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What about self driving cars and self driving cab services? Will they run into each other? Do they depend on GPS for navigation?

microcolonel 9y ago
If they did, they would be crashing into parked cars and buildings as well. GPS can not be the basis of fine navigation, and it does nothing for collision avoidance.
- murukesh_s 9y ago
  But how do they go to the destination? Or pickup users from their location?
- mannykannot 9y ago
  Navigation by GPS and collision avoidance are not mutually exclusive - people do it all the time. They operate at different scales.
coolspot 9y ago
I think they are mostly operating based on LIDAR data and recognition.
- cm2187 9y ago
  I thought they also relied on highly precise maps hence gps would matter. Though gps is unreliable if you need to be on the right lane of the road so I assume they have fallback mechanisms.
  - murukesh_s 9y ago
    I think they definitely require GPS or some form of satellite navigation mechanism to work. I really don't think they can use the local built-in radar to position themselves. I believe until now they have taken it for granted that GPS will always work. Theoretically we can place ourselves in the map based on visual recognition and radar, but its much more difficult than using GPS, and I don't think any of the current implementation have thought of a fallback mechanism..
    - mannykannot 9y ago
      Given a map, and starting from a known position, it is perfectly possible to know where you are by continuously updating your position by knowing your direction and distance covered, corrected by recognizing features on the map as you reach them. When done from boats or airplanes, this is known as pilotage, but it is much easier on land, where there are no winds or currents, and even easier when restricted to a road network. I don't know whether any autonomous car is equipped to do this, but it would seem to be one of the lesser technical problems of the field.
      - murukesh_s 9y ago
        I believe it will be difficult in land than it is in air or water. For e.g., how dependable would be the the recognizable features, especially in lesser known roads. Without that if the vehicle narrowly misses a road (could be due to a new road coming up or slight mismatch in the map or a temporary diversion) then the direction and distance would quickly become useless as it can't place itself anymore in the maps. Human beings can use their intuition or ask someone to correct themselves, but it would be very sophisticated to implement on a self driving machine.
        mannykannot 9y ago
        It is not correct to say that your displacement quickly becomes useless once you encounter some discrepancy in your map. It remains valid as a good estimate of your position, allowing one to recover from map errors so long as they are not pervasive. This is not a trivial programming exercise, but nor is it as difficult as many other aspects of vehicle automation.

microcolonel 9y ago

If they did, they would be crashing into parked cars and buildings as well. GPS can not be the basis of fine navigation, and it does nothing for collision avoidance.

murukesh_s 9y ago
But how do they go to the destination? Or pickup users from their location?
mannykannot 9y ago
Navigation by GPS and collision avoidance are not mutually exclusive - people do it all the time. They operate at different scales.

coolspot 9y ago

I think they are mostly operating based on LIDAR data and recognition.

cm2187 9y ago
I thought they also relied on highly precise maps hence gps would matter. Though gps is unreliable if you need to be on the right lane of the road so I assume they have fallback mechanisms.
- murukesh_s 9y ago
  I think they definitely require GPS or some form of satellite navigation mechanism to work. I really don't think they can use the local built-in radar to position themselves. I believe until now they have taken it for granted that GPS will always work. Theoretically we can place ourselves in the map based on visual recognition and radar, but its much more difficult than using GPS, and I don't think any of the current implementation have thought of a fallback mechanism..
  - mannykannot 9y ago
    Given a map, and starting from a known position, it is perfectly possible to know where you are by continuously updating your position by knowing your direction and distance covered, corrected by recognizing features on the map as you reach them. When done from boats or airplanes, this is known as pilotage, but it is much easier on land, where there are no winds or currents, and even easier when restricted to a road network. I don't know whether any autonomous car is equipped to do this, but it would seem to be one of the lesser technical problems of the field.
    - murukesh_s 9y ago
      I believe it will be difficult in land than it is in air or water. For e.g., how dependable would be the the recognizable features, especially in lesser known roads. Without that if the vehicle narrowly misses a road (could be due to a new road coming up or slight mismatch in the map or a temporary diversion) then the direction and distance would quickly become useless as it can't place itself anymore in the maps. Human beings can use their intuition or ask someone to correct themselves, but it would be very sophisticated to implement on a self driving machine.
      - mannykannot 9y ago
        It is not correct to say that your displacement quickly becomes useless once you encounter some discrepancy in your map. It remains valid as a good estimate of your position, allowing one to recover from map errors so long as they are not pervasive. This is not a trivial programming exercise, but nor is it as difficult as many other aspects of vehicle automation.