Local Positioning System and Method of Estimating Position a Mobile Wireless Unit in a Localised Area

• US 20080214203A1
• Filed: 06/16/2006
• Published: 09/04/2008
• Est. Priority Date: 06/17/2005
• Status: Active Grant

• Current Assignee: Fondazione Torino Wireless, Istituto Superiore Mario Boella Sulle Tecnologie Dell'Informazione e Delle Telecomunicazioni
• Original Assignee: Fondazione Torino Wireless, Instituto Superiore Mario Boella Sulle Tecnologie Del'Informazione E Delle Telecomunicati
• Inventors: Malnati, Giovanni, Forno, Fabio, Ferrari, Aleck, Portelli, Giuseppe, Badella, Monica, Di Gangi, Michele, Tessitore, Luca, Prato, Roberto, Valera, Loris, Titli, Andrea Pietro, Carlevato, Andrea
• Granted Patent: US 8,145,235 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location

Abstract

A local positioning system comprises a plurality of sensor elements that may communicate with mobile units in a wireless fashion. The responsiveness of the mobile units is measured by yes/no answers and averaged so as to provide a measure of the distance of a mobile unit to a specified sensor element. Based on this measure and the known positions of the sensor element, the position of the mobile unit is estimated, for instance by a model of ideal springs.

Claims

1-37. -37. (canceled)

38. A local positioning system comprising:

a plurality of sensor elements, each of which being configured to be located at a defined position within a confined area and configured to wirelessly transmit a sequence of communication signals for a number of wireless mobile units within said area, to identify acknowledge signals in response to at least some of said communication signals of said sequence from each of said mobile units, said plurality of sensor elements providing a plurality of digital values for each pair of said wireless mobile units and said sensor elements, on the basis of the result of said identification of said acknowledge signals;

one or more averaging units configured to receive said plurality of digital values for each sequence and generate averaged values of said plurality of digital values for each of the plurality of sensor elements; and

a control unit configured to connect to each of said sensor elements and said one or more averaging units and configured to receive said averaged values from said one or more averaging units, said control unit being further configured to estimate a position of said mobile units on the basis of said averaged values and said defined positions of the plurality of sensor elements.

39. The local positioning system of claim 38, wherein said sensor elements are further configured to transmit said communication signals of each sequence at different transmit power levels.

40. The local positioning system of claim 38, comprising means for providing said plurality of digital values in the form of sensor signals including an identification of the specific sensor element that generated said digital value.

41. The local positioning system of claim 40, wherein said acknowledge signals include an identification of the corresponding mobile unit, and said plurality of digital values include said identification.

42. The local positioning system of claim 40, wherein at least some of said sensor elements are configured to transmit said sensor signals to said control unit in a wireless manner.

43. The local positioning system of claim 38, wherein at least some of said sensor elements are connected to said control unit via a cable connection.

44. The local positioning system of claim 38, wherein said sensor elements are configured to provide said plurality of digital values as binary values.

45. The local positioning system of claim 38, wherein said one or more averaging units comprise a scalable averaging section for each sensor element configured to provide said averaged value so as to be designated to a respective sensor element and a mobile unit.

46. The local positioning system of claim 38, wherein said one or more averaging units comprise means for averaging said plurality of digital values by digital low pass filtering.

47. The local positioning system of claim 45, wherein each of the averaging sections is included in its associated sensor element.

48. The local positioning system of claim 38, wherein said one or more averaging units are included in said control unit.

49. The local positioning system of claim 38, wherein said control unit comprises an estimation section for estimating said position, said estimating section having incorporated a model based on a linear relationship of a distance of said mobile unit from a specific sensor element and said averaged value associated with said specific sensor element.

50. The local positioning system of claim 38, wherein said control unit is further configured to estimate the position of at least one further mobile unit within said confined area while preserving the estimated position of said mobile unit.

51. The local positioning system of claim 38, further comprising an interface for providing said estimated position to a platform connectable to said interface.

52. An apparatus for use in a local positioning system including a plurality of sensor elements, each being configured to be located at a defined position within a confined area and configured to wirelessly transmit a sequence of communication signals for a number of wireless mobile units within said area to identify acknowledge signals in response to at least some of said communication signals of said sequence from each of said mobile units, said plurality of sensor elements providing a plurality of digital values for each pair of said wireless mobile units and said sensor elements, on the basis of the result of said identification of said acknowledge signals, the apparatus comprising:

one or more averaging units configured to receive said plurality of digital values for each sequence and generate averaged values of said plurality of digital values for each of the plurality of sensor elements; and

a control unit configured to;

connect to each of said sensor elements and said one or more averaging units;

receive said averaged values from said one or more averaging units; and

estimate a position of said mobile units on the basis of said averaged values and said defined positions of the plurality of sensor elements.

