Device for localizing a transmitter unit

• US 6,414,633 B1
• Filed: 05/09/2001
• Issued: 07/02/2002
• Est. Priority Date: 11/09/1998
• Status: Expired due to Fees

• Current Assignee: Micro Positioning AB
• Original Assignee: Micro Positioning AB
• Inventors: Delalat, Hamid
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US09/831,298
• Time in Patent Office: 419 Days
• Field of Search: 342/442, 342/450, 342/457, 342/463, 342/464
• US Class Current: 342/442
• CPC Class Codes: G01S 13/825 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 3/48 the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured
• CPC Class Codes: G01S 5/04 Position of source determined by a plurality of spaced direction-finders
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial

Abstract

A device for localizing a transmitter unit. The device includes a base unit and at least one transmitter. The transmitter unit includes an attachment operable to attach the transmitter unit to an object. A transmitter member is arranged to transmit a signal having a determined frequency content. The base unit is arranged to receive the signal from the transmitter member and includes at least two antennas that are positioned a relatively small distance from each other and are arranged to sense the signal. The base unit includes a processing member that is arranged to calculate at least the direction to the transmitter unit utilizing the signal sensed by the antennas. The transmitter unit includes a receiver member. The base unit includes a transmitter member. The transmitter member of the base unit and the receiver member of the transmitter unit are arranged to communicate with a protocol.

Claims

1. A device for localising a transmitter unit (2), comprising a base unit (1) and at least one such transmitter unit (2), wherein said transmitter unit (2) comprises means (4), which enable attachment of the transmitter unit (2) to an object (3), and a transmitter member (6), which is arranged to transmit a signal having a determined frequency content, wherein the base unit (1) is arranged to receive said signal and comprises at least two antennas (7), which are positioned on a relatively small distance (a) from each other and each arranged to sense such signal, and wherein the base unit (1) comprises a processing member (9), which is arranged to calculate at least the direction to said transmitter unit (2) by means of the signal sensed by the antennas (7), characterised in that said transmitter unit (2) comprises a receiver member (17), the base unit (1) comprises a transmitter member (18), and the transmitter member (18) of the base unit (1) and the receiver member (17) of the transmitter unit (2) are arranged to communicate by means of a protocol.

2. A device according to claim 1, wherein said signal is sensed by a phase displacement between the different antennas (7), due to said distance between the antennas (7), characterised in that the processing member (9) is arranged to measure this phase displacement and to calculate said direction by means of the phase displacement measured.

3. A device according to claim 1, characterised in that the base unit (1) is arranged to transmit a signal to said transmitter unit (2) which is arranged to transmit said signal back to the base unit (1), wherein the processing member (9) is arranged to measure the time period from the transmission of the signal to the transmitter unit (2) until the reception of the signal by the base unit (1), and by means of the time period measured determine the distance to said transmitter unit (2).

4. A device according to claim 3, characterised in that the processing member (9) is arranged to calculate the position of said transmitter unit (2) by means of the determined distance and the determined direction.

5. A device according to claim 4, characterised in that the base unit (1) is arranged to activate the transmitter member (6) of the transmitter unit (2) by a transmission permission which is transferred to the transmitter unit via the transmitter member (18) of the base unit and the receiver member (17) of the transmitter unit.

6. A device according to claim 5, characterised in that the transmitter member (18) of the base unit (1) and the receiver member (17) of the transmitter unit (2) are arranged to transfer said transmission permission by means of a CDMA/CD protocol.

7. A device according to claim 1, characterised in that each of said antennas (7) comprises an essentially straight antenna (9).

8. A device according to claim 7, characterised in that the antennas (7) extend in essentially the same direction.

9. A device according to claim 1, characterised in that the distance (a) between two adjacent antennas are less than one meter.

10. A device according to claim 1, characterised in that the base unit (1) is mobile.

11. A device according to claim 1, characterised in that the device comprises at least two transmitter units (2) and that each transmitter unit is arranged to transmit a signal according to an identification protocol and that the base unit (1) is arranged to identify the transmitter unit (2) in question by means of said identification protocol.

12. A device according to claim 1, characterised by a display member (13) which is arranged to display information about said position of said transmitter unit (2) to a user.

13. A device according to claim 12, characterised in that the display member (13) is an integrated part of the base unit (1) or formed by a unit, such as a computer, connected to the base unit (1).