Selectable range lobes using wide-band array

Abstract

The present inventive concept for bistatic or monostatic radar utilization discloses a method and a system for unambiguous range resolution utilizing an ultra wide-band signal, generally a wide-band noise signal which may be continuous bandwidth limited white or colored noise. The noise signal is typically generated and radiated by a transmitting antenna covering the entire reception range of a receiving sparse antenna. An echo signal is received by the receiving antenna. By means of a selected auto-correlation function defining the wide-band noise signal power spectrum, the convolution of the radiated output signal and the received echo input signal will give the target range information.

1 . A system for controlled range side-lobes in a bistatic or monostatic radar system, characterized in that 
 an ultra wide-band band microwave signal is generated and radiated via a transmitter antenna, echo signals are received via receiver antennas;    whereby a transmitted power spectrum of a transmitted signal and its auto-correlation function form a Fourier transform pair, such that for a given range sidelobe characteristic the power spectrum of a corresponding output signal is calculated as an inverse Fourier transform of given range sidelobe characteristic.    
   
   
       2 . The system according to  claim 1 , characterized in that the ultra wide-band microwave signal is generated as band-limited white noise, the convolution result being read out as a signature of the target for 100% bandwidth approximately in form of the derivative of the target area as function of range.  
   
   
       3 . The system according to  claim 1 , characterized in that the ultra wide-band microwave signal is generated as band-limited colored noise, by using a selected auto-correlation function for the generated noise.  
   
   
       4 . The system according to  claim 1 , characterized in that the ultra wide-band microwave signal comprises a frequency range of the same order as the center frequency.  
   
   
       5 . The system according to  claim 1 , characterized in that the antenna used are vertical linear arrays.  
   
   
       6 . The system according to  claim 1 , characterized in that the receiver antennas form a circular array.  
   
   
       7 . The system according to  claim 1 , characterized in that in an monostatic configuration an omnidirectional transmitting antenna is generally positioned at another height than receiving antennas to minimize leakage between transmit and receive antennas.  
   
   
       8 . A method for obtaining controlled range side-lobes in a bistatic or monostatic radar operation, characterized by the steps of 
 generating an ultra wide-band band microwave signal being radiated via a transmitter antenna;    arranging receiving microwave antennas;    forming a Fourier transform pair with a transmitted power spectrum of transmitted signal and its auto-correlation function;    calculating for a given range sidelobe characteristic the power spectrum of the corresponding output signal as the inverse Fourier transform of the given range sidelobe characteristic.    
   
   
       9 . The method according to  claim 8 , characterized by the further steps of generating the ultra wide-band microwave signal as band-limited white noise, and reading out the convolution result as a signature of the target for 100% bandwidth approximately in form of the derivative of the target area as function of range.  
   
   
       10 . The method according to  claim 8 , characterized by the further step of generating the ultra wide-band microwave signal as band-limited colored noise by using a selected auto-correlation function for the generated noise.  
   
   
       11 . The method according to  claim 8 , characterized by the further step of generating the ultra wide-band microwave signal in a frequency range having an order about equal to the value of the center frequency.  
   
   
       12 . The method according to  claim 8 , characterized by the further step of using vertical linear arrays as antennas.  
   
   
       13 . The method according to  claim 8 , characterized by the further step of using circular arrays as receiving antenna.  
   
   
       14 . The method according to  claim 8 , characterized by the further step of in a monostatic configuration generally positioning an omnidirectional transmitting antenna at a different height compared to the receiving antennas to minimize leakage between transmit and receive antennas.