Q-CTRL Quantum navigation - real or BS? - Page 1
Forum section: electronics / general

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: April 18, 2025, 10:06:20 am
content: No clue if this is real but the video is making my BS detector twitch

author: iMo
author_rank: Super Contributor
timestamp: April 18, 2025, 10:13:32 am
content: https://en.wikipedia.org/wiki/Quantum_compasshttps://www.advancednavigation.com/tech-articles/the-future-of-inertial-navigation-is-classical-quantum-sensor-fusion/https://www.boeing.com/innovation/innovation-quarterly/2025/03/beyond-gps-quantum-navigation-flight-test

author: tggzzz
author_rank: Super Contributor
timestamp: April 18, 2025, 10:42:45 am
content: Whether or not it is practical, it will still have to contend with the earth's magnetic fields changing.The magnetic north pole was moving at 50km/year, but that has decreased to 35km/year.https://www.sciencealert.com/the-magnetic-north-pole-has-officially-changed-positionThe sun affects the magnetic fieldhttps://en.wikipedia.org/wiki/Geomagnetic_storm

author: AVGresponding
author_rank: Super Contributor
timestamp: April 18, 2025, 10:57:15 am
content: Quote from: tggzzz on April 18, 2025, 10:42:45 amThis^

author: voltsandjolts
author_rank: Unknown
timestamp: April 18, 2025, 12:20:36 pm
content: https://www.royalnavy.mod.uk/news/2024/october/31/20241101-royal-navy-successfully-tests-quantum-sensing-technology

author: SiliconWizard
author_rank: Super Contributor
timestamp: April 18, 2025, 03:05:08 pm
content: Oh so that's inertial navigation on steroids?

author: Marco
author_rank: Super Contributor
timestamp: April 18, 2025, 03:15:37 pm
content: Global scale changes in the magnetic field probably don't affect the local imperfections used for this. Don't think Russia or China will allow low altitude mapping of the magnetic field in their borders though.

author: tggzzz
author_rank: Super Contributor
timestamp: April 18, 2025, 03:43:16 pm
content: Quote from: Marco on April 18, 2025, 03:15:37 pmDepends on the accuracy required, and where it is required.The magnetic north pole is moving 100m/day(i.e. 35km/year).Geomagnetic storms do have significant effects. That they are monitored bymagnetometersis one indication. That they affect ground-based navigation systems used by shipping (e.g. LORAN) is another.Keep an eye onhttps://aurorawatch.lancs.ac.uk/which shows the geomagnetic field strength in Europe at ground level. You will see that variations of more than 500nT in 15µT can occur, i.e. >3%.

author: coppercone2
author_rank: Super Contributor
timestamp: April 18, 2025, 03:49:44 pm
content: Is this the secret gravity mapper they had on submarines a long time ago?I thought it was more like nasa probe B but maybe it was quantum?It sounds like its related to rydberg atoms. They are supposed to make tiny high bandwidth spectrum analyzers with them.https://ntrs.nasa.gov/api/citations/20240000362/downloads/Quantum%20Sensing%20Presentation%20Photonics%20West%202024.pdf

author: TimFox
author_rank: Super Contributor
timestamp: April 18, 2025, 03:59:33 pm
content: I grew up near the Mesabi iron ore district of northern Minnesota, where the topo maps said “declination uncertain”.

author: Marco
author_rank: Super Contributor
timestamp: April 23, 2025, 07:47:27 am
content: Quote from: tggzzz on April 18, 2025, 03:43:16 pmI assume the feature size of these disturbances is far larger than the ground feature disturbances they use, which presumably only move with the crust. Filtered out by high pass, together with North/South poling regardless of the direction.PS. I assume this is more calibration for INS than a replacement. Use the measured directional derivative of the magnetic field along the INS path, try to match that path to the geomagnetic map around where you think you are, update guess of location/orientation, repeat.

author: tggzzz
author_rank: Super Contributor
timestamp: April 23, 2025, 09:25:12 am
content: Quote from: Marco on April 23, 2025, 07:47:27 amThe issue with any filtering is, of course, setting the corner frequency to exclude "noise" and include "signal".Before being able to assess whether that was practical in this case, I would have to understand the characteristics of the signal and noise. That will partly depend on the circumstances in which the sensor is being used.One use case would with the sensor stationary. What corner frequency should be set?Another use would be moving along a (non-straight) line in which the magnetic field is unchanging.

author: Marco
author_rank: Super Contributor
timestamp: April 23, 2025, 10:10:48 am
content: Quote from: tggzzz on April 23, 2025, 09:25:12 amAn INS path with zero derivative along its path is as matchable to the geomagnetic map as any other path. You have both the shape of the path and the derivatives along it, a zero derivative straight or curved path is as unique as any other when the possible paths are all crossing small features. Only on a zero derivative featureless deathspace on the map does matching become impossible.

author: tggzzz
author_rank: Super Contributor
timestamp: April 23, 2025, 10:37:41 am
content: Quote from: Marco on April 23, 2025, 10:10:48 amI was thinking of such a zero derivative "deathspace"; that could occur in flight and without acceleration information it would cause position ambiguity. OTOH an INS will always have the initial acceleration(s) available, therefore the current velocity would be known and hence position could be inferred.Highpass filtering would make the zero derivative issueliterallymore widespread.