---------------------------------------------------------------------- Message-ID: <874kvcijed.fsf@bogus.nodomain.nowhere> Date: 27 Feb 2020 03:22:50 -0400 From: "Mike Spencer" <mds@bogus.nodomain.nowhere> Subject: Re: 911 operators couldn't trace the location HAncock4 <withheld@invalid.telecom-digest.org> writes: > One frustration is that some areas have consolidated their 911 call > centers, so they now serve a large geographic area. That means the > operator might not be familiar with a particular shopping center or > a residential street name that may be duplicated from one > development to another. Computers are supposed to keep this all > straight, but sometimes the programming or data isn't adequate or > the caller can't help. "I'm at the McDonald's on Rt 100" won't be > enough if there five McDonald's along the full length of Rt 100. My gravel road starts on a major highway, wanders 3 miles into the woods, then 2.5 miles back to a secondary paved road. The secondary paved road connects to the major highway a mile closer to "town" than the other end of my gravel road. I live half a mile from the secondary paved road and that half mile is the only part of my road that is well maintained. The only time in 50 years that I've had to call for an ambulance, the GPS directed them to the end of my road that connects to the major highway. So they had to thrash 5 miles over icy frozen ruts to reach me. They could have used the secondary paved road route for a total of 3 fewer miles, none of it over poorly maintained surface. So the location (911 via land line) worked perfectly but the routing was problematic. The fire department is local volunteer who would know the best route. Emergency medical is staffed from a wide area and dispatched from the local market town 13 miles away. Just an anecdotal data point, -- Mike Spencer Nova Scotia, Canada ------------------------------ Message-ID: <20200228012738.GA17225@telecom.csail.mit.edu> Date: Fri, 28 Feb 2020 01:27:38 +0000 From: Moderator <telecomdigestsubmissions@remove-this.telecom-digest.org> Subject: Fire at Escondido AT&T Building Impacts 911 Dispatch, Other Phone Calls By Karla Rendon-Alvarez Some Escondido residents and 911 dispatchers were unable to complete phone calls Thursday following an early morning fire at an AT&T building. Crews received a report of the blaze at about 3:45 a.m. on the 140 block of Broadway, according to the Escondido Police Department. There, smoke was seen coming from the second and third floors of the building. https://www.nbcsandiego.com/news/local/firefighters-battle-structure-fire-near-escondido-library/2273838/ -- Bill Horne Telecom Digest Moderator ------------------------------ Message-ID: <S0L5G.214333$tu4.13660@fx07.iad> Date: 27 Feb 2020 00:24:16 -0800 From: "Jay Hennigan" <jay@west.net> Subject: Re: 911 operators couldn't trace the location On 2/26/20 08:45, David wrote: > Often no. You need at least 3 satellites to get a Lat/Long fix. But > altitude is far harder to get close; more birds are needed to do so. > Open air easily gets you >>3 satellites. But inside a building is > harder. Plus you have the issue of how long it takes to get an initial > GPS fix. That can be up to 12 minutes. The other issue, particularly in urban areas, is multipath. As GPS depends on measuring time-in-flight, reflections from nearby buildings and within a building will severely reduce accuracy. You can see this in vehicles with GPS mapping systems. In urban areas with tall buildings it isn't uncommon to see errors of a city block or more. ------------------------------ ********************************************* End of telecom Digest Fri, 28 Feb 2020