# US 2014/0152505 A1 · Apparatus and method for estimating direction of radio frequency signal > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0152505 A1 - Document ID: US20140152505A1 - Status: Published application - Kind: A1 - Application number: 13/918,678 - Filed: 2013-06-14 - Published: 2014-06-05 - Earliest claimed: 2012-11-30 - Assignees: Electronics and Telecommunications Research Institute - Applicants: Electronics and Telecommunications Research Institute - Inventors: Jong-Kyu KIM; Hui-Rae CHO; Jin-Gak JANG; In-Ho HWANG; Chun-Soo KIM - Web page: https://patentgrep.com/patent/US20140152505A1 ## CPC - G01S 3/40: adjusting orientation of a single directivity characteristic to produce maximum or minimum signal, e.g. rotatable loop antenna or equivalent goniometer system - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract An apparatus and method for estimating the direction of an RF signal is provided. The apparatus includes an antenna for receiving an RF signal. An electronic compass is configured to, as a pointing direction of the antenna is varied, generate information about pointing directions and pointing angles corresponding to variations in the pointing direction of the antenna. A control unit determines RSSI values at respective, pointing angles of the antenna based on a received signal of the antenna and information of the electronic compass depending on the variations, extracts a maximum RSSI value from the RSSI values at respective pointing angles, and stores the maximum RSSI value and a pointing direction corresponding to the maximum RSSI value. A display unit displays the RSSI values at the respective pointing angles and a trajectory of the RSSI values at respective pointing angles under control of the control unit. ## Claims ### Claim 1 An apparatus for estimating a direction of a RF signal, comprising: an antenna for receiving an RF signal; an electronic compass for, as a pointing direction of the antenna is varied, generating information about pointing directions and pointing angles corresponding to variations in the pointing direction of the antenna; a control unit for determining RSSI values at respective pointing angles of the antenna based on a received signal of the antenna and information of the electronic compass depending on the variations in the pointing direction of the antenna, extracting a maximum RSSI value from the RSSI values at the respective pointing angles, and storing the maximum RSSI value and a pointing direction corresponding to the maximum RSSI value; and a display unit for displaying the RSSI values at the respective pointing angles and a trajectory of the RSSI values at the respective pointing angles under control of the control unit. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the display unit displays the RSSI values at the respective pointing angles in a form of one or more of numerals, a bar graph, and polar coordinates. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the display unit displays a pointing line indicating a pointing direction depending on movement of the antenna in a polar coordinate system. ### Claim 4 (depends on 1) The apparatus of claim 1, further comprising a mode setting unit for setting a start and an end of a mode in which an arrival direction of the RF signal is estimated, wherein the control unit is operated depending on settings by the mode setting unit. ### Claim 5 (depends on 4) The apparatus of claim 4, wherein the display unit is configured to, if the mode in which the arrival direction of the RF signal is estimated ends, display a trajectory of the RSSI values at the respective pointing angles obtained for a measurement time and a pointing line indicating a direction of the maximum RSSI value in a polar coordinate system. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the control unit is connected to a spectrum analyzer for receiving a received signal of the antenna through a cable and is configured to receive a plurality of RSSI values at each pointing angle from the spectrum analyzer, calculate an average of the RSSI values at the corresponding pointing angle, and determine the average to be an RSSI value at the corresponding pointing angle. ### Claim 7 (depends on 6) The apparatus of claim 6, wherein the cable comprises a cable body, an RF connector installed in one side of the cable body and configured to perform impedance matching with impedance of the antenna, and a data communication connector installed on one side of the cable body separately from the RF connector. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the antenna is implemented as a uni-directional antenna. ### Claim 9 An apparatus for estimating a direction of a RF signal, comprising: an antenna for receiving an RF signal; an electronic compass for, as a pointing direction of the antenna is varied, generating information about pointing directions and pointing angles corresponding to variations in the pointing direction of the antenna; a digital signal processing unit for receiving the RF signal from the antenna and calculating a RSSI value corresponding to the RF signal; a control unit for determining RSSI values at respective pointing angles of the antenna corresponding to the variations in the pointing direction of the antenna based on the RSSI value from the digital signal processing unit and information of the electronic compass, extracting a maximum RSSI value from the RSSI values at the respective pointing angles, and storing the maximum RSSI value and a pointing direction corresponding to the maximum RSSI value and a display unit for displaying the RSSI values at the respective pointing angles and a trajectory of the RSSI values at the respective pointing angles under control of the control unit. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the control unit receives a plurality of RSSI values at each pointing angle from the digital signal processing unit, calculates an average of the RSSI values at the corresponding pointing angle, and determines the calculated average to be an RSSI value at the corresponding pointing angle. ### Claim 11 (depends on 9) The apparatus of claim 9, wherein the display unit displays the RSSI values at the respective pointing angles in a form of one or more of numerals, a bar graph, and polar coordinate plot. ### Claim 12 (depends on 9) The apparatus of claim 9, wherein the display unit displays a pointing line indicating a pointing direction depending on movement of the antenna in a polar coordinate system. ### Claim 13 (depends on 9) The apparatus of claim 9, further comprising a mode setting unit for setting a start, and an end of a mode in which an arrival direction of the RF signal is estimated, wherein the control unit is operated depending on settings by the mode setting unit. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein the display unit is configured to, if the mode in which the arrival direction of the RF signal is estimated ends, display a trajectory of the RSSI values at the respective pointing angles obtained for a measurement time and a pointing line indicating a direction of the maximum RSSI value in a polar coordinate system. ### Claim 15 A method of estimating a direction of a RF signal, comprising: determining, by a control unit, RSSI values at respective pointing angles of an antenna, based on a received signal of the antenna and information of an electronic compass related to a pointing direction and a pointing angle of the antenna; extracting, by the control unit, a maximum RSSI value from the RSSI values at the respective pointing angles, and storing the maximum RSSI value and a pointing direction corresponding to the maximum RSSI value; and displaying, by a display unit, the RSSI values at the respective pointing angles and a trajectory of the RSSI values at the respective pointing angles. ### Claim 16 (depends on 15) The method of claim 15, wherein determining the RSSI values at the respective pointing angles of the antenna comprises: calculating an average of a plurality of RSSI values generated at each pointing angle of the antenna; and determining the calculated average to be an RSSI value at the corresponding pointing angle. ### Claim 17 (depends on 15) The method of claim 15, wherein displaying is configured to display the RSSI values at the respective pointing angles in a form of one or more of numerals, a bar graph, and polar coordinates. ### Claim 18 (depends on 15) The method of claim 15, wherein displaying is configured to display a pointing line indicating a pointing direction depending on movement of the antenna in a polar coordinate system. ### Claim 19 (depends on 15) The method or claim 15, wherein displaying is configured to display a trajectory of the RSSI values at the respective pointing angles obtained for a measurement time and a pointing line indicating a direction of the maximum RSSI value in a polar coordinate system.