Method of Determining the Position of a Transponder in Relation to a Communicator

• US 20100001836A1
• Filed: 12/06/2005
• Published: 01/07/2010
• Est. Priority Date: 12/30/2004
• Status: Abandoned Application

• Current Assignee: Tagmaster AB
• Original Assignee: Tagmaster AB
• Inventors: Willgert, Mikael
• Application Number:
  US11/794,477
• Publication Number:
  US 20100001836A1
• Time in Patent Office: Days
• US Class Current: 340/10.1
• CPC Class Codes: G01S 13/74 Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems

Abstract

A method of determining the position of a transponder in relation to a communicator, wherein the transponder (9) can be read by a communicator (11) which is adapted to send an inquiry signal to the transponder, wherein the transponder (9) is adapted to answer the inquiry signal and therewith transfer information from a memory in the transponder and wherein the communicator (11) is connected to a principal data system (16) and is adapted to receive the information. The method is characterized by connecting the communicator (11) to an envelope detector (15) which is caused to detect the envelope of the signal received from the transponder (9); and by determining the relative position between the transponder (9) and the communicator (11) from the envelope.

Claims

1-4. -4. (canceled)

5. A method of determining the position of a transponder in relation to a communicator, wherein the transponder (9) can be read by means of a communicator (11) which is adapted to send an inquiry signal to the transponder, wherein the transponder (9) is adapted to answer the inquiry signal and therewith transfer information from a memory in the transponder and wherein the communicator (11) is connected to a principal data system (16) and is adapted to receive said information, where the communicator (11) is arranged at a vehicle and where the transponder (9) is arranged at a way for, or a path for, transportation for the vehicle and wherein the communicator is connected to an envelope detector (15), which is caused to detect the envelope of the signal received by the transponder (9) and wherein the method is characterized by causing the relative position between the transponder (9) and the communicator (11) to be determined from said envelope with an accuracy of less than +/−

10 cm by determining the maximum of the envelope or a value above a predetermined threshold value for the envelope or a function of the envelope, and by determining the relative position between the transponder (9) and the communicator (11) at said pre-determined value of said envelope.

6. A method according to claim 5, characterized by determining a time point (t1) for a first threshold value as the envelope rises and the time point (t2) of a second threshold as the envelope falls after having passed said maximum;

and by calculating that the time point™

of said maximum will have occurred midway between said two time points (t1, t2).

7. A method according to claim 5, wherein in the event of a delay from the time(tm) of the envelope maximum is detected and a signal to this effect reaches the principal data system, the principal data system (16) is caused to subtract this delay when calculating the physical position when said maximum is measured.

8. A method according to claim 6, wherein in the event of a delay from the time(tm) of the envelope maximum is detected and a signal to this effect reaches the principal data system, the principal data system (16) is caused to subtract this delay when calculating the physical position when said maximum is measured.