From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bosmailout02.eigbox.net (bosmailout02.eigbox.net [66.96.184.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 712A33CB37 for ; Mon, 13 Nov 2023 23:07:52 -0500 (EST) Received: from bosmailscan06.eigbox.net ([10.20.15.6]) by bosmailout02.eigbox.net with esmtp (Exim) id 1r2kiN-0006f5-UU for nnagain@lists.bufferbloat.net; Mon, 13 Nov 2023 23:07:51 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=alum.mit.edu; s=dkim; h=Sender:Content-Type:MIME-Version:Message-ID:Date: Subject:In-Reply-To:References:Cc:To:From:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=7qpZ914hBwbifXOg01pYH1i/KLCfMIOba1RNYYlNhkw=; b=lb3ziW+hYW/kD4yNstRQwW5tZr c6i7qVB1jyciZT3lI68jwuReuQAi9hcdRbBOkEh7m7jr8q9QdAqeH/AOagpqckaSOrHOYwB2p2uCh VpNSKCxBLrxlHxEeeGQpMnZg56UtBYRo7au462Fkl/XeZi8/5tYKH/ix4cSOChA/KBFk+XBPkH+PF yjEcQbcwYc0kJGfFZnVhtyenQURORJtenYO+nRUiODm2rte1vsjqTDLaoM9MUBjJNi56kenelbuEl WTuYTgabTOM24S5MBBKjlrCiCjEexXJXJ8GCdQ9PSE2YtLkh7jhyj/eqTgx30GiPO4vpTZqtBrHxb SX6IOscQ==; Received: from [10.115.3.32] (helo=bosimpout12) by bosmailscan06.eigbox.net with esmtp (Exim) id 1r2kiN-0000DW-Mq for nnagain@lists.bufferbloat.net; Mon, 13 Nov 2023 23:07:51 -0500 Received: from bosauthsmtp17.yourhostingaccount.com ([10.20.18.17]) by bosimpout12 with id A47o2B0020N5uqq0147rHz; Mon, 13 Nov 2023 23:07:51 -0500 X-Authority-Analysis: v=2.3 cv=dOg9ZNRb c=1 sm=1 tr=0 a=f4kFLigMKr8AH7rIJ//qJA==:117 a=tKttg/DTfI8zZz0UFxdR5w==:17 a=BNY50KLci1gA:10 a=r77TgQKjGQsHNAKrUKIA:9 a=kurRqvosAAAA:8 a=fUU-c8v4vFs9oXr8LO4A:9 a=wPNLvfGTeEIA:10 a=SSmOFEACAAAA:8 a=6q3_X2ChZdJWKllI6VUA:9 a=DDicV7GNfMmh8PP6:21 a=gKO2Hq4RSVkA:10 a=UiCQ7L4-1S4A:10 a=hTZeC7Yk6K0A:10 a=frz4AuCg-hUA:10 a=kbxRQ_lfPIoQnHsAj2-A:22 Received: from c-73-158-253-41.hsd1.ca.comcast.net ([73.158.253.41]:58486 helo=SRA6) by bosauthsmtp17.eigbox.net with esmtpa (Exim) id 1r2kiK-0003Ko-5N; Mon, 13 Nov 2023 23:07:48 -0500 Reply-To: From: "Dick Roy" To: "'dan'" , "'Dave Taht'" Cc: =?iso-8859-1?Q?'Network_Neutrality_is_back!_Let=B4s_make_the_technical_as?= =?iso-8859-1?Q?pects_heard_this_time!'?= References: In-Reply-To: Date: Mon, 13 Nov 2023 20:07:44 -0800 Organization: SRA Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0882_01DA166D.13206F30" X-Mailer: Microsoft Office Outlook 11 Thread-Index: AdoWjDTscNxjLaFcTi62yC5pdsAPlQAImEuA x-mimeole: Produced By Microsoft MimeOLE X-EN-UserInfo: f809475445fb8041985048e338e1a001:931c98230c6409dcc37fa7e93b490c27 X-EN-AuthUser: dickroy@intellicommunications.com Sender: "Dick Roy" X-EN-OrigIP: 73.158.253.41 X-EN-OrigHost: c-73-158-253-41.hsd1.ca.comcast.net Subject: Re: [NNagain] [Starlink] bluetooth occupancy sensing X-BeenThere: nnagain@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: =?utf-8?q?Network_Neutrality_is_back!_Let=C2=B4s_make_the_technical_aspects_heard_this_time!?= List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 14 Nov 2023 04:07:52 -0000 This is a multi-part message in MIME format. ------=_NextPart_000_0882_01DA166D.13206F30 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable =20 =20 _____ =20 From: Starlink [mailto:starlink-bounces@lists.bufferbloat.net] On Behalf = Of dan via Starlink Sent: Monday, November 13, 2023 3:50 PM To: Dave Taht Cc: Dave Taht via Starlink; Network Neutrality is back! Let=B4s make the technical aspects heard this time! Subject: Re: [Starlink] bluetooth occupancy sensing =20 I also have bluetooth occupancy sensors lol. We have a lab test going = of triangulated bluetooth tag locating. So you put a BLE tag on a device = and *3* or more receivers in a space at different locations and heights = which are documented and then BLE tags are triangulated based on RSSI. =20 [RR] This only works if ALL the sensors are synchronized. Adding more sensors does not help either, because for every sensor you add that=92s = not synchronized, you need to estimate a time bias/offset. And if the oscillators are not synchronized (in frequency), then you have another parameter to estimate =85 the frequency offset. It can get out of hand = really fast! The way this is =93normally=94 done is to =93calibrate=94 the area = around the sensors. What that really means is that =93array manifold vectors=94 = are collected during a calibration phase then used during the measurement = phase to =93locate the transmitters=94 and even that is a =93tricky = problem=94. Check out MUSIC!!! It=92s a half-century old! =20 Having sensors at various heights allows for tracking even the 'z' axis. These tags are very cheap, you can buy complete tags for a couple of = bucks, don't even have to build your own, and you can get them built into = cutable (or non-cuttable) wristbands. You can also do short-term tracking of = cell phone beacons, though privacy mode means that you only get a short = 'session' with a phone (because of privacy mode on newer phones) that isn't paired with something but if you have a phone with a bluetooth headset, the = 'locks' the bluetooth mac address and now you can track the phone anywhere that = the bluetooth headsets follow. You can also track cars which don't scramble = the mac, but you get cars with wifi mac as well. We can get bluetooth to within inches accurate when it's line of site.=20 [RR] This requires sub-nanosecond synchronization =85 remember it=92s a nanosecond/foot (the inverse of the speed of light that is!) :-):-) In a pocket or something it's about a meter because bodies/clothes etc reduce RSSI unevenly. The purpose of this is a couple of things, = 'patient tracking' in any sort of a facility like nursing home or hospital, and device tracking, again in a facility with shared hardware like portable = EKGs and handheld XRays etc that get 'misplaced' and staff has to go on a = hunt for. It's also much cheaper than lorawan as BLE transmits many times a second and runs for years while lora is built for more range and only transmits intermittently, usually 10-60 minutes to preserve battery. We're testing mainly on dragino and milesight devices. I'm also having decent enough luck with mikrotik's knot which can track BLE beacons with high enough precision. Mikrotik has their own somewhat expensive BLE beacons also but these are basically universal. [RR] If you are getting inch accuracy without addressing the = synchronization problem, I=92d love to hear how, especially when there are let=92s say = 10 BT transmitters to =93locate simultaneously=94. :-):-):-) ------=_NextPart_000_0882_01DA166D.13206F30 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

