4 ms·

This is cool! I wouldn't be too surprised if Apple is doing something similar today. Inertial navigation systems [0] use integration to calculation position, s

This is cool! I wouldn't be too surprised if Apple is doing something similar today. Inertial navigation systems [0] use integration to calculation position, so errors add up quickly. The first in car navigation system [1] used inertial navigation. I think it used places where it knew the vehicle would (should?) stop as waypoints where the velocity could be set to zero. For example, if we think we're near a stop sign, and our calculated velocity is zero-ish, make it zero. It's pretty amazing how accurate smartphones can be when you're looking at your position while moving in an area that doesn't have GPS, probably using similar techniques. The mobile device knows (is guessing) you're in a vehicle (using measured speed, Bluetooth connection to a vehicle, the fact that you're on a road, etc.) and can snap your location to a road on a map, as well as project your position. It makes sense that inertial error could be similar for similar movement patterns, say driving over expansion joints in a concrete road. A ML model seems like a good way to try to compensate for that. The reason I wonder if Apple is doing this already is they have all the pieces...they even know which vehicle I'm in, because I pair with the Bluetooth system in both vehicles. So they could actually build a model per vehicle, which I imagine would be more accurate. They do have a patent pending for applying machine learning to the location domain, looks like this one is for GNSS though: https://patents.google.com/patent/US20200049837A1/en?oq=US20200049837A1 https://patents.google.com/patent/US20200049837A1/en?oq=US20... [0] - https://en.wikipedia.org/wiki/Inertial_navigation_system https://en.wikipedia.org/wiki/Inertial_navigation_system [1] - https://en.wikipedia.org/wiki/Etak https://en.wikipedia.org/wiki/Etak

mdturnerphys 4y ago
Actually, the first automated in-car navigation systems used mechanical couplings to a wheel to determine progress along a set route: https://arstechnica.com/cars/2020/01/turn-by-turntables-how-drivers-got-from-point-a-to-point-b-in-the-early-1900s/ https://arstechnica.com/cars/2020/01/turn-by-turntables-how-...
Animats 4y ago
Inertial navigation systems [0] use integration to calculation position, so errors add up quickly. The first in car navigation system [1] used inertial navigation. I think it used places where it knew the vehicle would (should?) stop as waypoints where the velocity could be set to zero. For example, if we think we're near a stop sign, and our calculated velocity is zero-ish, make it zero. Not quite. Etak had wheel sensors. The sensor package was two wheel sensors, a vertical reference using fluid in a cup sensed electrostatically, a 2-axis magnetometer, and a 2-axis rate gyro which used a spinning disc that deformed slightly when turning. I still have one, somewhere. All those sensors were very noisy and inaccurate. What made Etak work was map matching of turns. It tried to match its estimate of the recent path to the map data. It could get lost, but usually could find itself again after a few turns. The main problem was in grid cities. If estimated position became off by one block, turns would not help to disambiguate the problem, and so it would remain lost.
- TYPE_FASTER 4y ago
  Did you have one? Or work on it? Really cool either way. Pretty amazing how far sensor technology has come. I remember going to an Analog Devices presentation for their MEMS accelerometers around 1997. They gave out a dev board I think I might still have somewhere.

mdturnerphys 4y ago

Actually, the first automated in-car navigation systems used mechanical couplings to a wheel to determine progress along a set route: https://arstechnica.com/cars/2020/01/turn-by-turntables-how-drivers-got-from-point-a-to-point-b-in-the-early-1900s/ https://arstechnica.com/cars/2020/01/turn-by-turntables-how-...

Animats 4y ago

Inertial navigation systems [0] use integration to calculation position, so errors add up quickly. The first in car navigation system [1] used inertial navigation. I think it used places where it knew the vehicle would (should?) stop as waypoints where the velocity could be set to zero. For example, if we think we're near a stop sign, and our calculated velocity is zero-ish, make it zero. Not quite. Etak had wheel sensors. The sensor package was two wheel sensors, a vertical reference using fluid in a cup sensed electrostatically, a 2-axis magnetometer, and a 2-axis rate gyro which used a spinning disc that deformed slightly when turning. I still have one, somewhere. All those sensors were very noisy and inaccurate. What made Etak work was map matching of turns. It tried to match its estimate of the recent path to the map data. It could get lost, but usually could find itself again after a few turns. The main problem was in grid cities. If estimated position became off by one block, turns would not help to disambiguate the problem, and so it would remain lost.

TYPE_FASTER 4y ago
Did you have one? Or work on it? Really cool either way. Pretty amazing how far sensor technology has come. I remember going to an Analog Devices presentation for their MEMS accelerometers around 1997. They gave out a dev board I think I might still have somewhere.