Systems and methods for sensing the surroundings of a vehicle

Abstract

Systems and methods for sensing the surroundings of vehicles via vehicle mounted radar sensors. A directional transmitter array transmits radiation into the region surrounding the vehicle and a receiver array receives the radiation reflected back. Controllers may use self-velocity calculation modules, wall detection modules, dynamic range enhancement modules, double reflection detection modules and the like to harvest useful information such as the vehicles relative speed and the identification of hazards in its surroundings.

What is claimed is: 
     
         1 . A system for sensing the surroundings of a vehicle comprising:
 a vehicle mounted radar unit comprising:
 a radar transmission unit comprising an array of transmitter antennas connected to an oscillator and configured to transmit electromagnetic waves into a region surrounding the vehicle, and 
 a radar receiving unit comprising at least one receiver antenna configured to receive electromagnetic waves reflected by objects within the region surrounding the vehicle and operable to generate raw data; 
   a processor unit in communication with the radar receiving unit and configured to receive raw data from the radar unit and operable to generate environmental information based upon the received data;   wherein the processor comprises a self velocity calculation module operable to calculate velocity of the vehicle from raw data; and   wherein the self-velocity calculation module is operable to determine a horizontal shift, dx, for detected reflecting objects; and to calculate a gradient of a plot of apparent radial velocity V R  as a function of horizontal shift dx for the reflecting objects.   
     
     
         2 . The system of  claim 1  wherein the self-velocity calculation module comprises an image generation unit and a memory unit. 
     
     
         3 . The system of  claim 2  wherein the image generation unit is configured and operable to construct a three dimensional image representing a region surrounding the vehicle comprising a matrix of voxels. 
     
     
         4 . The system of  claim 3  wherein each voxel characterized by a set of voxel parameters including:
 a horizontal spatial coordinate, x, of a reflecting object along an axis parallel to the path of the vehicle; 
 a vertical spatial coordinate, y, of the reflecting object along a vertical axis orthogonal to the path of the vehicle; 
 a radial spatial coordinate, R, of the reflecting object along an axis diverging radially from the vehicle; 
 an intensity value; and 
 a Doppler-shift value indicating an apparent radial velocity V R  of the reflecting object. 
 
     
     
         5 . The system of  claim 2  wherein the memory unit configured to store data pertaining to at least:
 a first three dimensional image representing the region surrounding the vehicle at a first instant, and 
 a second three dimensional image representing the region surrounding the vehicle at a second instant after a delay time, dt. 
 
     
     
         6 . The system of  claim 1  wherein the processor is operable to determine horizontal shift, dx, by: 
 determining an x-coordinate, xn, for the reflecting object; 
 determining a y-coordinate, yn, for the reflecting object; 
 finding the reflecting object’s co-altitude angle, θn, by calculating the arctangent of the ratio (xn/yn) of the x-coordinate of the reflecting object and the y-coordinate of the reflecting object an angle; 
 calculating the sine of the co-altitude angel such that dx=sin(arctan(xn/yn)). 
 
     
     
         7 . The system of  claim 1  wherein the processor further comprises a wall detection module operable to detect planar surfaces in the region surrounding the vehicle. 
     
     
         8 . The system of  claim 7  wherein the wall detection module comprises a processing unit, and a memory unit storing executable code directed towards comparing energy-profile within a virtual box with a reference energy-profile indicative of a two dimensional reflector. 
     
     
         9 . The system of  claim 1  wherein the radar transmission unit further comprises a polarizer configured and operable to generate circularly polarized electromagnetic waves. 
     
     
         10 . The system of  claim 1  wherein the radar receiving unit further comprises a polarization detector configured and operable to detect the polarization of the received electromagnetic waves. 
     
     
         11 . The system of  claim 1  further comprising a double-reflection identification module comprising:
 a circular polarizer configured and operable to generate circularly polarized electromagnetic waves; and 
 a polarization detector configured and operable to detect the polarization of the received electromagnetic waves. 
 
     
     
         12 . A system for sensing the surroundings of a vehicle comprising:
 a vehicle mounted radar unit comprising:
 a radar transmission unit comprising an array of transmitter antennas connected to an oscillator and configured to transmit electromagnetic waves into a region surrounding the vehicle, and 
 a radar receiving unit comprising at least one receiver antenna configured to receive electromagnetic waves reflected by objects within the region surrounding the vehicle and operable to generate raw data; 
   a processor unit in communication with the radar receiving unit and configured to receive raw data from the radar unit and operable to generate environmental information based upon the received data;   wherein the processor comprises a wall detection module operable to detect planar surfaces in the region surrounding the vehicle.   
     
     
         13 . The system of  claim 12  wherein the wall detection module comprises a processing unit, and a memory unit storing executable code directed towards comparing energy-profile within a virtual box with a reference energy-profile indicative of a two dimensional reflector. 
     
     
         14 . The system of  claim 12  wherein the wall detection module is configured and operable to detect a two dimensional extended target in the region surrounding a vehicle, by:
 constructing virtual box around volume containing a candidate wall-object; 
 calculating energy-profile for the radar image within the virtual box; and 
 applying a classification function to the energy-profile. 
 
     
     
         15 . The system of  claim 14  wherein the step of applying a classification function comprises calculating at least one wall-indication parameter selected from a group consisting of: overall energy reflected from within virtual box; profile of reflected energy from within virtual box segments; number of voxels within virtual box having energy values above a threshold value; and combinations thereof. 
     
     
         16 . A method for detecting a two dimensional extended target in the region surrounding a vehicle, the method comprising:
 providing a vehicle mounted radar unit;   transmitting electromagnetic radiation into the region surrounding the vehicle;   receiving electromagnetic radiation reflected from an object in the region surrounding the vehicle;   detecting a spectral-reflection point in reflected radiation;   constructing virtual box around volume containing a candidate wall-object;   calculating energy-profile for the radar image within the virtual box;   applying a classification function to the energy-profile.   
     
     
         17 . The method of  14  wherein the step of applying a classification function comprises calculating at least one wall-indication parameter selected from a group consisting of: overall energy reflected from within virtual box; profile of reflected energy from within virtual box segments; number of voxels within virtual box having energy values above a threshold value; and combinations thereof.