Granted Patent B2

US 9,301,089 · App. 13/876,996 · Granted Mar 29, 2016

Abstract

Claims (34)

1. A method comprising:

receiving at each of at least three antenna elements of a positioning device a wireless signal having modulated thereon an identifier relating to a transmitting device;

obtaining complex signal parameters of a signal received at each of the at least three antenna elements;

determining a measure of a strength of the received wireless signal;

comparing the measure to a threshold associated with the identifier;

if the measure exceeds the threshold, processing the complex signal parameters to determine a bearing of the transmitting device from the positioning device; and

if the measure does not exceed the threshold, discarding the complex signal parameters without processing them to determine a bearing.

2. A method as claimed in claim 1 , comprising the positioning device comparing the measure to the threshold associated with the identifier, the positioning device transmitting a message comprising the complex signal parameters for remote processing to determine the bearing of the transmitting device from the positioning device if the measure exceeds the threshold, and the positioning device discarding the complex signal parameters without first transmitting them if the measure does not exceed the threshold.

3. A method as claimed in claim 1 , comprising storing a database of identifiers and one of corresponding thresholds or information from which thresholds can be derived.

4. A method as claimed in claim 3 , comprising updating the database using information received from one of an external device or a remote server.

5. A method as claimed in claim 3 , comprising:

storing a list of disallowed mobile devices;

determining if an identifier received from a transmitting device relates to a mobile device that is included in the list of disallowed mobile devices; and

in the event of a positive determination, discarding the complex signal parameters without processing them to determine a bearing.

6. Apparatus comprising:

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform:

obtaining complex signal parameters for a signal received at each of at least three antenna elements, the wireless signal having modulated thereon an identifier relating to a transmitting device;

determining a measure of a strength of the received wireless signal;

comparing the measure to a threshold associated with the identifier;

responsive to a determination that the measure exceeds the threshold, processing the complex signal parameters to determine a bearing of the transmitting device from the positioning device; and

responsive to a determination that the measure does not exceed the threshold, discarding the complex signal parameters without processing them to determine a bearing.

7. Apparatus as claimed in claim 6 , wherein the at least one memory and the computer program are further configured to, with the at least one processor, cause the apparatus to perform: comparing the measure to the threshold associated with the identifier; transmitting a message comprising the complex signal parameters for remote processing if the measure exceeds the threshold; and discarding the complex signal parameters without first transmitting them if the measure does not exceed the threshold.

8. Apparatus as claimed in claim 6 , comprising a memory storing a database of identifiers and one of corresponding thresholds or information from which thresholds can be derived.

9. Apparatus as claimed in claim 8 , wherein the at least one memory and the computer program are further configured to, with the at least one processor, cause the apparatus to perform updating the database using information received from a remote server.

10. Apparatus as claimed in claim 8 , wherein the memory stores a list of disallowed mobile devices, and the at least one memory and the computer program are further configured to, with the at least one processor, cause the apparatus to perform: determining if an identifier received from a transmitting device relates to a mobile device that is included in the list of disallowed mobile devices; and, in the event of a positive determination, discarding the complex signal parameters without processing them to determine a bearing.

11. Apparatus as claimed in claim 6 , wherein the measure of strength of the received wireless signal is signal power.

12. A non-transitory machine readable medium comprising computer code stored thereon that when executed by a processor causes an apparatus to perform a method comprising:

obtaining complex signal parameters of a wireless signal received at each of at least three antenna elements of a positioning device;

determining a measure of a strength of the received wireless signal;

comparing the measure to a threshold associated with an identifier modulated onto the received wireless signal;

if the measure exceeds the threshold, processing the complex signal parameters to determine a bearing of the transmitting device from the positioning device; and

if the measure does not exceed the threshold, discarding the complex signal parameters without processing them to determine a bearing.

Assignments (10)