I suppose that it's conceivable that every carrier, the FCC, NENA and APCO are all stupid.
On the other hand, the carriers spend millions of dollars testing every year. So, perhaps they aren't quite so stupid. I don't have access to the full paper to understand what a "20 minute field test" is, but the largest problem for 100 meter 95% confidence is the fact that the GPS is not always enabled (for battery drain reasons) and unless it's on and seeing satellites for many minutes, you don't get really good accuracy. Also, field tests are usually conducted in open sky situations, and not urban canyons, or even tree leaf cover situations, which degrade performance considerably. Brian On 3/9/10 8:33 PM, "Henning Schulzrinne" <[email protected]> wrote: > As they say, [citation needed]. > > See > > http://www.doylesdartden.com/gis/gpstest.htm > http://gisandscience.com/2009/07/15/accuracy-of-iphone-locations-a-comparison- > of-assisted-gps-wifi-and-cellular-positioning/ > http://farmindustrynews.com/farm-equipment/precision-farming/farming_on_target> / > http://www.ehow.com/facts_5030374_accurate-gps-system.html > http://www.gpsworld.com/gnss-system/expert-advice-does-anybody-really-know-wha > t-accuracy-is-4190 > > for different perspectives. [The second one only mentions the median in the > abstract, so it's theoretically possible that you could have trouble with 95% > within 100m, but it seems unlikely.] > > Henning > > On Mar 9, 2010, at 5:52 PM, Brian Rosen wrote: > >> I will fix the nits as you suggest. >> >> We have quite a bit of experience in the U.S. with what kind of GPS accuracy >> we can get. There are millions of phones and tens of thousands of calls >> annually using GPS positioning. It is quite difficult to achieve a 100 >> meter accuracy 95% of the time. Technology is improving all the time, but >> at the moment, carriers are struggling to achieve the regulatory mandate for >> 100 meter uncertainty, 95% confidence. >> >> WGS84 is the most commonly used international datum. IETF emergency calling >> is based on IETF geopriv standards (see RFC4119), which specifies WGS-84. >> >> Brian >> >> >> On 3/8/10 10:44 AM, "Francis Dupont" <[email protected]> wrote: >> >>> I have been selected as the General Area Review Team (Gen-ART) >>> reviewer for this draft (for background on Gen-ART, please see >>> http://www.alvestrand.no/ietf/gen/art/gen-art-FAQ.html). >>> >>> Please resolve these comments along with any other Last Call comments >>> you may receive. >>> >>> Document: draft-ietf-ecrit-framework-10.txt >>> Reviewer: Francis Dupont >>> Review Date: 2010-03-05 >>> IETF LC End Date: 2010-03-10 >>> IESG Telechat date: unknown >>> >>> Summary: Almost Ready >>> >>> Major issues: None >>> >>> Minor issues: the Terminology is incomplete (no PSAP for instance) >>> and the GPS stuff seems a bit USA centric (IMHO you should show >>> the document to a GPS (or Galileo :-) expert). >>> >>> Nits/editorial comments: >>> - ToC page 2: Acknowledgements -> Acknowledgments >>> >>> - 1 page 3: add USA to National (if the NENA is a USA organization :-) >>> >>> - 1 page 3: I'd *really* like to get an entry for PSAP here! >>> >>> - 1 page 3: IMHO there should be an entry for LoST too. >>> >>> - 1 page 4: RoutinglLocation -> Routing Location >>> >>> - 2 page 5: e.g. -> e.g., >>> >>> - 2 page 5: expand EV-DO? >>> >>> - 3 page 10: AliceE -> Alice >>> >>> - 3 page 10: missing [M7] and [M8] >>> >>> - 3 page 10: floating "Figure 2" without a figure (from the .txt version) >>> >>> - 3 page 10 (in ESRP entry): sip -> SIP >>> >>> - 3 page 10: e.g. -> e.g., >>> >>> - 6 page 15: I don't know the quality of GPS in mobile phone, I have >>> a GPS receiver for pedestrian (surely best conditions: open-sky, >>> low speed), its accuracy is between 4 and 15 m (displayed) and >>> <10m at 95% (vendor specs in peace time) without WAAS (I use it >>> in France) so your numbers are a bit conservative. >>> >>> - 6.1 page 16: WGS 84 could (should :-) be replaced by another >>> system and as far as I know it is not the system used in Europe >>> (I don't know for ASIA). >>> >>> - 6.2 page 17: e.g. -> e.g., >>> >>> - 6.5 page 20: requestor -> requester? >>> >>> - 6.8 page 23: UAC -> UA (typo? if not the abbrev should be expanded) >>> >>> - 6.10 page 25: United States -> United States of America >>> (yes, there are more than one United States :-) >>> >>> - 7 page 26: IMHO you should add a reference for LoST >>> >>> - 8 page 27: AP -> access point >>> >>> - 9.1 page 28: xref problem (missing '<' in XML?) >>> >>> - 9.1 page 28: IPSEC -> IPsec >>> >>> - 10 page 30: please define AoR abbrev at its first use. >>> >>> - 12 page 30: i.e -> i.e., >>> >>> - 15 page 31: some missing text before "includes a description" >>> >>> - 18 page 32: Acknowledgements -> Acknowledgments >>> >>> - Authors' Addresses pages 36 and 37: US -> USA >>> >>> Regards >>> >>> [email protected] >>> >>> PS: you have some comments from Cullen Jennings too. >> >> >> > _______________________________________________ Gen-art mailing list [email protected] https://www.ietf.org/mailman/listinfo/gen-art
