Direction estimating apparatus, directivity controlling antenna apparatus, and direction estimating method

A directivity controlling antenna apparatus comprising:

• a first array antenna comprising a plurality of antennas as array elements, the array elements being arranged at respective different heights from a ground so as not to overlap each other in a vertical direction;
• a received frequency conversion system that converts a radio frequency signal of an arriving radio signal received at each of the array elements into an analog output signal, the analog output signal comprising one of an intermediate frequency signal and a baseband signal;
• an A/D conversion system that converts the analog output signal from the received frequency conversion system into a digital signal;
• a direction estimating system that estimates a horizontal direction and a vertical direction of the arriving radio signal using the digital signal output from the A/D conversion system;
• a reception weight calculating system that obtains a reception weight based on the digital signal and on the horizontal direction and the vertical direction of the arriving radio signal estimated in the direction estimating system.

A direction estimating apparatus comprising:

• an array antenna comprising a plurality of antennas as array elements, the array elements being arranged at respective different heights from a ground such that the array elements do not overlap in a vertical direction;
• a received frequency conversion system that converts a radio frequency signal of an arriving radio signal received at each of the array elements into an analog output signal, the analog output signal comprising one of an intermediate frequency signal and a baseband signal;
• an A/D conversion system that converts the analog output signal from the received frequency conversion system into a digital signal;
• and
• an IQ generating system that generates an in-phase component signal and a quadrature component signal intermittently and aperiodically from the digital signal output from the A/D conversion system;
• and
• a direction estimating system that estimates a horizontal direction and a vertical direction of the arriving radio signal based on the in-phase component signal and the quadrature component signal output from the IQ generating system.

A directivity controlling antenna apparatus comprising:

• a third array antenna comprising a plurality of antennas as array elements;
• a received frequency conversion system that converts a radio frequency signal received at each of the array elements into one of an intermediate frequency signal and a baseband signal;
• an A/D conversion system that converts an analog signal output from the received frequency conversion system into a digital signal;
• an IQ generating system that generates an in-phase component signal and a quadrature component signal intermittently and aperiodically from the digital signal output from A/D conversion system;
• a direction estimating system that estimates a horizontal direction and a vertical direction of an arriving radio signal using the in-phase component signal and the quadrature component signal output from the IQ generating system;
• a reception weight calculating system that obtains a reception weight based on the horizontal direction and the vertical direction of the arriving radio signal estimated in the direction estimating system and the digital signal;
• and
• a reception beam forming system that performs directional combining for the third array antenna using the reception weight obtained in the reception weight calculating system.

A direction estimating apparatus comprising:

• an array antenna using a plurality of antennas as array elements;
• a received frequency conversion system that converts a radio frequency signal received at each of the array elements into one of an intermediate frequency signal and a baseband signal;
• an A/D conversion system that converts an analog output signal output from the received frequency conversion system into a digital signal;
• an IQ generating system that generates an in-phase component signal and a quadrature component signal intermittently and aperiodically from the digital signal output from the A/D conversion system;
• and
• a direction estimating system that estimates a horizontal direction and a vertical direction of an arriving radio signal using the in-phase component signal and the quadrature component signal output from the IQ generating system.