Apparatus and Method for Computing Location of a Moving Beacon Using Received Signal Strength and Multi-Frequencies

• US 20080316104A1
• Filed: 12/08/2006
• Published: 12/25/2008
• Est. Priority Date: 12/08/2005
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Chae, Jong-Suk, Pyo, Cheol-Sig, Seong, Nak-Seon, Lim, Choon-Sik
• Granted Patent: US 8,040,280 B2
• Time in Patent Office: Days
• US Class Current: 342/442
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308

Abstract

Provided is an apparatus and method for computing the location of a radio beacon by using received signal strength (RSS) and multiple frequencies. The apparatus and method of the present invention computes the location of a radio beacon without limitation in distance by using multiple frequencies and received signal strength to resolve the problem of phase ambiguity. A radio beacon location computing system includes a plurality of base stations configured to receive signals of multiple frequencies transmitted from the radio beacon, and detect and output phase differences and received signal strength; and a location computing server configured to receive the phase differences and the received signal strength outputted from the respective base stations, acquire calculation distances based on the phase differences, remove phase ambiguity from the calculation distances based on the received signal strength, and compute the location of the radio beacon.

Claims

1. A method for computing a location of a radio beacon by using received signal strength (RSS) and multiple frequencies, comprising the steps of:

a) receiving signals of multiple frequencies in a plurality of base stations from the radio beacon and acquiring signal strength (s1, . . . , sn) of the received signals;

b) receiving phase differences Δ

Φ

1, Δ

Φ

2 and Δ

Φ

3 of the multi-frequency signals from the base stations;

c) acquiring calculation distances (R1, . . . , Rn) based on the phase differences;

d) removing phase ambiguity from the calculation distances by using the received signal strength; and

e) determining the location of the radio beacon based on the calculation distances deprived of the phase ambiguity.

2. The method as recited in claim 1, wherein the step d) includes the steps of:

d1) calculating distances (d1, . . . , dn) to the radio beacon based on the received signal strength; and

d2) removing the phase ambiguity from the calculation distances by using the distances.

3. The method as recited in claim 2, wherein a solution close to the distance is selected as a calculation distance among redundant solutions of the calculation distance produced due to the phase ambiguity in the step d2).

4. The method as recited in claim 1, wherein an intersection point where a plurality of circles each drawn by taking each base station at a center and taking the calculation distance deprived of the phase ambiguity as a radius meet is determined as the location of the radio beacon in the step e).

5. A system for computing a location of a radio beacon by using received signal strength and multiple frequencies, comprising:

a plurality of base stations configured to receive signals of multiple frequencies transmitted from the radio beacon, and detect and output phase differences and received signal strength; and

a location computing server configured to receive the phase differences and the received signal strength outputted from the respective base stations, acquire calculation distances based on the phase differences, remove phase ambiguity from the calculation distances based on the received signal strength, and compute the location of the radio beacon.

6. The system as recited in claim 5, wherein the base stations include:

a receiver configured to receive signals transmitted from the radio beacon and output the received signals;

a phase difference calculator configured to calculate and output phase difference of the received signals; and

a received signal strength detector configured to detect and output the signal strength of the received signals.

7. The system as recited in claim 5, wherein the location computing server calculates distance to the radio beacon based on the received signal strength, and removes the phase ambiguity from the calculation distance by using the distance.