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Index of Subjects This is a multi-part message in MIME format. --Boundary_(ID_PEgs9RmnA5gzb/N7hkV0Xg) Content-type: text/plain; CHARSET=US-ASCII Content-transfer-encoding: 7BIT Hi All, Although I have no special knowledge regarding the spatial resolution of GPS receivers, I do have the perspective of a user. One of my applications is in the game called "geocaching". Cachers normally use small hand-held units (Garmin is the company which sells most of the small units used by cachers) which sell for $150 to $500. Units which sell for less than about $200 have a receiver which is less sensitive and so in deep cover may loose the signal. However they are not necessarily less accurate than the more expensive hand-helds. Estimated accuracy is at best +/- 5m. The more expensive units (my Garmin Map 60 Cx cost about $325 at MEC) find the satellite signals much faster, have a much more sensitive receiver (do not loose signal even inside the house) and MAY be more accurate - my unit indicates that the accuracy is +/- 3m, with medium to strong signals from 9 satellites. If the accuracy were only +/- 10 m, these units would be next to useless for caching. At the other end of the scale, I understand that surveyors and others who require better than 1m accuracy use back-pack type units with long antennas and they can achieve an accuracy of a few cm at best (I've seen +/- 10cm quoted). My feeling is that accuracy quoted of a few mm is impossible! Cheers, Bob McDonald Halifax bobathome@eastlink.ca --Boundary_(ID_PEgs9RmnA5gzb/N7hkV0Xg) Content-type: text/html; CHARSET=US-ASCII Content-transfer-encoding: 7BIT <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1"> <META content="MSHTML 6.00.6000.16788" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY style="WORD-WRAP: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space" bgColor=#ffffff> <DIV><FONT size=2>Hi All,</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>Although I have no special knowledge regarding the spatial resolution of GPS receivers, I do have the perspective of a user. One of my applications is in the game called "geocaching". Cachers normally use small hand-held units (Garmin is the company which sells most of the small units used by cachers) which sell for $150 to $500. Units which sell for less than about $200 have a receiver which is less sensitive and so in deep cover may loose the signal. However they are not necessarily less accurate than the more expensive hand-helds. Estimated accuracy is at best +/- 5m. The more expensive units (my Garmin Map 60 Cx cost about $325 at MEC) find the satellite signals much faster, have a much more sensitive receiver (do not loose signal even inside the house) and MAY be more accurate - my unit indicates that the accuracy is +/- 3m, with medium to strong signals from 9 satellites.</FONT></DIV> <DIV><FONT size=2>If the accuracy were only +/- 10 m, these units would be next to useless for caching.</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>At the other end of the scale, I understand that surveyors and others who require better than 1m accuracy use back-pack type units with long antennas and they can achieve an accuracy of a few cm at best (I've seen +/- 10cm quoted). My feeling is that accuracy quoted of a few mm is impossible!</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>Cheers,</FONT></DIV> <DIV><FONT size=2></FONT> </DIV> <DIV><FONT size=2>Bob McDonald</FONT></DIV> <DIV><FONT size=2>Halifax</FONT></DIV> <DIV><FONT size=2><A href="mailto:bobathome@eastlink.ca">bobathome@eastlink.ca</A></FONT></DIV></BODY></HTML> --Boundary_(ID_PEgs9RmnA5gzb/N7hkV0Xg)--
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