Apparatus for high accuracy distance and velocity measurement and methods thereof

Abstract

A system and method for measuring a parameter of a target in accordance with embodiments of the present invention includes transmitting at least one signal towards a target and receiving at least a portion of the transmitted signal back from the target. The measured parameter is one of distance velocity, or reflectivity. The transmitted signal is of the coherent burst waveform, and upon reception is processed with equivalent time sampling, AGC with minimal, if any, error, and a discrete Fourier transform.

1 . A method for measuring a parameter of a target, the method comprising:
 transmitting at least one coherent burst signal towards a target;   receiving at least one of a return signal sent in response to a detection of the transmitted signal at the target and at least a portion of the transmitted signal back from the target; and   determining a parameter of a target based on the received signal and using a discrete Fourier transform.   
   
   
       2 . The method as set forth in  claim 1  wherein the parameter is a distance to the target. 
   
   
       3 . The method as set forth in  claim 1  further comprising generating a signal for the transmitting. 
   
   
       4 . The method as set forth in  claim 3  further comprising filtering the generated signal, wherein the filtering generates a sinusoidal signal for the transmitting. 
   
   
       5 . The method as set forth in  claim 3  further comprising encoding data on the generated signal for the transmitting. 
   
   
       6 . The method as set forth in  claim 1  wherein the coherent burst signal has a power of less than about 5 mW. 
   
   
       7 . The method as set forth in  claim 6  wherein the coherent burst signal has an average power of less than about 1 mW. 
   
   
       8 . The method as set forth in  claim 1  further comprising amplifying and filtering the signal. 
   
   
       9 . The method as set forth in  claim 1  further comprising determining a phase offset from a baseline, wherein the determining the parameter further comprises determining the parameter based on the phase offset. 
   
   
       10 . The method as set forth in  claim 1  further comprising using a look-up table to correct for one or more errors in the parameter. 
   
   
       11 . The method as set forth in  claim 1  further comprising determining a refractive index of a medium in which the transmitted signal propagates, wherein the determining the parameter further comprises determining the parameter based on the refractive index of the medium. 
   
   
       12 . The method as set forth in  claim 11  wherein the determining the refractive index further comprises obtaining a temperature reading and a pressure reading of the medium, wherein the determining the refractive index is based on the temperature reading and the pressure reading. 
   
   
       13 . The method as set forth in  claim 1  further comprising:
 adding a code on to the coherent burst signal before the transmitting; and   preventing the determining the parameter of the target until a code on the received signal substantially matches the added code.   
   
   
       14 . The method as set forth in  claim 1  wherein the parameter is a measured distance to the target and further comprising:
 comparing the measured distance against a threshold distance; and   providing a collision alert when the comparing indicates the measured distance is less than the threshold distance.   
   
   
       15 . The method as set forth in  claim 1  wherein the parameter is a velocity of the target. 
   
   
       16 . The method as set forth in  claim 15  wherein the determining the parameter further comprises determining the parameter based on a phase difference between at least two of the received signals. 
   
   
       17 . The method as set forth in  claim 1  wherein the parameter is a reflectivity of the target. 
   
   
       18 . The method as set forth in  claim 1  wherein the transmitted signal is a binary signal. 
   
   
       19 . The method as set forth in  claim 1  wherein the transmitted signal is electromagnetic energy. 
   
   
       20 . The method as set forth in  claim 1  wherein the transmitted signal is acoustic energy. 
   
   
       21 . The method as set forth in  claim 1  wherein the transmitting further comprises transmitting the signal to substantially covers the target, wherein the receiving further comprises receiving portions of the transmitted signal back from different parts of the target, wherein the determining the parameter further comprises determining one or more parameters for each of the received signals from the different parts of the target and further comprising constructing an image of the target based on the determined parameters. 
   
   
       22 . The method as set forth in  claim 1  wherein the determining the parameter further comprises:
 selecting multiple portions of the received signal; and   determining the parameter based on an average of phase differences between the transmitted signal and the multiple portions of the received signal.   
   
