Position estimation apparatus, position estimation system, position estimation method and recording medium for position estimation
The present invention provides a position estimation apparatus, a position estimation system, and a position estimation method that can estimate, with high accuracy, the position of a wireless device, the position of which is unknown, as well as a recording medium for position estimation. The position estimation apparatus comprises: a data collection means for collecting measurement data related to an inter-device distance between one wireless device and another wireless device, the inter-device distance being measured by the one wireless device, and measurement data related to the reliability of the inter-device distance between the one wireless device and the other wireless device, the reliability being calculated by the one wireless device; and a wireless-device position estimation means for estimating the position of a wireless device, the position of which is unknown, on the basis of the measurement data collected by the data collection means and the previously collected measurement data related to the measured inter-device distance between the one wireless device and the other wireless device, and the reliability of the inter-device distance.
1. A position estimation apparatus comprising:
a data collection unit which collects measurement data related to an inter-device distance measured by one wireless device between the one wireless device and another wireless device, and related to reliability of the inter-device distance to the another wireless device, calculated by the one wireless device;
a wireless-device position estimation unit which estimates a position of a position-unknown wireless device, based on measurement data collected by the data collection unit, and previously collected measurement data related to a measured inter-device distance between one wireless device and another wireless device and related to reliability of the inter-device distance; and
a geometric correction unit for correcting a geometric error remaining at the corrected unknown-wireless-device position, by using position information of an absolute-position-known wireless device among the wireless devices, the updated inter-device distance, and the updated reliability of the inter-device distance.
2. A position estimation apparatus comprising:
an inter-wireless-device distance update unit which collects measurement data related to an inter-device distance measured by one wireless device between the one wireless device and another wireless device, and related to reliability of the inter-device distance to the another wireless device, calculated by the one wireless device, and updating an accumulated inter-device distance and reliability of the inter-device distance;
a wireless-device position estimation unit which estimates a position of a position-unknown wireless device, based on measurement data collected by the inter-wireless-device distance update unit, and previously collected measurement data related to a measured inter-device distance between one wireless device and another wireless device and related to reliability of the inter-device distance; and
a geometric correction unit for correcting a geometric error remaining at the corrected unknown-wireless-device position, by using position information of an absolute-position-known wireless device among the wireless devices, the updated inter-device distance, and the updated reliability of the inter-device distance.
3. The position estimation apparatus according to claim 2 , wherein the wireless-device position estimation unit sorts order of a wireless device to be position-estimated, based on a distance between the wireless device and a position-known wireless device.
4. The position estimation apparatus according to claim 3 , wherein, as the sorting method, estimation is performed in order from a wireless device having a smallest difference between maximum and minimum distances to a position-known wireless device.
5. The position estimation apparatus according to claim 3 , wherein, as the sorting method, estimation is performed in order from a wireless device having a smallest average distance to a position-known wireless device.
6. The position estimation apparatus according to claim 2 , further comprising a weighting correction unit for correcting the estimated unknown-wireless-device position, by using the updated inter-device distance and the updated reliability of the inter-device distance.
7. A position estimation system comprising:
a plurality of wireless devices for measuring an inter-device distance between a wireless device and another wireless device by transmitting and receiving a radio signal to and from each other, calculating, based on reception quality of the radio signal used in measurement of the inter-device distance, reliability of the inter-device distance, and outputting the measured inter-device distance and the calculated reliability of the inter-device distance at a predetermined cycle; and
a position estimation apparatus for collecting the measured inter-device distance and the calculated reliability of the inter-device distance from the plurality of wireless devices, calculating a device relative position of each of the wireless devices, and outputting a device-position estimation result, wherein
the position estimation apparatus comprises:
an inter-wireless-device distance update unit which collects measurement data related to a measured inter-device distance between a wireless device and another wireless device and related to reliability of the inter-device distance, and updating an accumulated inter-device distance and reliability of the inter-device distance; and
a wireless-device position estimation unit which estimates a position of a position-unknown wireless device, based on measurement data collected by the inter-wireless-device distance update unit and previously collected measurement data related to a measured inter-device distance between a wireless device and another wireless device and related to reliability of the inter-device distance,
wherein the position estimation apparatus further comprises a weighting correction unit which corrects the estimated unknown-wireless-device position, by using the updated inter-device distance and the updated reliability of the inter-device distance,
wherein the position estimation apparatus further comprises a geometric correction unit which corrects a geometric error remaining at the corrected unknown-wireless-device position, by using position information of an absolute-position-known wireless device among the wireless devices, the updated inter-device distance, and the updated reliability of the inter-device distance.
8. A position estimation method comprising:
collecting measurement data related to a measured inter-device distance between a wireless device and another wireless device and related to reliability of the inter-device distance, and updating an accumulated inter-device distance and reliability of the inter-device distance; and
estimating a position of a position-unknown wireless device, based on the collected measurement data, and previously collected measurement data related to a measured inter-device distance between a wireless device and another wireless device and related to reliability of the inter-device distance,
wherein the estimated unknown-wireless-device position is corrected by using the updated inter-device distance and the updated reliability of the inter-device distance,
wherein a geometric error remaining at the corrected unknown-wireless-device position is corrected by using position information of an absolute-position-known wireless device among the wireless devices, the updated inter-device distance, and the updated reliability of the inter-device distance.
9. A non-transitory computer-readable recording medium for position estimation that records a position estimation program causing a processor to:
collect measurement data related to a measured inter-device distance between a wireless device and another wireless device and related to reliability of the inter-device distance, and execute updating processing on an accumulated inter-device distance and reliability of the inter-device distance,
execute estimation processing on a position of a position-unknown wireless device, based on the collected measurement data, and previously collected measurement data related to a measured inter-device distance between a wireless device and another wireless device and related to reliability of the inter-device distance,
execute correction processing on the estimated unknown-wireless-device position, by using updated inter-device distance and updated reliability of the inter-device distance, and
execute correction processing on a geometric error remaining at corrected unknown-wireless-device position, by using position information of an absolute-position-known wireless device among the wireless devices, the updated inter-device distance, and the updated reliability of the inter-device distance.