Accurate geographic tracking of mobile devices

• US 10,642,560 B2
• Filed: 02/11/2016
• Issued: 05/05/2020
• Est. Priority Date: 02/13/2015
• Status: Active Grant

• Current Assignee: Position Imaging, Inc.
• Original Assignee: Position Imaging, Inc.
• Inventors: Hill, Edward L., Bilbrey, Brett, Deffebach, III, Harry Lee, Komoni, Krenar
• Primary Examiner(s): Gregory, Bernarr E
• Assistant Examiner(s): Mull, Fred H
• Application Number:
  US15/041,405
• Publication Number:
  US 20160238692A1
• Time in Patent Office: 1,545 Days
• CPC Class Codes: G01S 19/48 by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
• CPC Class Codes: G01S 2205/01 specially adapted for specific applications
• CPC Class Codes: G01S 2205/02 Indoor
• CPC Class Codes: G01S 5/0072 Transmission between mobile stations, e.g. anti-collision systems
• CPC Class Codes: G01S 5/012 Identifying whether indoors or outdoors
• CPC Class Codes: G01S 5/0284 Relative positioning
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G06F 3/14 Digital output to display device ; Cooperation and interconnection of the display device with other functional units

Abstract

A tracking system is described having at least two mobile transmitter/receivers (“transceivers”) which sense and respond to at least one tracking transceiver. The signals sent to and received from the mobile transceivers are analyzed to get a distance (range) that each is from the tracking transceiver. This can be converted into a position relative to the mobile transceivers. If there are enough transceivers, and at least one knows its absolute location, the absolute location of the mobile transceivers may be determined. Existing smartphones, cellphones, WI-FI® wireless standard routers, BLUETOOTH® wireless standard devices, and near-field devices that have on-board processors, can be modified to run executable code to implement the current invention. They may communicate using at least one of the modalities for tracking. These may be implemented in tracking the position and orientation of moving devices, such as a head-mounted display for virtual/Augmented Reality, automobiles, packages in a package delivery truck. The system may also be implemented to identify and keep track of the last known location of various objects.

Claims

1. A system for tracking mobile devices in real time comprising:

first and second multifrequency radio frequency (RF) transmitters disposed at known positions, each multifrequency RF transmitter transmitting a multifrequency RF signal conveying identification and the known position of that multifrequency RF transmitter; and

a mobile device with a known heading and orientation and disposed within a maximum unambiguous range of the multifrequency RF transmitters, the mobile device comprising;

a user display that provides images to a user as viewed from a viewpoint;

at least two mobile display antennae, each antenna mounted on the display at a known spatial separation from each other antenna, the at least two mobile display antennae being adapted to receive the multifrequency RF signals transmitted by the first and second multifrequency RF transmitters;

a receiver circuit having a carrier recovery circuit that functions to synchronize the multifrequency RF signals received by each of the at least two mobile display antennae, compare phases of multiple frequencies of each multifrequency RF signal received by each of the at least two mobile display antennae and determine phase differences between the compared phases; and

a processor, coupled to the receiver circuit, programmed to;

receive the phase differences from the receiver circuit;

calculate a distance from each multifrequency RF transmitter to each of the at least two mobile display antennae based on the phase differences;

calculate a position of each of the at least two mobile display antennae based on the calculated distances, the known positions of the multifrequency RF transmitters, the known spatial separation between the at least two mobile display antennae and the known heading and orientation of the mobile device; and

cause a change in the viewpoint of the images provided to the user on the user display of the mobile device using the calculated positions of each of the at least two mobile display antennae.

2. The system of claim 1, wherein the carrier recovery circuit comprises:

a delay locked loop; and

a phase comparator for determining a phase difference of the multifrequency RF signals received by each antenna.

3. The system of claim 1, wherein the receiver circuit comprises:

an amplifier circuit to amplify each multifrequency RF signal;

a down-converter to reduce a frequency of each amplified signal;

a filter to filter each down-converted signal; and

an analog-to-digital converter (ADC), that samples each filtered signal into digital data and sends the digital data to a processor.

4. The system of claim 1, wherein the processor runs executable code to de-spread each multifrequency RF signal using a particular pseudo-noise (PN) sequence code.

5. The system of claim 1, wherein the processor utilizes parallel digital filters to separate multifrequency components of each received multifrequency RF signal into a plurality of separated signals to determine a phase of at least two separated signals and compare the phases using a differential phase comparator.

6. The system of claim 1, further comprising:

a third multifrequency RF transmitter, wherein the processor of the mobile device calculates a position of the third multifrequency RF transmitter relative to the at least two mobile display antennae based on phase difference of arrival of a multifrequency RF signal transmitted by the third multifrequency RF transmitter and received at the at least two mobile display antennae, and the known spatial separation of the at least two mobile display antennae on the display.

7. The system of claim 6 wherein the third multifrequency RF transmitter is an RFID transmitter that receives and retransmits multifrequency signals transmitted from the mobile device.

8. The system of claim 7, wherein the transmitters and the receiver circuit utilize ultra-wideband communication to determine time of arrival for distances between each transmitter and the at least two mobile display antennae.

9. The system of claim 6, wherein the calculated position of the third RF transmitter is registered with images shown in the user display.

10. The system of claim 6, wherein the third RF transmitter is a peripheral device that interacts with the mobile device.

11. The system of claim 1, wherein the mobile device is a head mounted display (HMD.

12. The system of claim 1, further comprising two access points, each access point comprising one of the multifrequency RF transmitters.

13. The system of claim 12, wherein one of the two access points is a wireless router.

14. The system of claim 1, wherein the mobile device further comprises one or more sensors adapted to provide the known heading and orientation of the mobile device.

15. The system of claim 1, wherein the spatial separation between the at least two mobile display antennae is five inches.

16. The system of claim 1, wherein the receiver circuit has an independent receiver channel for each of the at least two mobile display antennae.

17. The system of claim 1, wherein the receiver circuit has a receiver channel shared by the at least two mobile display antennae.

18. A method for tracking a mobile device in real time comprising the steps of:

determining heading and orientation of the mobile device;

transmitting, by first and second radio frequency (RF) transmitters disposed at known positions that are within a maximum unambiguous range of the mobile device, multifrequency RF signals;

conveying the known position and identification of each RF transmitter in the multifrequency RF signal transmitted by that RF transmitter;

receiving the multifrequency RF signals by two antennae operably coupled to the mobile device with a known spatial separation on the mobile device;

comparing phases of multiple frequencies of each multifrequency RF signal received by each of the two antennae;

determining phase differences between the compared phases;

calculating a distance from each RF transmitter to each of the two antennae based on the phase differences;

calculating a position of each of the two antennae based on the calculated distances, the known positions of the RF transmitters, the known spatial separation of the antennae on the display, and the orientation and heading of the mobile device; and

displaying images on a display of the mobile device from a viewpoint based upon the calculated positions of the two antennae.