   
       23 . A system for measuring a parameter of a target, the system comprising:
 a transmission system that transmits at least one coherent burst signal towards a target;   a receiving system that receives at least one of a return signal sent in response to a detection of the transmitted signal at the target and at least a portion of the transmitted signal back from the target; and   a parameter processing system that determines a parameter of a target based on the received signal and using a discrete Fourier transform   
   
   
       24 . The system as set forth in  claim 23  wherein the parameter is a distance to the target. 
   
   
       25 . The system as set forth in  claim 23  further comprising a coherent burst signal generation system that generates the coherent burst signal for the transmission system. 
   
   
       26 . The system as set forth in  claim 25  further comprising a filtering system that filters the generated signal, wherein the filtering system generates a sinusoidal signal for the transmission system. 
   
   
       27 . The system as set forth in  claim 25  further comprising an encoding system that encodes data on the generated signal for the transmission system. 
   
   
       28 . The system as set forth in  claim 23  wherein the coherent burst signal has a power of less than about 5 mW. 
   
   
       29 . The system as set forth in  claim 28  wherein the coherent burst signal has an average power of less than about 1 mW. 
   
   
       30 . The system as set forth in  claim 23  further comprising an amplification and filtering system that amplifies and filters the coherent burst signal. 
   
   
       31 . The system as set forth in  claim 23  wherein the parameter processing system determines a phase offset from a baseline and further bases the determination of the parameter on the phase offset. 
   
   
       32 . The system as set forth in  claim 23  wherein the parameter processing system further comprises a look-up table that is used by the parameter processing system to correct for one or more errors in the parameter. 
   
   
       33 . The system as set forth in  claim 23  further comprising a refractive index determination system that determines a refractive index of a medium in which the transmitted signal propagates, wherein the parameter processing system further bases the determination of the parameter on the refractive index of the medium. 
   
   
       34 . The system as set forth in  claim 33  wherein the refractive index determination system obtains a temperature reading and a pressure reading of the medium, wherein the refractive index determination system further bases the determination of the refractive index on the temperature reading and the pressure reading. 
   
   
       35 . The system as set forth in  claim 23  further comprising:
 a coding system that adds a code on to the coherent burst signal before the transmitting; and   a security system that prevents the parameter processing system from determining the parameter of the target until a code on the received signal substantially matches the added code.   
   
   
       36 . The system as set forth in  claim 23  wherein the parameter is a measured distance to the target and further comprising:
 a comparison system that compares the measured distance against a threshold distance; and   a notification system that provides a collision alert when the comparing indicates the measured distance is less than the threshold distance.   
   
   
       37 . The system as set forth in  claim 23  wherein the parameter is a velocity of the target. 
   
   
       38 . The system as set forth in  claim 37  wherein the parameter processing system further bases the determination of the parameter on a phase difference between at least two of the received signals. 
   
   
       39 . The system as set forth in  claim 23  wherein the parameter is a reflectivity of the target. 
   
   
       40 . The system as set forth in  claim 23  wherein the coherent burst signal is a binary signal. 
   
   
       41 . The system as set forth in  claim 23  wherein the coherent burst signal is electromagnetic energy. 
   
   
       42 . The system as set forth in  claim 23  wherein the coherent burst signal is acoustic energy. 
   
   
       43 . The system as set forth in  claim 23  wherein the transmission system transmits the coherent burst signal to substantially cover the target, wherein the receiving system receives portions of the transmitted signal back from different parts of the target, wherein the parameter processing system determines one or more parameters for each of the received signals from the different parts of the target and constructs an image of the target based on the determined parameters. 
   
   
       44 . The system as set forth in  claim 23  wherein the parameter processing system selects multiple portions of the received signal and determines the parameter based on an average of phase differences between the transmitted signal and the multiple portions of the received signal.