INDOOR POSITIONING SYSTEM

• US 20150247916A1
• Filed: 09/23/2014
• Published: 09/03/2015
• Est. Priority Date: 03/03/2014
• Status: Active Grant

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Incorporated (Emerson Electric Company)
• Inventors: Bartov, Avishai, Zlotnick, Yossi
• Granted Patent: US 9,557,402 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G01S 11/16 using difference in transit time between electrical and acoustic signals
• CPC Class Codes: G01S 5/02585 at least one of the measurements being a non-radio measurement
• CPC Class Codes: G01S 5/30 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04W 56/001 Synchronization between nodes

Abstract

An indoor position system, includes a plurality of anchor stations each configured to transmit a radio frequency signal and an acoustic signal. A mobile station includes a radio frequency receiver configured to receive a radio frequency signal from at least one of the plurality of anchor stations and an acoustic receiver configured to receive an acoustic signal from at least one of the plurality of anchor stations. A processing unit is configured to determine position information of the mobile unit based upon the received radio frequency signal and acoustic signal.

Claims

1. An indoor position system, comprising:

a plurality of anchor stations, each configured to transmit a radio frequency signal and an acoustic signal;

a mobile station including;

a radio frequency receiver configured to receive a radio frequency signal from at least one of the plurality of anchor stations;

an acoustic receiver configured to receive an acoustic signal from at least one of the plurality of anchor stations; and

a processing unit configured to determine position information of the mobile unit based upon the received radio frequency signal and the acoustic signal.

2. The indoor position system of claim 1, wherein each of the plurality of anchor stations comprises:

an RF transmitter;

an acoustic transmitter;

an anchor station processing unit; and

glue logic coupled to the RF transmitter, the acoustic transmitter, and the processing unit to allow interface therebetween.

3. The indoor positioning system of claim 2, wherein the acoustic transmitter is an ultrasonic transmitter.

4. The indoor positioning system of claim 2, wherein the RF transmitter is a WirelessHART®

transmitter.

5. The indoor positioning system of claim 1, wherein the mobile station includes a temperature sensor.

6. The indoor positioning system of claim 1, wherein the acoustic receiver comprises a microphone.

7. The indoor positioning system of claim 1, and further comprising:

a central station configured to communicate with the plurality of anchor stations.

8. The indoor positioning system of claim 7, wherein the central station further comprises a central station processing unit configured to assign time division multiple access time slots for transmissions by the plurality of anchor stations.

9. The indoor positioning system of claim 8, wherein the central station processing unit is further configured to modify parameters of a mesh network based on a determined location of the mobile station.

10. The indoor positioning system of claim 1, wherein the transmitted radio frequency signal and acoustic signal are synchronized, and wherein the mobile station is configured to receive the transmitted radio frequency signal and acoustic signal from at least three of the plurality of anchor stations and calculate a position of the mobile station based on the received signals and known positions of the at least three of the plurality of anchor stations.

11. The indoor positioning system of claim 1, wherein, the transmitted radio frequency signal and acoustic signal are synchronized, wherein the mobile station is in a partially known position, and wherein the mobile station is configured to receive the transmitted radio frequency signal and acoustic signal from at least one of the plurality of anchor stations and calculate a position of the mobile station based on the received signals and known positions of the at least one of the plurality of anchor stations and the partially known position.

12. The indoor positioning system of claim 1, and further comprising a plurality of mobile stations, each mobile station configured to receive the radio frequency signal and the acoustic signal.

13. The indoor positioning system of claim 1 wherein the processing unit is located in one of the plurality of anchor stations.

14. The indoor positioning system of claim 1 wherein the processing unit is located in the mobile station.

15. The indoor positioning system of claim 1 wherein the processing unit is located in a central station.

17. The method of claim 13, wherein calculating the distance between the mobile station and the transmitting anchor station comprises:

determining a speed of sound at the mobile station; and

multiplying the speed of sound at the mobile station with the time difference between receipt of the radio frequency signal and the acoustic signal at the mobile station.

18. The method of claim 14, wherein determining the speed of sound at the mobile station comprises determining a temperature of air, and calculating the speed of sound based on the temperature.

19. The method of claim 13, and further comprising:

repeating simultaneously transmitting, receiving, determining, and calculating for at least two additional anchor stations of the plurality of anchor stations; and

determining a location of the mobile station based on the calculated distances.

22. The method of claim 18, wherein calculating the distance between the mobile station and the transmitting anchor station comprises:

determining a speed of sound at the mobile station; and

multiplying the speed of sound at the mobile station with the time difference between receipt of the radio frequency signal and the acoustic signal at the mobile station.

23. The method of claim 19, wherein determining the speed of sound at the mobile station comprises determining a temperature of air, and calculating the speed of sound based on the temperature.

24. The method of claim 18, wherein determining a location of the mobile station comprises:

locating by trilateration the mobile station using the at least three calculated distances and

the known positions of the at least three anchor stations.

16. A method of determining position of a mobile station with a plurality of anchor stations at known positions, comprising:

simultaneously transmitting a radio frequency signal and an acoustic signal from a one of the plurality of anchor stations;

receiving the radio frequency signal and the acoustic signal at the mobile station;

determining a time of receipt of the radio frequency signal and the acoustic signal at the mobile station; and

calculating a distance between the mobile station and the one of the plurality of anchor stations.

20. The method of claim 16, wherein determining a location of the mobile station comprises:

locating by trilateration the mobile station using the at least three calculated distances and the known positions of the at least three anchor stations.

21. A method of determining position of a mobile station, comprising:

receiving each of a radio frequency signal and an acoustic signal sent simultaneously from each of at least three anchor stations having known positions;

determining a time of receipt of the radio frequency signal and the acoustic signal at the mobile station for each of the at least three anchor stations;

calculating a distance between the mobile station and each of the at least three anchor stations; and

determining position of the mobile station using the at least three calculated distances.