Method and apparatus for improved determination of range and angle of arrival utilizing a two tone CW radar

A system for determining range and angle of arrival of a target moving relative to a two-tone CW radar from which sum and difference signals for the two frequencies associated with the two tones are available, comprising:

• a down converter for down-converting, low pass filtering and sampling said sum and difference signals;
• a demultiplexer for providing time domain data streams corresponding to the down-converted, low pass filtered and sampled sum and difference signals;
• a module coupled to said demultiplexer for performing a Fast Fourier Transform on said time-domain data stream to produce associated frequency domain data streams in the form of individual frequency bins;
• a calculator for squaring the magnitude of the individual bins to produce magnitude-squared values;
• an accumulator for accumulating said magnitude-squared values;
• a peak search detector for determining from the accumulated magnitude-squared values which of said frequency bins has the highest peak, thus to determine which of said frequency bins contains said target;
• a processor for generating a first two-by-two matrix from the sum and difference values associated with the bin that is determined to contain said target;
• and,
• a unit for performing a singular value decomposition of said first two-by-two matrix so as to factor said first matrix into a second and third matrix respectively related to range and angle of arrival.

Apparatus for determining range and angle of arrival of a target moving relative to a two-tone CW radar from which sum and difference signals for the two frequencies associated with the two tones are available, comprising:

• means for forming frequency bins for said sum and difference signals;
• a peak detector for determining which of said frequency bins contains said target;
• a matrix generator for generating a first two-by-two matrix from the sum and difference signals in the frequency bin containing said target;
• and,
• a factoring unit for factoring said first matrix into second and third two-by-two matrices having respective first columns containing information related respectively to the range and angle of arrival of said target, thus to determine the range and angle of arrival of said target.