Position acquisition

• US 20030129993A1
• Filed: 10/28/2002
• Published: 07/10/2003
• Est. Priority Date: 02/02/2000
• Status: Active Grant

• Current Assignee: Nokia Corporation
• Original Assignee: Nokia Corporation
• Inventors: Overy, Michael, Lobo, Natividade
• Granted Patent: US 7,107,065 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01C 21/14 by recording the course traversed by the object G01C21/16 takes precedence
• CPC Class Codes: G01S 13/876 Combination of several spaced transponders or reflectors of known location for determining the position of a receiver G01S13/874 takes precedence
• CPC Class Codes: G01S 5/0244 Accuracy or reliability of position solution or of measurements contributing thereto
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• CPC Class Codes: G01S 7/40 Means for monitoring or calibrating
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A first transceiver (4, 30) can position itself by forming an ad hoc network (20) of transceivers which assist the first transceiver in acquiring its position. A dedicated infrastructure such as GPS satellites is not required. The first transceiver (4, 30), once it has acquired its position, can be involved in a network (20) by another transceiver (32, 34, 36, 38, 40) to assist in the positioning of that transceiver. The acquisition of the position may involve factors such as the trustworthiness of the transceivers in the network and/or the positions of transceivers with which the first transceiver cannot directly communicate.

Claims

1. A radio transceiver for use in a variable arrangement comprising a plurality of radio transceivers, operable:

to form a wireless network with proximal ones of said plurality of transceivers and to control that network;

to calculate, when controlling a network, its position by processing position-related messages received from the proximal transceivers in the network;

to be included in a network controlled by a proximal one of said plurality of radio transceivers; and

to transmit, when included in a network controlled by said proximal controlling radio transceiver, to the proximal controlling radio transceiver at least one position-related message.

2. A radio transceiver as claimed in claim 1, wherein each position-related message has a predetermined format and a content dependent upon the position of the radio transceiver from which it is transmitted, comprising:

a memory;

receiver circuitry operable when the radio transceiver controls the network to receive a position related message from each of the proximal transceivers included in the network;

processing means operable to determine, from the received position-related messages, location data identifying the position of the radio transceiver and store the determined location data in the memory; and

transmitter circuitry operable, when the radio transceiver is included in a network, to transmit to the proximal controlling radio transceiver at least one position-related message having said predetermined format and a content dependent upon the radio transceiver'"'"'s determined location data stored in the memory.

3. A radio transceiver as claimed in claim 1 or 2 wherein each position-related message comprises an indication of position of the radio transceiver from which it is transmitted.

4. A radio transceiver as claimed in claim 3 wherein each position-related message additionally comprises an indication of error in position.

5. A radio transceiver as claimed in any preceding claim arranged to store an indication of trustworthiness related to the probable accuracy of the position-related messages it transmits when included in a network.

6. A radio transceiver as claimed in claim 5 wherein said indication of trustworthiness identifies the radio transceiver as portable.

7. A radio transceiver as claimed in claim 5 wherein said indication of trustworthiness identifies the radio transceiver as a reference type, having a reliable position.

8. A radio transceiver as claimed in any one of claims 5 to 7, wherein the position-related message transmitted by the transceiver includes said indication of trustworthiness.

9. A radio transceiver as claimed in any preceding claim arranged to store identification data uniquely identifying the radio transceiver, wherein position-related messages transmitted by the transceiver include said identification data.

10. A radio transceiver as claimed in any preceding claim wherein the position-related message includes an indication of the power at which the position-related message is transmitted or an indication of the range of transmission for the transceiver.

11. A radio transceiver as claimed in any preceding claim wherein the calculation of position from the received position-related messages comprises a first-order calculation based upon the positions of the proximal radio transceivers, each being radio transceivers which can directly communicate by transmission and reception with the radio transceiver.

12. A radio transceiver as claimed in any preceding claim wherein said calculation of position from the received position-related messages comprises a second-order calculation including calculations based upon the positions of non-proximal ones of said plurality of radio transceivers each of which can directly communicate by transmission and reception with at least one of the proximal transceivers but cannot directly communicate with the radio transceiver.

13. A radio transceiver as claimed in any preceding claim wherein said calculation of position from the received position-related messages includes calculations based upon the positions and the maximum communication range of each of the first plurality of proximal transceivers.

