On 9/27/21 13:34, Mark Lindsey via VoiceOps wrote:
In the top 25 cellular market areas, nationwide cell phone providers are already required to provide Z-axis (elevation) data within 3 meters for 80% of calls [for compatible devices]. ?The requirements increase each year; by 2026, /all/?cellular providers are required to provide z-axis precision for dispatchable location of +/- 3 meters everywhere in the US.
This is all in addition to providing +/- 50 meter horizontal (x, y axis, also known as latitude and longitude) precision for 911 calls.
Interesting as elevation accuracy for GPS is worse than lat/long. So when first responders get dispatched to 34.2270545 degrees north, 117.6422397 degrees west, 538 meters AMSL, where do they go? (I just randomly typed those numbers so if it's under a mountain don't blame me.) Considering just the x/y axis, determining the right room or suite in a large single-story office building, factory or warehouse is going to be a challenge. In a huge multi-story high-rise with poor to no internal GPS reception it's going to be nearly impossible. Especially if it's in the middle of a bunch of other high-rise buildings with corresponding multipath and reflections. -- Jay Hennigan - jay at west.net Network Engineering - CCIE #7880 503 897-8550 - WB6RDV