System for verifying distance measurements

Patent metadata

Field	Value
Publication number	US-11150339-B2
Application number	US-201615777408-A
Country	US
Kind code	B2
Filing date	Nov 21, 2016
Priority date	Nov 23, 2015
Publication date	Oct 19, 2021
Grant date	Oct 19, 2021

Abstract

A first device ( 110 ) for distance measurement via wireless communication ( 130 ) uses a ranging protocol for determining a distance ( 140 ) to a second device ( 120 ) via a round trip time measurement, wherein first time data represents the round trip time and second time data represents a response time between receiving a request and sending a corresponding acknowledge. The second device receives the round trip time and determines the distance. The first device determines third time data by subtracting from the first time data a calculated travelling time of the messages between the first device and the second device based on the determined distance, and determines identifier data indicative of hardware and/or software present in the second device. The device then obtains, from a database based on the identifier data, a reference interval value, and verifies whether the determined distance is reliable by comparing the third time data to the reference interval value.

First claim

The invention claimed is:

1. An apparatus for measuring a distance via wireless communication between a first device and a second device, comprising:
a predetermined protocol for determining the distance between the first and the second device based on a round trip time measurement, wherein the first device sends a measurement message at a first time, the second device receives the measurement message at a second time, the second device transmits a measurement acknowledge at a third time, and the first device receives the measurement acknowledge at a fourth time;
a transceiver configured for transmitting and receiving messages; and
a processor configured for generating the messages to be transmitted and processing the received messages, wherein the processor is further configured to:
determine first time data representing a first interval between the first time and the fourth time;
determine second time data representing a second interval between the second time and the third time;
determine the distance by calculating a travelling time of the messages between the first device and the second device based on the first time data and the second time data;
determine third time data by subtracting the travelling time of the messages from the first time data;
determine identifier data indicative of hardware and/or software present in the second device;
obtain from a database, based on the identifier data, a reference interval value for the second device indicative of an interval between receiving the measurement message and transmitting the measurement acknowledge; and
verifying the distance by comparing the third time data and the reference interval value.

2. The apparatus as claimed in claim 1 , wherein the processor is further configured to derive the identifier data from a message of the predetermined protocol from the second device.

3. The apparatus as claimed in claim 1 wherein the processor is configured to update at least one reference interval value in the database based on measurement data of the second device.

4. The apparatus as claimed in claim 1 , wherein the predetermined protocol comprises a reference message, and the processor is configured for obtaining the reference interval value based on the reference message received from the second device.

5. The apparatus as claimed in claim 4 , wherein the processor is configured for receiving the reference message before sending the measurement message.

6. The apparatus as claimed in claim 1 , wherein the processor is configured for obtaining respective measurement data from multiple respective distance measurements via the predetermined protocol and detecting differences between the respective measurement data.

7. The apparatus as claimed in claim 6 , wherein the processor is configured to:
execute said multiple respective distance measurements between the first device and the second device and to determine differences between the respective second time data of a first respective measurement data and the respective second time data of subsequent respective measurement data;
execute said multiple respective distance measurements as a sequence of distance measurements between the first device and the second device and to determine a sequence interval between measurements in the sequence, and compare the sequence interval to a reference sequence interval from a database; or
obtain at least one further measurement data from a distance measurement between a further device and the second device, and to obtain the reference interval value from the further measurement data.

8. The apparatus as claimed in claim 6 , wherein the processor is configured to:
obtain a reverse measurement data from a reverse execution of the predetermined protocol between the second device and the first device, the reverse measurement data comprising reverse first time data;
determine fourth time data by subtracting from the reverse first time data the third time data and a travelling time of the messages between the first device and the second device based on the determined distance; and
determine that the distance is unreliable if the fourth time data exceeds a predetermined error margin.

9. The apparatus as claimed in claim 6 , wherein the processor is configured to:
obtain at least one further measurement data from a distance measurement between at least one further device and the second device and derive at least one further determined distance from the further measurement data;
obtain actual position data of the least one further device relative to the first device; and
verify the determined distance by determining whether an estimated position of the second device relative to the first device is derivable based on the determined distance and the at least one further determined distance; or
verify the determined distance by determining whether an estimated position of the second device relative to the first device is in accordance with a predetermined floor plan around the first device.

10. The apparatus as claimed in claim 1 , wherein the processor is configured to:
determine at least one signal strength of at least one message received during the predetermined protocol; and
verify the determined distance by comparing the signal strength to an expected signal strength at the determined distance.

11. The apparatus as claimed in claim 1 , wherein the processor is further configured to at least one of:
require executing a different security protocol with the second device;
request a further distance measurement using a different ranging protocol and/or a different type of wireless communication;
deny or restrict access to at least some data and/or to at least one application in the first device.

12. A method for measuring a distance via wireless communication between a first device and a second device, comprising:
a processor providing a predetermined protocol for determining the distance between the first and the second device based on a round trip time measurement, wherein the first device sends a measurement message at a first time, the second device receives the measurement message at a second time, the second device transmits a measurement acknowledge at a third time, and the first device receives the measurement acknowledge at a fourth time;
the processor determining first time data representing a first interval between the first time and the fourth time;
the processor determining second time data representing a second interval between the second time and the third time;
the processor determining the distance by calculating a travelling time of the messages between the first device and the second device based on the first time data and the second time data; and
the processor determining third time data by subtracting the travelling time of the messages from the first time data;
the processor determining identifier data indicative of hardware and/or software present in the second device;
obtaining from a database, based on the identifier data, a reference interval value for the second device indicative of an interval between receiving the measurement message and transmitting the measurement acknowledge; and
verifying the distance by comparing the third time data and the reference interval value.

13. The apparatus as claimed in claim 1 , wherein after comparing the third time data and the reference interval value, if a comparison deviates by more than a predetermined error margin, then the determined distance is considered as not reliable.

14. A non-transitory computer-readable medium having one or more executable instructions stored thereon, which when executed by

Assignees

• Koninklijke Philips Nv

Inventors

• Dees Walter
• Van De Laar Franciscus Antonius Maria

Classifications

• G01S13/765 Primary

  with exchange of information between interrogator and responder · CPC title

• G01S7/40

  Means for monitoring or calibrating · CPC title

• G01S7/36

  Means for anti-jamming {, e.g. ECCM, i.e. electronic counter-counter measures} · CPC title

• G01S13/74

  Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems · CPC title