GPS World, February 2014

Policy and system news and developments GPS Galileo GLONASS Compass SYSTEM THE Competition for the Gold Standard BeiDou Releases Public Service Performance Document In late December director Ran Chengqi of Chinas Satellite Navigation System Management Office announced the BeiDou Navigation Satellite System BDS Public Service Performance Standard The document details the public service performance parameters of the BeiDou system including service area accuracy integrity continuity and availability It is a basic commitment to customers from BDS providers but also an important basis for customers to choose use and evaluate the system performance Also released is Version 2 of the BDS Interface Control Document ICD for the Open Service Signal Among other changes it includes a description of the B2I signal on 1207140 MHz The publishing of the Public Service Performance Standard a common practice among GNSS operators is also a prerequisite for BeiDou system involvement in international civil aviation international maritime 3rd Generation Mobile phone System and other international standardsetting organization activities The document has Chinese and English versions Because document download from the BDS government website can be difficult Richard Langley has made them available at the University of New Brunswick website http www2 unb ca gge Resources beidou_ open_ service_ performance_ standard_ ver10 pdf http www2 unb ca gge Resources beidou_ icd_ english_ ver20 pdf Analysis John Lavrakas of Advanced Research Corporation posted the Standard GPS BeiDou URE accuracy 6m 95 ZAOD 78m 95 all AODs URRE accuracy 0006m s 95 0006m s 95 URAE accuracy 0002mm s 95 0002mm s 95 UTCOE 40ns 95 2ns 95 Continuity 09998 h 0994 h Unscheduled Advance Notice NANU 48 hr n a Unscheduled Notice As soon as possible after Baseline Slot Availability PDOP 6 98 global 88 worst site Horizontal Availability 17m 99 global 90 worst site Vertical Availability 37m 99 global 90 worst site Horizontal Accuracy 95 9m 10m Vertical Accuracy 95 15m 10m Time Transfer 95 40ns 50ns TABLE 1 Coded to show green for the GNSS service committing to a more stringent standard over the other Courtesy of Advanced Research Corporation following comment to the online version of this news story I took a quick look at comparing the BeiDou Open Service Performance Standard with the GPS Standard Positioning Service Performance Standard and obtained mixed results In some cases the commitments from BeiDou were stronger URE accuracy the table to show green for the GNSS service committing to a more stringent standard over the 25m ZAOD 95 event n a 0957 n a 98 global 95 global 95 global other vertical position and in other cases the commitments from GPS were stronger continuity of service advance notice of outages The good news is that GNSS systems are documenting the service levels that users can expect What we will need next is monitoring to verify these service levels are being met Here is a link to my quick look http oregonarc com 2014 01 beidouperformance standard how good is it GPS World February 2014 www gpsworld com 8