 

 

From: = Starlink [mailto:starlink-bounces@lists.bufferbloat.net] On Behalf Of dan via Starlink
Sent: Monday, November = 13, 2023 3:50 PM
To: Dave Taht
Cc: Dave Taht via = Starlink; Network Neutrality is back! Let=B4s make the technical aspects heard = this time!
Subject: Re: [Starlink] = bluetooth occupancy sensing

 

I also have bluetooth occupancy sensors lol.  We have a lab = test going of triangulated bluetooth tag locating.  So you put a BLE tag = on a device and *3* or more receivers in a space at different locations and = heights which are documented and then BLE tags are triangulated based on = RSSI. 

[RR] This only works if ALL the sensors are = synchronized. Adding more sensors does not help either, because for every sensor you add = that’s not synchronized, you need to estimate a time bias/offset. =A0And if the = oscillators are not synchronized (in frequency), then you have another parameter to estimate … the frequency offset. =A0It can get out of hand really = fast! The way this is “normally” done is to “calibrate” = the area around the sensors. =A0What that really means is that “array = manifold vectors” are collected during a calibration phase then used during = the measurement phase to “locate the transmitters” and even that = is a “tricky problem”. =A0Check out MUSIC!!! It’s a half-century old! = =A0

Having sensors at various heights allows for tracking even the = 'z' axis.  These tags are very cheap, you can buy complete tags for a = couple of bucks, don't even have to build your own, and you can get them built = into cutable (or non-cuttable) wristbands.  You can also do = short-term tracking of cell phone beacons, though privacy mode means that you only = get a short 'session' with a phone (because of privacy mode on newer phones) = that isn't paired with something but if you have a phone with a bluetooth = headset, the 'locks' the bluetooth mac address and now you can track the phone = anywhere that the bluetooth headsets follow.  You can also track cars which = don't scramble the mac, but you get cars with wifi mac as well.

We can get bluetooth to within inches accurate when it's line of = site. 

[RR] This=A0 requires sub-nanosecond synchronization = … remember it’s a nanosecond/foot (the inverse of the speed of light = that is!) JJ

=

=A0In a pocket or something it's about a meter because = bodies/clothes etc reduce RSSI unevenly.  The purpose of this is a couple of things, = 'patient tracking' in any sort of a facility like nursing home or hospital, and = device tracking, again in a facility with shared hardware like portable EKGs = and handheld XRays etc that get 'misplaced' and staff has to go on a hunt for.  It's also much cheaper than lorawan as BLE transmits many = times a second and runs for years while lora is built for more range and only transmits intermittently, usually 10-60 minutes to preserve battery.

We're testing mainly on dragino and milesight devices.  I'm also = having decent enough luck with mikrotik's knot which can track BLE beacons with = high enough precision.  Mikrotik has their own somewhat expensive BLE = beacons also but these are basically universal.

[RR] If you are getting inch accuracy without = addressing the synchronization problem, I’d love to hear how, especially when = there are let’s say 10 BT transmitters to “locate = simultaneously”. JJJ

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