Arrival direction estimation apparatus

An arrival direction estimation apparatus comprising:

• an antenna in which a plurality of antenna elements are arranged and which receives signals by the plurality of antenna elements;
• a complex digital signal converting means which converts the signals received by each antenna element of the antenna to complex digital signals;
• a correlation matrix calculating means which calculates a correlation matrix expressing correlation among the plurality of antenna elements of the complex digital signals;
• a weight matrix calculating means which calculates a weight matrix used for calculating a spectrum based on the calculated correlation matrix;
• a spectrum calculating means which calculates the spectrum based on the calculated weight matrix and a vector indicating directivity of the antenna;
• a spectrum peak detecting means which detects a direction with a peak value with the use of the calculated spectrum result;
• and
• an arrival direction calculating means which estimates an arrival direction of the signals based on spectrum results in the direction detected by the spectrum peak detecting means and peripheral directions thereof.

An arrival direction estimation apparatus comprising:

• an antenna in which a plurality of antenna elements are symmetrically arranged centering on a given reference position or a reference line and which receives signals by the plurality of antenna elements;
• a complex digital signal converting means which converts the signals received by each antenna element of the antenna to complex digital signals;
• a real number correlation matrix calculating means which calculates a real number correlation matrix expressing correlation among the plurality of antenna elements of the complex digital signals;
• a real number weight matrix calculating means which calculates a real number weight matrix used for calculating a spectrum based on the calculated real number correlation matrix;
• an inverse unitary converting means which provides the calculated real number weight matrix with inverse unitary conversion to calculate a complex weight matrix;
• a spectrum calculating means which provides the calculated complex weight matrix with Fast Fourier Transform to calculate the spectrum;
• a spectrum peak detecting means which detects a direction with a peak value with the use of the calculated spectrum result;
• and
• an arrival direction calculating means which estimates an arrival direction of the signals based on spectrum results at the direction detected by the spectrum peak detecting means and peripheral directions thereof.