System and method for sensing distance and/or movement

Abstract

A method (e.g., a method for measuring a separation distance to a target object) includes transmitting an electromagnetic first transmitted signal from a transmitting antenna toward a target object that is a separated from the transmitting antenna by a separation distance. The first transmitted signal includes a first transmit pattern representative of a first sequence of digital bits. The method also includes receiving a first echo of the first transmitted signal that is reflected off the target object, converting the first echo into a first digitized echo signal, and comparing a first receive pattern representative of a second sequence of digital bits to the first digitized echo signal to determine a time of flight of the first transmitted signal and the echo.

1 . A digital radar method comprising the steps of:
 generating a transmission signal from a transmission sequence including a digital transmit pattern;   transmitting the transmission signal from a first antenna;   receiving an analog echo signal at a second antenna, the analog echo signal including reflections of the transmission signal off one or more objects;   generating a baseband echo signal from the analog echo signal;   prior to performing any comparisons with any echo signal, digitizing the baseband echo signal to generate a digital echo pattern; and   comparing the digital echo pattern to a digital receive pattern.   
     
     
         2 . The digital radar method of  claim 1 , wherein generating the transmission signal includes inserting the digital transmit pattern into a digital stream to create the transmission sequence. 
     
     
         3 . The digital radar method of  claim 1 , wherein generating the transmission signal includes identifying the digital transmit pattern in a digital stream to create the transmission sequence. 
     
     
         4 . The digital radar method of  claim 1 , further comprising:
 calculating a time of flight of the transmission signal based on the compared signal.   
     
     
         5 . The digital radar method of  claim 4 , further comprising:
 calculating a separation distance from the first antenna to the one or more objects based on the time of flight.   
     
     
         6 . The digital radar method of  claim 1 , wherein the digital transmit pattern is representative of a first sequence of bits and the digital receive pattern is representative of a second sequence of bits. 
     
     
         7 . The digital radar method of  claim 6 , wherein the first sequence of bits and the second sequence of bits are different. 
     
     
         8 . The digital radar method of  claim 6 , wherein the first sequence of bits and the second sequence of bits are the same. 
     
     
         9 . The digital radar method of  claim 7 , wherein the difference between the first sequence of bits and second sequence of bits is at least one of:
 bit length, and   one or more bit value differences.   
     
     
         10 . The digital radar method of  claim 6 , wherein comparing the digital echo pattern to the digital receive pattern further comprises:
 comparing the second sequence of bits to segments of the digital echo pattern to calculate correlation values for each segment, each correlation value representing a degree of match between the second sequence of bits and each segment of the digital echo pattern.   
     
     
         11 . The digital radar method of  claim 10 , wherein at least one segment of the digital echo pattern is identified as a segment of interest based on its correlation value exceeding a threshold value, and
 wherein the time of flight is determined based on a time delay between transmission of the transmitted signal and an occurrence time of the segment of interest determined from the digital echo pattern.   
     
     
         12 . The digital radar method of  claim 1 , wherein the digital transmit pattern includes a plurality of repeating patterns. 
     
     
         13 . The digital radar method of  claim 1 , wherein the digital transmit pattern includes a plurality of different patterns provided sequentially. 
     
     
         14 . The digital radar method of  claim 1 , wherein the first and second antennas are the same antenna. 
     
     
         15 . The digital radar method of  claim 1 , wherein at least one of the first and second antennas is directional. 
     
     
         16 . A digital radar system comprising:
 a transmitter configured to generate a transmission signal from a transmission sequence including a digital transmit pattern and transmit the transmission signal from a first antenna;   a receiver configured to receive an analog echo signal at a second antenna, to generate a baseband echo signal from the analog echo signal, and prior to performing any comparisons with any echo signal, to digitize the received baseband echo signal to generate a digital echo pattern, and   a correlator configured to compare the digital echo pattern to a digital receive pattern,   wherein the analog echo signal includes reflections of the transmission signal off one or more objects.   
     
     
         17 . The digital radar method of  claim 16 , wherein generating the transmission signal includes inserting the digital transmit pattern into a digital stream to create the transmission sequence. 
     
     
         18 . The digital radar method of  claim 16 , wherein generating the transmission signal includes identifying the digital transmit pattern in a digital stream to create the transmission sequence. 
     
     
         19 . The digital radar system of  claim 16 , further comprising:
 a processor configured to calculate a time of flight of the transmission signal based on the compared signal.   
     
     
         20 . The digital radar system of  claim 19 , wherein the processor is further configured to calculate a separation distance from the transmitter to the one or more objects based on the time of flight. 
     
     
         21 . The digital radar system of  claim 16 , wherein the digital transmit pattern is representative of a first sequence of bits and the digital receive pattern is representative of a second sequence of bits. 
     
     
         22 . The digital radar system of  claim 21 , wherein the first sequence of bits and the second sequence of bits are different. 
     
     
         23 . The digital radar method of  claim 21 , wherein the first sequence of bits and the second sequence of bits are the same. 
     
     
         24 . The digital radar system of  claim 22 , wherein the difference between the first sequence of bits and second sequence of bits is at least one of:
 bit length, or   one or more bit value differences.   
     
     
         25 . The digital radar system of  claim 21 , wherein the correlator is further configured to compare the second sequence of bits to segments of the digital echo pattern to calculate correlation values for each segment, each correlation value representing a degree of match between the second sequence of bits and each segment of the digital echo pattern. 
     
     
         26 . The digital radar system of  claim 25 , wherein at least one segment of the digital echo pattern is identified as a segment of interest based on its correlation value exceeding a threshold value, and
 wherein the time of flight is determined based on a time delay between transmission of the transmitted signal and an occurrence time of the segment of interest determined from the digital echo pattern.   
     
     
         27 . The digital radar system of  claim 16 , wherein the digital transmit pattern includes a plurality of repeating patterns. 
     
     
         28 . The digital radar system of  claim 16 , wherein the digital transmit pattern includes a plurality of different patterns provided sequentially. 
     
     
         29 . The digital radar system of  claim 16 , wherein the first and second antennas are the same antenna. 
     
     
         30 . The digital radar system of  claim 16 , wherein at least one of the first and second antennas is directional.