its position from 1990 to 1995. This is in contrast to the GPS's coordinate datum, [[World Geodetic System|WGS 84]], which uses the location of the North Pole in 1984. As of 17 September 2007, the PZ-90 datum has been updated to version PZ-90.02 which differ from WGS 84 by less than {{cvt|400|mm}} in any given direction. Since 31 December 2013, version PZ-90.11 is being broadcast, which is aligned to the [[International Terrestrial Reference System and Frame]] 2008 at epoch 2011.0 at the centimetre level, but ideally a conversion to ITRF2008 should be done.<ref name=icg8>[http://www.oosa.unvienna.org/pdf/icg/2013/icg-8/wgD/D3_3_2.pdf National Reference Systems of the Russian Federation used in GLONASS.] {{Webarchive|url=https://web.archive.org/web/20140714182933/http://www.oosa.unvienna.org/pdf/icg/2013/icg-8/wgD/D3_3_2.pdf |date=14 July 2014 }} V. Vdovin and M. Vinogradova (TSNIImash), 8th ICG meeting, Dubai, November 2013</ref><ref>{{cite web|url=http://www.glonass-iac.ru/en/content/news/?ELEMENT_ID=721|title=The transition to using the terrestrial geocentric coordinate system "Parametry Zemli 1990" (PZ-90.11) in operating the GLObal NAvigation Satellite System (GLONASS) has been implemented|website=glonass-iac.ru|access-date=2 September 2015|archive-date=7 September 2015|archive-url=https://web.archive.org/web/20150907014714/https://www.glonass-iac.ru/en/content/news/?ELEMENT_ID=721|url-status=dead}}</ref>