Vehicular localization systems, methods, and controls
Localization systems, including road surface-based localization systems, are disclosed that may work in conjunction with less precise systems, such as GPS, to accurately locate a vehicle on a road segment. Methods and apparatus are disclosed for the identification and selection of landmarks, including road surface-based landmarks.
1. A method for identifying landmarks associated with a surface of a road segment, the method comprising:
with a GPS receiver, determining that a first vehicle is traversing the surface of the road segment;
while the first vehicle traverses the road segment, receiving a sequence of data from a sensor located in the first vehicle, wherein the sensor is selected from the group consisting of an accelerometer, an inertial motion unit, and a displacement sensor, wherein the sequence of data corresponds to vertical motion of a portion of the first vehicle induced by the surface of the road segment, and wherein the portion is selected from the group consisting of a wheel, a wheel assembly and a vehicle body;
dividing the sequence of data into a first series of snippets, wherein each snippet in the first series is associated with a portion of the road segment;
determining a distinctiveness score for each snippet;
identifying a first snippet, wherein the first snippet has a highest distinctiveness score of the first series of snippets;
designating a first portion of the surface of the road segment associated with the first snippet as a first landmark;
removing, from the first series of snippets, at least the first snippet and any snippet that overlaps with the first snippet, to form a second series of snippets;
identifying a second snippet, wherein the second snippet has a highest distinctiveness score of the second series of snippets;
designating a second portion of the road segment associated with the second snippet as a second landmark;
storing, in computer memory, information characterizing the first landmark and the second landmark, and a location of the first landmark relative to a location of the second landmark;
determining a location of a second vehicle based at least on a portion of the information while the second vehicle is traversing the surface of the road segment; and
controlling at least one system of the second vehicle based on the determined location.
2. The method of claim 1 , further comprising locating the second vehicle relative to the first and the second landmarks based on at least a portion of the information.
3. The method of claim 1 , wherein the location of the first landmark is stored as a relative location with respect to a location of a previously identified landmark.
4. The method of claim 1 , wherein the at least one system comprises at least one of the following: an active suspension system of the second vehicle, a propulsion system of the second vehicle, and an autonomous steering and driving system of the second vehicle.
5. The method of claim 1 , wherein the at least one system comprises an active suspension system of the second vehicle, and wherein controlling the active suspension system comprises adjusting a damping curve of the active suspension system.
6. A method of creating a database of road surface landmarks associated with a road segment, the method comprising:
operating a first vehicle to traverse a road segment;
receiving a sequence of data sensed by a sensor located in the first vehicle during the traversal of the road segment by the first vehicle, wherein the sensor is selected from the group consisting of an accelerometer, an inertial motion unit, and a displacement sensor, wherein the sequence of data corresponds to road surface information based on vertical motion of a portion of the first vehicle induced by a surface of the road segment, and wherein the portion is selected from the group consisting of a wheel, a wheel assembly and a vehicle body;
dividing the sequence of data into a first series of overlapping snippets, wherein each snippet in the first series of overlapping snippets is associated with a portion of the road segment;
determining a distinctiveness score for each snippet;
identifying a first snippet, wherein the first snippet has a highest distinctiveness score of the first series of overlapping snippets;
designating a first portion of the surface of the road segment associated with the first snippet as a first landmark;
removing, from the first series of overlapping snippets, at least the first snippet and any snippet that overlaps with the first snippet, to form a second series of overlapping snippets;
identifying a second snippet, wherein the second snippet has a highest distinctiveness score of the second series of overlapping snippets;
designating a second portion of the road segment associated with the second snippet as a second landmark; and
storing, in the database, information characterizing the first landmark and the second landmark.
7. The method of claim 6 , further comprising converting the sequence of data from a time domain to a distance domain, wherein the sequence of data is collected periodically at regular time intervals.
8. The method of claim 7 , wherein the conversion from the time domain to the distance domain is based on vehicle speed.
9. The method of claim 6 , wherein the first series of overlapping snippets have a snippet length adjusted based on vehicle speed.
10. The method of claim 6 , wherein the distinctiveness score is for each snippet is determined, with an algorithm, based at least partially on one of vehicle speed and a frequency of the sequence of data.
11. The method of claim 6 , wherein the distinctiveness score for each snippet is determined based in part on applying a filter directed to a first frequency range.
12. The method of claim 6 , wherein a relative distance between the first landmark and the second landmark is stored in the database.
13. The method of claim 6 , further comprising transmitting the sequence of data to a remote localization controller.
14. A method of establishing a road surface landmark associated with a road segment the method comprising:
operating a first vehicle to traverse a road segment;
receiving a sequence of data sensed by at least one sensor located in the first vehicle during the traversal of the road segment by the first vehicle, wherein the at least one sensor is selected from the group consisting of an accelerometer, an inertial motion unit, and a displacement sensor, wherein the sequence of data corresponds to a vertical motion of a portion of the first vehicle induced by a surface of the road segment, and wherein the portion is selected from the group consisting of a wheel, a wheel assembly and a vehicle body;
dividing the sequence of data into a first series of overlapping snippets, wherein each snippet in the first series of overlapping snippets is associated with a portion of the road segment;
determining a distinctiveness score for each snippet of the first series of overlapping snippets;
identifying a first snippet, wherein the first snippet has a highest distinctiveness score of the first series of overlapping snippets;
designating a first portion of the surface of the road segment associated with the first snippet to be a first landmark; and
storing information about the first landmark in a database.
15. The method of claim 14 , further comprising using at least a portion of the information to determine a location of a second vehicle as the second vehicle traverses the road segment.
16. The method of claim 14 , further comprising transmitting the sequence of data to a remote localization controller.