I'm no expert, David, but it would seem that if the problem is progressive as you move north, then there might be an issue with projection. Does the projection of your BNG system match that of the one the GPS system in the vehicle is using?
Eric -----Original Message----- From: Eagle, David A [mailto:[EMAIL PROTECTED] Sent: Tuesday, October 28, 2003 5:29 AM To: [EMAIL PROTECTED] Subject: MI-L Off topic GPS Question - Scotland This is a vague question because I have very vague information at the moment and its posed at those of you who deal with GPS surveying...The surveys I am questioning are in Scotland, Uk. Situation: A vehicle survey with GPS tracking its position has been done in the Central Belt of Scotland (Glasgow, Edinburgh region) and the returned results when converted from Lat/Long to BNG were spot on. A similar survey further north near Dundee produced converted BNG coords with a southerly 10-15m error. Then moving further north still to a point near Aberdeen the coords are out to the south by 15-20m. The errors are consistent and seem progressive as you move north. My question to the masses is, how would you explain this and what would you do about it? I don't expect miracles as I haven't provided much technical detail... I am inclined to believe some sort of calibration may have been done in the south and not altered for the two northerly surveys...is there any way of checking in the NMEA message string whether the data is being corrected differentially? Any thoughts greatly appreciated...sorry about the sketchy info, its being fed to me slowly. Best Regards, David This email and any attached files are confidential and copyright protected. If you are not the addressee, any dissemination of this communication is strictly prohibited. Unless otherwise expressly agreed in writing, nothing stated in this communication shall be legally binding. --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 8902 --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 8908
