Arrangement for, and method of, enhancing the accuracy of position detection and tracking of a mobile device movable in a venue

Patent metadata

Field	Value
Publication number	US-9891308-B2
Application number	US-201514812632-A
Country	US
Kind code	B2
Filing date	Jul 29, 2015
Priority date	Jul 29, 2015
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

A transmitter subsystem periodically transmits ranging signals at transmit times, and a receiver subsystem receives the ranging signals at receive times within a receiver window having an adjustable time duration. A real-time position of a mobile device supporting one of the subsystems is determined based on differences between the receive and transmit times. An expected arrival time for the transmitted ranging signals is determined based on the real-time position of the mobile device. Each receive time is compared with the expected arrival time to obtain a consistency rate of the ranging signals that are received by the receiver subsystem directly from the transmitter subsystem. The time duration of the receiver window is dynamically adjusted based on the consistency rate.

First claim

The invention claimed is:

1. An arrangement for enhancing accuracy of position detection and tracking of a mobile device movable in a venue, the arrangement comprising:
a real-time locationing system including a transmitter subsystem operative for periodically transmitting a plurality of ranging signals at transmit times, and a receiver subsystem spaced away from the transmitter subsystem and operative for receiving the ranging signals at receive times within a receiver window having an adjustable time duration, one of the subsystems being supported by, and movable with, the mobile device in the venue; and
a controller operatively connected to the locationing system and operative for determining a real-time position of the mobile device based on differences between the receive and transmit times, for determining an expected arrival time for the transmitted ranging signals based on the determined real-time position of the mobile device, for comparing each receive time with the expected arrival time to obtain a consistency rate of the ranging signals that are received by the receiver subsystem directly from the transmitter subsystem, and for dynamically adjusting the time duration of the receiver window based on the consistency rate.

2. The arrangement of claim 1 , wherein the other of the subsystems includes a plurality of locationing stations that are spaced apart of one another at fixed locations in the venue.

3. The arrangement of claim 1 , wherein the transmitter subsystem includes a plurality of ultrasonic transmitters that are spaced apart of one another at fixed locations in the venue, each ultrasonic transmitter being operative for transmitting the ranging signals as a series of ultrasonic pulses, and wherein the receiver subsystem includes an ultrasonic receiver mounted on the mobile device and operative for receiving the ultrasonic pulses.

4. The arrangement of claim 1 , and further comprising a host server for controlling the subsystems, and wherein the controller is mounted in at least one of the host server and the subsystems.

5. The arrangement of claim 1 , wherein the controller is configured to decrease the time duration of the receiver window when the consistency rate exceeds a reference threshold, and to increase the time duration of the receiver window when the consistency rate is less than the reference threshold.

6. The arrangement of claim 1 , wherein the controller is configured to obtain the consistency rate by determining a number and a frequency of occurrence of the ranging signals that are received by the receiver subsystem directly from the transmitter subsystem.

7. An arrangement for enhancing accuracy of position detection and tracking of a mobile device movable in a venue, the arrangement comprising:
a real-time locationing system including a transmitter subsystem having a plurality of ultrasonic transmitters that are spaced apart of one another at fixed locations in the venue, each ultrasonic transmitter being operative for periodically transmitting a plurality of ultrasonic pulses at transmit times, and a receiver subsystem having an ultrasonic receiver mounted on the mobile device away from the transmitter subsystem, the ultrasonic receiver being operative for receiving the ultrasonic pulses at receive times within a receiver window having an adjustable time duration; and
a controller operatively connected to the locationing system and operative for determining a real-time position of the mobile device based on differences between the receive and transmit times, for determining an expected arrival time for the transmitted ultrasonic pulses based on the determined real-time position of the mobile device, for comparing each receive time with the expected arrival time to obtain a consistency rate of the ultrasonic pulses that are received by the receiver subsystem from the transmitter subsystem, and for dynamically adjusting the time duration of the receiver window based on the consistency rate by decreasing the time duration of the receiver window when the consistency rate exceeds a reference threshold, and by increasing the time duration of the receiver window when the consistency rate is less than the reference threshold.

8. The arrangement of claim 7 , and further comprising a host server for controlling the subsystems, and wherein the controller is mounted in at least one of the host server and the subsystems.

9. The arrangement of claim 7 , wherein the controller is configured to obtain the consistency rate by determining a number and a frequency of occurrence of the ultrasonic pulses that are received by the receiver subsystem directly from the transmitter subsystem.

10. A method of enhancing accuracy of position detection and tracking of a mobile device movable in a venue, the method comprising:
periodically transmitting a plurality of ranging signals at transmit times by operation of a transmitter subsystem;
receiving the ranging signals at receive times within a receiver window having an adjustable time duration by operation of a receiver subsystem;
spacing the subsystems apart from each other in the venue;
supporting one of the subsystems on the mobile device for joint movement therewith in the venue;
determining a real-time position of the mobile device based on differences between the receive and transmit times;
determining an expected arrival time for the transmitted ranging signals based on the determined real-time position of the mobile device;
comparing each receive time with the expected arrival time to obtain a consistency rate of the ranging signals that are received by the receiver subsystem directly from the transmitter subsystem; and
dynamically adjusting the time duration of the receiver window based on the consistency rate.

11. The method of claim 10 , and configuring the other of the subsystems with a plurality of locationing stations that are spaced apart of one another at fixed locations in the venue.

12. The method of claim 10 , and configuring the transmitter subsystem with a plurality of ultrasonic transmitters that are spaced apart of one another at fixed locations in the venue, each ultrasonic transmitter being operative for transmitting the ranging signals as a series of ultrasonic pulses, and configuring the receiver subsystem with an ultrasonic receiver mounted on the mobile device and operative for receiving the ultrasonic pulses.

13. The method of claim 10 , and controlling the subsystems with a host server.

14. The method of claim 10 , wherein the adjusting is performed by decreasing the time duration of the receiver window when the consistency rate exceeds a reference threshold, and by increasing the time duration of the receiver window when the consistency rate is less than the reference threshold.

15. The method of claim 10 , wherein the consistency rate is obtained by determining a number and a frequency of occurrence of the ranging signals that are received directly from the transmitter subsystem.

Assignees

• Symbol Technologies Llc

Inventors

• Calvarese Russell E
• Lavery Richard J

Classifications

• G01S5/26 Primary

  Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements (G01S5/28 takes precedence) · CPC title

• G01S5/22

  Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements (G01S5/28 takes precedence) · CPC title