14. A radio transceiver as claimed in any one of claims 1 to 12 wherein said calculation of position from the received position-related messages includes calculations based upon the positions and estimated distance to the radio transceiver for each one of the first plurality of proximal transceivers.

15. A radio transceiver as claimed in claim 14 further comprising power detection circuitry for detecting the power of a received signal and estimation means for estimating from the detected power of a received signal the distance to the one of the first plurality of proximal transceivers which transmitted the signal.

16. A radio transceiver as claimed in any one of claims 1 to 12 wherein said calculation of position from the received position-related messages includes the convolution of the probability density functions, representing the position of the proximal transceivers, included in received position-related messages with probability density functions representing the likelihood that a transmission from the proximal transmitting transceivers will be successfully received at the radio transceiver.

17. A radio transceiver as claimed in any preceding claim wherein said calculation of position from the received position-related messages comprises calculations dependent upon the trustworthiness of at least one of the proximal transceivers.

18. A radio transceiver as claimed in any preceding claim wherein said calculation of position from the received position-related messages comprises weighted calculations dependent upon the trustworthiness of the proximal transceivers.

19. A radio transceiver as claimed in any preceding claim arranged to transmit a request to each of the proximal transceivers

20. A radio transceiver as claimed in any preceding claim arranged, in response to a received request, to transmit said position-related message to the transceiver which made the request.

21. A radio transceiver as claimed in any preceding claim further comprising control means for controlling the transceiver to act as a Master and form a wireless network with said proximal transceivers as Slaves.

22. A radio transceiver as claimed in any preceding claim further comprising control means for controlling the transceiver to act as a Slave included in a wireless network.

23. A radio transceiver as claimed in any preceding claim operating in accordance with the Bluetooth wireless protocol.

24. A radio transceiver as claimed in any preceding claim comprising control means for causing the transceiver to enter a position acquisition mode in which:

the transceiver transmits requests to each of the first plurality of proximal transceivers;

the transceiver receives in response a position-related message from each of the first plurality of proximal transceivers; and

the transceiver processes the position-related messages to estimate its location.

25. A radio transceiver as claimed in any preceding claim arranged to transmit to each of the first plurality of transceivers, after the calculation of its position, to inform them of its newly calculated position.

26. A radio transceiver as claimed in claim 25 wherein said transmission to each of the first plurality of transceivers to inform them of the newly calculated position is conditional upon the newly calculated position differing substantially from a previously calculated position.

27. A chipset for a radio transceiver as claimed in any preceding claim wherein the chipset provides the processing means operable to determine location data identifying the location of the radio, and control means for controlling the transmitter circuitry to transmit a message or messages dependent upon said location data.

28. A radio transceiver substantially as hereinbefore described with reference to the accompanying Figures and/or as shown in the Figures.

29. An arrangement of transceivers substantially as hereinbefore described with reference to the accompanying Figures and/or as shown in the Figures.

30. A method by which a first radio transceiver that has not acquired its position can acquire its position by the formation of an ad hoc radio communications network with a plurality of proximal radio transceivers which have already acquired their position and which assist the radio transceiver in its position acquisition, wherein the first radio receiver, after having acquired its position, is thereby able to assist, as part of an ad hoc radio communications network, a second radio transceiver that has not acquired its position to acquire its position, comprising the steps of:

the radio transceiver which has not acquired its position forms a wireless network;

the radio transceivers included in the network that have acquired their positions transmit position related messages to the radio transceiver which has not acquired its position;

the radio transceiver which is acquiring its position, receives the transmitted position-related messages and acquires its position by calculation from the received position-related messages.

31. An arrangement comprising a plurality of radio transceivers including at least one movable radio transceiver wherein each of said plurality of radio transceivers is operable:

to form a wireless network with proximal ones of said plurality of transceivers and to control that network;

to calculate, when controlling a network, its position by processing position-related messages received from the proximal transceivers in the network;

to be included in a network controlled by a proximal one of said plurality of radio transceivers; and

to transmit, when included in a network controlled by said proximal controlling radio transceiver, to the proximal controlling radio transceiver at least one position-related message.

32. A radio transceiver for use in a variable arrangement comprising a plurality of radio transceivers including first order transceivers with which the transceiver can communicate directly and second-order transceivers with which the transceiver cannot communicate directly but can communicate with indirectly via a first order transceiver, arranged to determine its position by calculations which take account of where the transceiver is located because it can communicate directly with first order transceivers and which take account of where the transceiver is not located because it cannot communicate directly with the second-order transceivers.

