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What exactly is 'UWB functionality'? Are they using UWB for RF localization? I assume you would need multiple beacons for that? Are they using the phone as a

What exactly is 'UWB functionality'? Are they using UWB for RF localization? I assume you would need multiple beacons for that? Are they using the phone as a single beacon? Wouldn't this just give you a radius rather than a location?

polishdude20 5y ago
Yeah maybe. But from what I've heard the product can do, it'll guide you with a heading pointing towards where the product is. It may be that the iPhone has some sort of dual antenna functionality where the difference in time between signals being recieved can be used to find the direction.
- DoingIsLearning 5y ago
  My initial intuition was that uwb localization was still in research paper territory. The only previous commercial example I can think of is those Razer Hydra gaming controllers. Pretty interesting that is come around to a mass consumer product with Apple.
- GeorgeTirebiter 5y ago
  UWB works like this: most of the time, the UWB chip ('U1') is 'off' because it draws a lot more energy than BLE does. BLE's signal strength gives a measure of distance -- but generally BLE uses 1 antenna, so what you get is a signal strength for some unit within a radius of a sphere (again, approximately). When the BLE signal strength is considered 'strong enough', the iPhone commands the BLE to send a 'turn on the UWB in the tag' command. Now, the tag sends a UWB burst. Like this: https://media.nxp.com/static-files/34261e70-6908-4e13-8eec-8361dff859a3 https://media.nxp.com/static-files/34261e70-6908-4e13-8eec-8... The time-of-flight is measured, and the precise distance is now known. More detail is in this presentation https://media.nxp.com/static-files/8cf4341d-f16d-4971-9b92-c003c39bfa22 https://media.nxp.com/static-files/8cf4341d-f16d-4971-9b92-c... Further, UWB signal strength helps determine the direction. Above is the FiRa Consortium's literature. NXP makes a similar chip to Apple's "U1" UWB chip -- however, sigh, the standards are NOT compatible. Yes, they are both UWB and use the FCC rules for UWB RF requirements (frequencies, power, etc) -- but for reasons I do not understand, they are different elsewhere (Protocols? I don't know).
SilverRed 5y ago
With just one phone your phone can point an arrow in the direction of the airtag and give you a distance to it. Tested it out a bit and it works pretty well but its short range.

polishdude20 5y ago

Yeah maybe. But from what I've heard the product can do, it'll guide you with a heading pointing towards where the product is. It may be that the iPhone has some sort of dual antenna functionality where the difference in time between signals being recieved can be used to find the direction.

DoingIsLearning 5y ago
My initial intuition was that uwb localization was still in research paper territory. The only previous commercial example I can think of is those Razer Hydra gaming controllers. Pretty interesting that is come around to a mass consumer product with Apple.
GeorgeTirebiter 5y ago
UWB works like this: most of the time, the UWB chip ('U1') is 'off' because it draws a lot more energy than BLE does. BLE's signal strength gives a measure of distance -- but generally BLE uses 1 antenna, so what you get is a signal strength for some unit within a radius of a sphere (again, approximately). When the BLE signal strength is considered 'strong enough', the iPhone commands the BLE to send a 'turn on the UWB in the tag' command. Now, the tag sends a UWB burst. Like this: https://media.nxp.com/static-files/34261e70-6908-4e13-8eec-8361dff859a3 https://media.nxp.com/static-files/34261e70-6908-4e13-8eec-8... The time-of-flight is measured, and the precise distance is now known. More detail is in this presentation https://media.nxp.com/static-files/8cf4341d-f16d-4971-9b92-c003c39bfa22 https://media.nxp.com/static-files/8cf4341d-f16d-4971-9b92-c... Further, UWB signal strength helps determine the direction. Above is the FiRa Consortium's literature. NXP makes a similar chip to Apple's "U1" UWB chip -- however, sigh, the standards are NOT compatible. Yes, they are both UWB and use the FCC rules for UWB RF requirements (frequencies, power, etc) -- but for reasons I do not understand, they are different elsewhere (Protocols? I don't know).

SilverRed 5y ago

With just one phone your phone can point an arrow in the direction of the airtag and give you a distance to it. Tested it out a bit and it works pretty well but its short range.