3 ms·
Definitely. GPS can't be relied on: there are lots of places with naturally bad reception and the military sometimes tests GPS jammers, like during the recent
by Slansitartop 9y ago
Definitely. GPS can't be relied on: there are lots of places with naturally bad reception and the military sometimes tests GPS jammers, like during the recent exercise.
It's interesting to note that the first in-car navigation system used no GPS: it relied solely on inertial navigation and map-fitting to determine its location. For navigation, an autonomous car needs something like that as backup for GPS. All the actual driving needs to be done with on-board sensors, though.
- cobookman 9y agoDead reckoning is actually fairly accurate if done right. I'd be surprised if the lidar units aren't being used for a similar algorithm.
- nradov 9y agoDoing dead reckoning "right" over an extended distance requires extremely expensive laser ring gyroscopes. It's going to be a long time before those (or something with similar accuracy) will be affordable for consumer use.
- majormajor 9y agoWould a self-driving car need perfect dead reckoning? I was able to update my assumptions about my distance and location based on street signs before I had GPS...
- com2kid 9y agoCouldn't the device correct using local land marks? A minimal offline map, maybe even just topographic, that shouldn't change too often. "Expected hill was crested 5 meters sooner then expected, update estimated position accordingly".
- nradov 9y agoIf you have local land marks then you don't really need dead reckoning at all. Cheap dead reckoning sensors have so much error and drift right now as to be mostly useless for driving. The expensive sensors work but aren't economical for cheap passenger cars.
- Slansitartop 9y agoHere's the system I was talking about. It used dead reckoning and landmarks (turns) to periodically re-calibrate the fix. This was all done with 80s technology. https://www.fastcompany.com/3047828/who-needs-gps-the-forgotten-story-of-etaks-amazing-1985-car-navigation-system https://www.fastcompany.com/3047828/who-needs-gps-the-forgot... Live demo: https://www.youtube.com/watch?v=CHCCjlSWbHE https://www.youtube.com/watch?v=CHCCjlSWbHE > Cheap dead reckoning sensors have so much error and drift right now as to be mostly useless for driving. I don't think anyone's saying that it would be used for the driving part (i.e. car control), just as an option for orienting the car in the wider world beyond its direct perception.