Positioning methods and systems
Methods are provided for determining a positioning of a portable device including first and second sensor(s) each having a confidence. These methods include: receiving first and second signals from the first and second sensor(s), respectively; generating positional data representing positional conditions of the portable device and including first and second positional data respectively from the first and second signals, by modelling the received signals based on predefined models defining a correspondence between predefined signals and predefined positional data; comparing the first and second positional data to determine a difference between them; adjusting the confidence of the sensors by determining a new confidence depending on a previous confidence and the determined difference between positional data; weighting the generated positional data depending on corresponding confidences; and determining the positioning of the portable device based on the weighted generated positional data. Computer programs and systems suitable for performing such methods are also provided.
1. A method for determining a positioning of a portable device comprising a plurality of sensors including first one or more sensors and second one or more sensors, each of the sensors in the plurality of sensors having a corresponding confidence, the method comprising:
sensing first sensor signals by at least a first one of the first one or more sensors and sensing second sensor signals by a second one of the second one or more sensors; and, by a processor
receiving the first and second sensor signals from the plurality of sensors;
generating positional data including first and second positional data respectively from the first and second sensor signals, said positional data representing positional conditions of the portable device, by modelling the received sensor signals based on one or more predefined models including one or more signal models defining a correspondence between predefined sensor signals and predefined positional data;
comparing the first positional data with the second positional data to determine a difference between the first and second positional data;
adjusting, for each of the first and second one or more sensors, the corresponding confidence of the corresponding sensor by determining an adjusted confidence value depending on the corresponding confidence value of the sensor and the determined difference between the first and second positional data;
weighting the generated positional data depending on one or both the corresponding or the adjusted confidences of the corresponding sensors in the plurality of sensors; and
determining the positioning of the portable device based on the weighted generated positional data.
2. A method according to claim 1 , each of the sensors in the plurality of sensors corresponding to one of the following types of sensors: accelerometer, gyroscope, magnetometer, Wi-Fi sensor, Bluetooth sensor.
3. A method according to claim 1 , the positional conditions of the portable device including one or more of: positions and/or orientations and/or walking steps and/or trajectory and/or displacement of the portable device.
4. A method according to claim 1 , the adjusting the confidences of the first and second one or more sensors comprising
determining which of the first and second one or more sensors have higher or lower confidence in comparison with the other of the first and second one or more sensors, and decreasing the lower of the confidences proportionally to the difference between the first and second positional data.
5. A method according to claim 1 , the adjusting the confidences of the first and second one or more sensors comprising
determining whether the difference between the first and second positional data is within a predefined deviation acceptability range, in which case the confidences are kept substantially unvaried.
6. A method according to claim 1 , the modelling the received sensor signals comprising
for each of the sensors in the plurality of sensors, determining which of the signal models best matches the signals from the sensor depending on a comparison between the signals from the sensor and the predefined sensor signals of corresponding signal models, and determining a matching level of said best matching signal model; and
the adjusting the confidences of the first and second one or more sensors comprises adjusting, for each of the first and second one or more sensors, the confidence of the sensor further depending on corresponding matching level.
7. A method according to claim 6 , further comprising determining whether the matching level is within a predefined matching acceptability range, in which case an increase is induced in the confidence, or outside a predefined matching acceptability range, in which case a decrease is induced in the confidence.
8. A method according to claim 7 , the higher the matching level within a predefined matching acceptability range is, the higher the induced increase is; and the lower the matching level within a predefined matching acceptability range is, the lower the induced increase is.
9. A method according to claim 7 , the higher the matching level outside a predefined matching acceptability range is, the lower the induced decrease is; and the lower the matching level outside a predefined matching acceptability range is, the higher the induced decrease is.
10. A method according to claim 1 , further comprising
determining whether the first positional data includes a first series of positional data with abnormalities, and whether the second positional data includes a second series of positional data with abnormalities, said abnormalities corresponding to one or more of outliers and/or signal values outside an expectedness range and/or signal gaps in the corresponding series; and
determining, for each of the first and second series of positional data, an abnormality level depending on the abnormalities detected in the series; and
adjusting the confidence of each of the first and second one or more sensors comprises adjusting, for each of the first and second one or more sensors, the confidence of the corresponding sensor further depending on corresponding abnormality level.
11. A method according to claim 10 , the predefined models further including expectedness models including predefined series of positional data satisfying predefined expectedness conditions; and
the abnormalities corresponding to one or more of outliers and/or signal values outside the expectedness range and/or signal gaps are determined by comparing corresponding series of positional data to predefined series of positional data of the corresponding expectedness models.
12. A method according to claim 10 , further comprising determining whether the abnormality level is within a predefined abnormality acceptability range, in which case an increase is induced in the confidence, or outside a predefined abnormality acceptability range, in which case a decrease is induced in the confidence.
13. A method according to claim 12 , the higher the abnormality level within a predefined abnormality acceptability range is, the lower the induced increase is; and the lower the abnormality level within a predefined abnormality acceptability range is, the higher the induced increase is.
14. A method according to claim 12 , the higher the abnormality level outside a predefined abnormality acceptability range is, the higher the induced decrease is; and
the lower the abnormality level outside a predefined abnormality acceptability range is, the lower the induced decrease is.
15. A method according to claim 1 , further comprising
verifying, for each of the first and second one or more sensors, whether the confidence of the corresponding sensor is outside a predefined confidence acceptability range, in which case the confidence of the sensor is reduced to an extent that minimizes or eliminates the influence of the signals from said sensor in the determination of the positioning of the portable device.
16. A method according to claim 1 , further comprising storing at least some of one or more of the predefined models, received sensor signals, determined positional data and/or sensor confidences in a knowledge base or repository.
17. A method according to claim 16 , further comprising adjusting at least some of one or more of the stored predefined models depending on at least some of the received sensor signals, determined positional data and/or sensor confidences stored in the knowledge base.
18. A method according to claim 1 , the weighting the generated positional data comprising
weighting the generated positional data with respective weights each depending on the confidence of corresponding sensor in the plurality of sensors such that the higher the confidence of a sensor is, the higher the corresponding weight is determined, and the lower the confidence of a sensor is, the lower the corresponding weight is determined.
19. A computer program comprising program instructions for causing a computing system to perform a method according to claim 1 for determining a positioning of a portable device.
20. A computing system for determining a positioning of a portable device, the computing system comprising a memory and a processor, embodying instructions stored in the memory and executable by the processor, the instructions comprising functionality to execute a method according to claim 1 for determining a positioning of a portable device.