Method and system for identifying and finding a range of an object

Abstract

A method for identifying and ranging a wireless device, comprising: transmitting an original radar signal from a detecting system; in response to the original radar signal, receiving a modulated radar signal at the detecting system, the modulated radar signal being backscattered from an antenna of the wireless device and containing information pertaining to the wireless device, and the modulated radar signal being a frequency offset version of the original radar signal; and, using a processor at the detecting system, determining an identity and a range of the wireless device from the modulated radar signal.

1 . A method comprising:
 transmitting, from a detecting system, a continuous wave radar signal with a carrier frequency corresponding to a transmit frequency channel for a complex modulation scheme;   in response to the continuous wave radar signal, receiving from a wireless device a backscattered complex modulated signal offset by a frequency offset corresponding to a receive frequency channel;   determining an identity of the wireless device from information pertaining to the wireless device contained in the received complex modulated signal; and   determining a range of the wireless device from the received complex modulated signal.   
     
     
         2 . The method of  claim 1 , wherein the backscattered complex modulated signal is selected from the group consisting of Gaussian Minimum Shift Keying (GMSK), Quadrature Phase Shift Keying (QPSK), n-constellation Phase Shift Keying (nPSK), 8-constellation Phase Shift Keying (8PSK), multi-phase PSK, Orthogonal Frequency-Division Multiplexing (OFDM), Quadrature Amplitude Modulation (QAM), n-constellation Quadrature Amplitude Modulation (nQAM), Amplitude Shift Keying (ASK), multi-amplitude ASK, and on-off keying ( 00  K). 
     
     
         3 . The method of  claim 1 , wherein the continuous wave signal is selected from the group consisting of a sine wave, a saw tooth wave, a triangle wave, a square wave, and a chirp signal. 
     
     
         4 . The method of  claim 1 , wherein determining the range of the wireless device from the received complex modulated signal comprises:
 determining a frequency offset from a center frequency of the frequency channel; and   determining a range of the wireless device from the frequency offset.   
     
     
         5 . The method of  claim 1 , wherein the identity is an identification number contained in the information pertaining to the wireless device. 
     
     
         6 . The method of  claim 1 , further comprising:
 measuring a power of the received complex modulated signal; and   determining the range based on the power of the received complex modulated signal.   
     
     
         7 . The method of  claim 1 , wherein the detecting system is or is included in another wireless device. 
     
     
         8 . The method of  claim 1 , wherein the range is a distance between the detecting system and the wireless device. 
     
     
         9 . The method of  claim 1 , wherein the detecting system is a Radio Frequency Identification (RFID) reader. 
     
     
         10 . The method of  claim 1 , wherein the wireless device is a Radio Frequency Identification (RFID) tag. 
     
     
         11 . An apparatus comprising:
 a radio frequency (RF) transmitter;   an RF receiver;   a processor coupled to memory, the RF transmitter, and the RF receiver;   a non-transitory computer-readable medium storing instructions that are operative, when executed on the processor, to perform the functions of:
 transmitting, from a detecting system, a continuous wave radar signal with a carrier frequency corresponding to a transmit frequency channel for a complex modulation scheme; 
 in response to the continuous wave radar signal, receiving from a wireless device a backscattered complex modulated signal offset by a frequency offset corresponding to a receive frequency channel; 
 determining an identity of the wireless device from information pertaining to the wireless device contained in the received complex modulated signal; and 
 determining a range of the wireless device from the received complex modulated signal. 
   
     
     
         12 . The apparatus of  claim 11 , wherein the complex modulation scheme is selected from the group consisting of Gaussian Minimum Shift Keying (GMSK), Quadrature Phase Shift Keying (QPSK), n-constellation Phase Shift Keying (nPSK), 8-constellation Phase Shift Keying (8PSK), multi-phase PSK, Orthogonal Frequency-Division Multiplexing (OFDM), Quadrature Amplitude Modulation (QAM), n-constellation Quadrature Amplitude Modulation (nQAM), Amplitude Shift Keying (ASK), multi-amplitude ASK, and on-off keying ( 00  K). 
     
     
         13 . The apparatus of  claim 11 , wherein the continuous wave radar signal is selected from the group consisting of a sine wave, a saw tooth wave, a triangle wave, a square wave, and a chirp signal. 
     
     
         14 . The apparatus of  claim 11 , wherein a non-transitory computer-readable medium storing instructions for determining the range of the wireless device from the received complex modulated signal comprises:
 a module for determining a frequency offset from a center frequency of the frequency channel; and   a module for determining a range of the wireless device from the frequency offset.   
     
     
         15 . The apparatus of  claim 11  wherein the identity is an identification number contained in the information pertaining to the wireless device. 
     
     
         16 . The apparatus of  claim 11  and further comprising:
 a module for measuring a power of the received complex modulated signal at the system; and 
 a module for determining the range based on the power of the received complex modulated signal. 
 
     
     
         17 . The apparatus of  claim 11  wherein the system is or is included in another wireless device. 
     
     
         18 . The apparatus of  claim 11  wherein the range is a distance between the detecting system and the wireless device. 
     
     
         19 . The apparatus of  claim 11  wherein the system is a radio frequency identification (“RFD”) reader. 
     
     
         20 . The apparatus of  claim 11  wherein the wireless device is a radio frequency identification (“RFD”) tag.