Methods and systems for combining sensor data to determine vehicle movement information
According to some embodiments of the invention, movement measurements may be obtained from a movement sensor (e.g., an accelerometer) of a mobile device in a vehicle. In addition, location measurements may be obtained from a location sensor (e.g., a GPS) of the mobile device in the vehicle. The movement measurements and the location measurements may be cross-referenced to each other to remove erroneous measurements, such as physically impossible measurements. The remaining measurements may be used to draw conclusions about the movements or locations, such as to identify a movement event (e.g., a braking event, an acceleration event, or the like).
1. A method comprising:
operating a movement sensor of a mobile device disposed in a vehicle to obtain a plurality of movement measurements;
operating a location sensor of the mobile device disposed in the vehicle to obtain a plurality of location measurements;
verifying, by a processor of the mobile device, a portion of the plurality of movement measurements using the plurality of location measurements;
removing, by the processor, one or more movement measurements that are not verified from the plurality of movement measurements to provide a set of remaining movement measurements; and
determining, by the processor, a movement event for the vehicle using the set of remaining movement measurements.
2. The method of claim 1 , further comprising:
using two or more approaches to verifying the portion of the plurality of movement measurements, wherein verifying using the plurality of location measurements is used by at least one of the approaches,
wherein removing the one or more movement measurements that are not verified from the portion of the plurality of movement measurements to provide the set of remaining movement measurements comprises, for the plurality of movement measurements, independently using each of the approaches to remove the one or more movement measurements that are not verified.
3. The method of claim 1 , wherein verifying the portion of the plurality of movement measurements comprises:
determining, by the processor, a movement measurement of a first portion of the plurality of movement measurements as not verified based on a comparison of an accuracy estimate of the movement measurement and a first threshold.
4. The method of claim 1 , wherein verifying the portion of the plurality of movement measurements comprises:
applying, by the processor, a first set of rules to two movement measurements of a second portion of the plurality of movement measurements to determine that the two movement measurements are not both physically possible; and
determining, by the processor, one of the two movement measurements determined to not be physically possible as not verified.
5. The method of claim 1 , wherein verifying the portion of the plurality of movement measurements comprises:
determining, by the processor, a third portion of the plurality of movement measurements having duplicate values as not verified.
6. The method of claim 5 , wherein the duplicate values of the third portion of the plurality of movement measurements are time values.
7. The method of claim 5 , wherein the duplicate values of the third portion of the plurality of movement measurements are location values.
8. The method of claim 1 , wherein verifying the portion of the plurality of movement measurements comprises:
applying, by the processor, a second set of rules to a fourth portion of the plurality of movement measurements to determine that each movement measurement of the fourth portion of the plurality of movement measurements has location values that are clustered; and
determining, by the processor, the fourth portion of the plurality of movement measurements as not verified.
9. The method of claim 1 , further comprising:
grouping each of the set of remaining movement measurements into groups based on a collection time for the set of remaining movement measurements, the grouping resulting in a plurality of movement measurement groups, wherein the set of remaining movement measurements each have a speed component;
for a first group of the plurality of movement measurement groups, using the speed component of each movement measurement of the first group to determine a plurality of acceleration rates describing changes in the speed component;
applying a second threshold to the acceleration rates; and
removing two or more movement measurements from the first group based on the second threshold being applied to the acceleration rates associated with the two or more movement measurements.
10. A device comprising:
a memory; and
a processor coupled to the memory, wherein the processor is configured to perform operations including:
operating a movement sensor of a mobile device disposed in a vehicle to obtain a plurality of movement measurements;
operating a location sensor of the mobile device disposed in the vehicle to obtain a plurality of location measurements;
verifying a portion of the plurality of movement measurements using the plurality of location measurements;
removing one or more movement measurements that are not verified from the plurality of movement measurements to provide a set of remaining movement measurements; and
determining a movement event for the vehicle using the set of remaining movement measurements.
11. The device of claim 10 , wherein the processor is further configured to:
use two or more approaches to verifying the portion of the plurality of movement measurements, wherein verifying using the plurality of location measurements is used by at least one of the approaches,
wherein removing the one or more movement measurements that are not verified from the plurality of movement measurements to provide the set of remaining movement measurements comprises, for the plurality of movement measurements, independently using each of the approaches to remove the one or more movement measurements that are not verified.
12. The device of claim 10 , wherein verifying the portion of the plurality of movement measurements comprises:
determining a movement measurement of a first portion of the plurality of movement measurements as not verified based on a comparison of an accuracy estimate of the movement measurement and a first threshold.
13. The device of claim 10 , wherein verifying the portion of the plurality of movement measurements comprises:
applying a first set of rules to two movement measurements of a second portion of the plurality of movement measurements to determine that the two movement measurements are not both physically possible; and
determining one of the two movement measurements determined to not be physically possible as not verified.
14. The device of claim 10 , wherein verifying the portion of the plurality of movement measurements comprises:
determining a third portion of the plurality of movement measurements having duplicate values as not verified.
15. The device of claim 14 , wherein the duplicate values of the third portion of the plurality of movement measurements are time values.
16. The device of claim 14 , wherein the duplicate values of the third portion of the plurality of movement measurements are location values.
17. The device of claim 10 , wherein verifying the portion of the plurality of movement measurements comprises:
applying a second set of rules to a fourth portion of the plurality of movement measurements to determine that each movement measurement of the fourth portion of the plurality of movement measurements has location values that are clustered; and
determining the fourth portion of the plurality of movement measurements as not verified.
18. The device of claim 10 , wherein the processor is further configured to:
group each of the set of remaining movement measurements into groups based on a collection time for the set of remaining movement measurements, the grouping resulting in a plurality of movement measurement groups, wherein the set of remaining movement measurements have a speed component;
for a first group of the plurality of movement measurement groups, use the speed component of each movement measurement of the first group to determine a plurality of acceleration rates describing changes in the speed component;
apply a second threshold to the acceleration rates; and
remove two or more movement measurements from the first group based on the second threshold being applied to the acceleration rates associated with the two or more movement measurements.