53. A service system comprising:

(i) a local positioning system including;

a plurality of sensor elements, each of which being configured to be located at a defined position within a confined area and configured to wirelessly transmit a sequence of communication signals for a number of wireless mobile units within said area, to identify acknowledge signals in response to at least some of said communication signals of said sequence from each of said mobile units, said plurality of sensor elements providing a plurality of digital values for each pair of said wireless mobile units and said sensor elements, on the basis of the result of said identification of said acknowledge signals;

one or more averaging units configured to receive said plurality of digital values for each sequence and generate averaged values of said plurality of digital values for each of the plurality of sensor elements; and

a control unit configured to connect to each of said sensor elements and said one or more averaging units and configured to receive said averaged values from said one or more averaging units, said control unit being further configured to estimate a position of said mobile units on the basis of said averaged values and said defined positions of the plurality of sensor elements; and

(ii) a platform configured to connect to said local positioning system so as to receive data regarding the position of said mobile unit, said platform being configured to run one or more application routines for providing position sensitive services on the basis of said data.

54. The service system of claim 53, wherein said service system is designed for a location-based indoor environment.

55. The service system of claim 53, wherein said data indicate entering and/or exiting of said confined area by said mobile unit.

56. The service system of claim 53, further comprising one or more indication units for indicating service information produced by said one or more applications.

57. The service system of claim 56, wherein said one or more indication units are configured to provide said service information in a localized manner.

58. The service system of claim 57, wherein said one or more indication units comprise a communication unit configured for wireless data transfer to said mobile unit.

59. A method of estimating a position of a wireless mobile unit, the method comprising:

transmitting, from each of a plurality of defined fixed transmit positions arranged within a confined area, a respective sequence of communication signals;

evaluating a responsiveness of said wireless mobile unit to each sequence of communication signals by a plurality of digital values for at least some communication signals in each sequence;

averaging digital values associated with a respective one of said sequences to generate an averaged value for each sequence of communication signals; and

determining position data for said wireless mobile unit on the basis of said averaged values and said defined transmit positions.

60. The method of claim 59, wherein at least some of the communication signals in each sequence are transmitted with different transmit power.

61. The method of claim 59, wherein said digital value is a binary value indicating whether a respective communication signal is received by said mobile unit or not.

62. The method of claim 59, wherein averaging digital values for a respective sequence is performed remotely with respect to the defined position from which said sequence is transmitted.

63. The method of claim 62, further comprising transmitting said digital values for said respective sequence to a remote control unit.

64. The method of claim 63, wherein said digital values are transmitted via a wireless transmission channel.

65. The method of claim 62, wherein digital values of at least one sequence are transmitted via a cable transmission channel to a remote control unit.

66. The method of claim 59, wherein determining said position data comprises considering each averaged value of a respective sequence associated with a respective transmit position as a measure of a distance of said mobile unit from said respective transmit position, obtaining said distance for each transmit position on the basis of the respective averaged values and estimating a position of said mobile unit on the basis of said distances.

67. The method of claim 66, wherein determining said position data is performed on the basis of a model of ideal springs connecting said mobile unit with each of said transmit positions.

68. The method of claim 59, further comprising providing said position data to an interface.

69. The method of claim 68, further comprising supplying said position data to a location based service.

70. The method of claim 59, further comprising determining position data for a plurality of mobile units within said confined area within a predefined time period.

71. The method of claim 59, further comprising determining a desired spatial resolution for said mobile unit within said confined area, selecting a number and position or said defined transmit positions on the basis

of said determined spatial resolution and positioning at least one position sensor at each of said plurality of transmit positions.

72. The method of claim 71, wherein said desired spatial resolution is less than approximately 10 meters.

73. The method of claim 59, wherein said communication signal is compatible with an established protocol for wireless data communication.

74. A method of providing a location based service, the method comprising:

transmitting, from each of a plurality of defined fixed transmit positions arranged within a confined area, a respective sequence of communication signals;

evaluating a responsiveness of said wireless mobile unit to each sequence of communication signals by a plurality of digital values for at least some communication signals in each sequence;

averaging digital values associated with a respective one of said sequences to generate an averaged value for each sequence of communication signals;

determining position data for said wireless mobile unit on the basis of said averaged values and said defined transmit positions;

receiving said position data; and

providing information based on said position data.

75. The method of claim 74, wherein said positional data indicate entering of said mobile unit into said confined area.

76. The method of claim 74, wherein said information is further related to a status of said confined area.

77. The method of claim 74, further comprising using said position data for establishing an interaction of said mobile unit with one of or more of a plurality of sources, wherein said one or more sources are selected so as to be located in the neighborhood of said mobile unit.