33. A method by which a first radio transceiver that has not acquired its position can acquire its position from a plurality of radio transceivers including first order transceivers with which the transceiver can communicate directly and second-order transceivers with which the transceiver cannot communicate directly but can communicate with indirectly via a first order transceiver, comprising the steps of:

each of the first plurality of first order transceivers transmits its position;

at least one first order transceiver transmits the position of at least one second-order transceiver;

the first transceiver receives said transmitted positions and positions the first order transceiver and the at least one second order transceiver; and

the first transceiver acquires its position by calculations which take account of where the transceiver is located because it can communicate directly with positioned first order transceivers and which take account of where the transceiver is not located because it cannot communicate directly with the at least one positioned second-order transceiver.

34. A radio transceiver for use in an arrangement comprising a plurality of radio transceivers including first order transceivers with which the transceiver can communicate directly to acquire its position, arranged to

receive positions transmitted from the first order transceivers, wherein each first order transceiver transmits a position representing its location;

receive trust indications transmitted from at least one of the first order transceivers, wherein the trust indication transmitted by a first order transceiver represents the trustworthiness of the transmitting first-order transceiver; and

acquire its position by calculations which take account of the received positions and the received trust indications.

35. A method by which a first radio transceiver that has not acquired its position can acquire its position by communicating directly with a plurality of transceivers, comprising the steps of:

each of the first plurality of transceivers transmits its position;

at least one of the plurality of transceivers transmits a trust indication representing the trustworthiness of the at least one transceiver;

the first transceiver receives the plurality of transmitted positions and the at least one transmitted trust indication; and

the first transceiver acquires its position by calculations which take account of the received plurality of positions and the at least one received trust indication.

36. A receiver for calculating its position according to a first transmitter, having a processor arranged to convolve:

(i) the probability density function representing the position of the first transmitter, sent by the first transmitter to the receiver;

with

(ii) the probability density function representing the likelihood that a transmission from the first transmitter will be successfully received at the receiver.

37. A receiver as claimed in claim 36 for calculating its position according to a second transmitter, having a processor arranged to convolve:

(i) the probability density function representing the position of the second transmitter, sent by the second transmitter to the receiver;

with

(ii) the probability density function representing the likelihood that a transmission from the second transmitter will be successfully received at the receiver.

38. A receiver as claimed in claim 36 or 37 wherein the probability density function representing the likelihood that a transmission from the first transmitter will be successfully received at the receiver is an approximation which simplifies processing.

39. A receiver as claimed in claim 37 or 38, wherein the probability density function representing the likelihood that a transmission from the first transmitter will be successfully received at the receiver is the same as the probability density function representing the likelihood that a transmission from the second transmitter will be successfully received at the receiver.

40. A receiver as claimed in claim 36 for calculating its position according to a plurality of transmitters, having a processor arranged to calculate a probability density function for each of said plurality of transmitters by the convolution of

(i) the probability density function representing the position of one of the plurality of said transmitters, sent by said one transmitter to the receiver;

with

(ii) the probability density function representing the likelihood that a transmission from said one transmitting receiver will be successfully received at the receiver

and arranged to combine the resultant plurality of probability density functions.

41. A receiver as claimed in claim 40 wherein the combination of the resultant probability density functions involves pair-wise combination of probability density functions.

42. A receiver as claimed in claim 41 wherein the pair-wise combination involves the multiplication of one probability density function with another.

43. A receiver as claimed in claim 40 wherein the pair-wise combination involves the addition of one probability density function with another.

44. A receiver as claimed in claim 42 or 43, wherein the combination is a weighted combination.

45. A receiver as claimed in claim 44 wherein the weighted combination increases the contribution made from probability density functions derived from trusted transmitters.

46. A method of calculating the position of a receiver by communication with a plurality of transmitters comprising the steps of, for each of said plurality of transmitters, convolving:

(i) the probability density function representing the position of a transmitter, sent by the transmitter to the receiver;

with

(ii) the probability density function representing the likelihood that a transmission from the transmitter will be successfully received at the receiver

and combining the plurality of convolution products.

47. A method as claimed in claim 48 wherein the receiver is the Master transceiver in an ad-hoc network of Bluetooth transceivers and the plurality of transmitters are Slave transceivers in that Bluetooth network.