Aggregate beamformer for use in a directional receiving array

A method of creating a virtual beam in a desired beam direction from an array of analog signal components, the method comprising the steps of:

• providing a random sequence of indices of said array and providing an associated sequence of time delays, the random sequence of indices having specific statistical properties;
• sampling the analog signal components to provide a sequence of sampled digital signal components;
• providing a time alignment between the digital signal components, according to the sequence of time delays, the time alignment providing coherent reinforcement of the signals arriving from the beam direction;
• and
• filtering the time aligned signal components for selecting a desired signal frequency band and eliminating noise outside the band;
• and
• wherein the step of sampling the analog signal components is selected from the group consisting of step a) and step b), where:
• step a) comprises:
• (i) first, digitizing individual analog signal components of said array to generate an aggregate digital signal comprising digital signal components, and
• (ii) second, selecting individual digital signal components of said array in a sequence based on the specific statistical properties to provide the sequence of sampled digital signal components;
• and
• step b) comprises:
• (i) first, selecting individual analog signal components of said array in a sequence based on the specific statistical properties;
• and
• (ii) second, digitizing the analog signal components of said array to generate an aggregate digital signal comprising digital signal components to provide the sequence of sampled digital signal components.

A beamformer for creating a virtual beam in a target beam direction from an array of analog signal components associated with input elements, the beamformer comprising:

• a sequencing unit for establishing a set of indices defining random sequence having specific statistical properties, said random sequence determining a sequencing order for said analog signal components, and for establishing a set of associated time delay indices based on said sequencing order and said target beam direction;
• an over-sampling unit for sampling said analog signal components to provide a set of sampled digital signal components in said sequencing order;
• an alignment unit for providing a time alignment between the digital signal components based on said time delay indices, said, time alignment providing coherent reinforcement of the signals arriving from said target beam direction;
• and
• a down-filter for filtering the time aligned signal to select a specific signal frequency band and eliminate noise outside said specific frequency band.

A beamformer for creating a virtual beam in a desired beam direction from an array of analog signal components, the beamformer comprising:

• a sequencing unit for providing a random sequence of indices of said array and providing an associated sequence of time delays, the random sequence of indices including specific statistical properties;
• a sampling unit for providing a sequence of sampled digital signal components;
• an alignment unit for providing a time alignment between the digital signal components, according to the sequence of time delays, the time alignment providing coherent reinforcement of the signals arriving from the beam direction;
• and
• a filter for filtering the time aligned signal for selecting a desired signal frequency band and eliminating noise outside the band;
• wherein the sampling unit is selected from the group consisting of subunit a) and subunit b), where:
• subunit a) comprises:
• (i) an analog to digital converter for firstly, digitizing individual analog signal components of said array to generate an aggregate digital signal comprising digital signal components;
• and
• (ii) a channel selector for secondly selecting individual digital signal components of said array in a sequence based on the specific statistical properties to provide the sequence of sampled digital signal components;
• and
• subunit b) comprises:
• (i) a channel selector for firstly selecting individual digital signal components of said array in a sequence based on the specific statistical properties to provide the sequence of sampled digital signal components;
• and
• (ii) an analog to digital converter for secondly, digitizing individual analog signal components of said array to generate an aggregate digital signal comprising digital signal components.

A beamformer which combines an array of analog signal components from an array of input elements to obtain an output signal for a beam steering direction according to the equation:

• y θ ⁢ ( n ⁢ ⁢ K o ⁢ ⁢ v ⁢ ⁢ e ⁢ ⁢ r ⁢ Δ ⁢ ⁢ t ) = ∑ k ⁢ h ⁢ ( k ) ⁢ x σ ⁢ ( n ⁢ ⁢ K over - k ) ⁢ ( ( n ⁢ ⁢ K over - k ) ⁢ Δ ⁢ ⁢ t - d n )
• wherein
• yθ(nKoverΔt) is the beamformer output signal for beam direction θ;
• h represents the impulse response of a digital decimation filter;
• s(n) is a random sequence of input element numbers adjusted for collision management;
• xm is the m-th analog signal component;
• n is a sample number;
• k is a summation index;
• Kover is an over-sampling factor and is >>1;
• Δt is the time interval between samples at an analog to digital converter;
• and
• dm are time delays that determine the direction in which the response is maximized, adjusted for collision management.