Method and apparatus for improving noise discrimination in multiple sensor pairs
View Patent ↗Noise discrimination in signals from a plurality of sensors is conducted by enhancing the phase difference in the signals such that off-axis pick-up is suppressed while on-axis pick-up is enhanced. Alternatively, attenuation/expansion are applied to the signals in a phase difference dependent manner, consistent with suppression of off-axis pick-up and on-axis enhancement. Nulls between sensitivity lobes are widened, effectively narrowing the sensitivity lobes and improving directionality and noise discrimination.
1. A method for improving noise discrimination in a system having a plurality of sensors each configured to generate an input signal representable by an input vector having a phase component and a magnitude component, the plurality of sensors arranged to have an on-axis direction, the method comprising:
generating an input electrical signal from each of the plurality of sensors;
processing the input electrical signals from the plurality of sensors, said processing including:
using the input electrical signals from a first pair of sensors to obtain a coarse vector phase difference corresponding to a coarse measurement of an angle of arrival of a signal input source relative to the on-axis direction;
using the input electrical signals from a second pair of sensors to obtain a fine vector phase difference corresponding to a fine measurement of the angle of arrival of the signal input source;
generating an input phase difference value from the coarse and fine vector phase differences;
enhancing the input phase difference value as a function of the angle of arrival to generate an output phase difference value;
generating first and second output vectors having a phase difference based on the output phase difference value; and
combining the first and second output vectors; and
generating an output electrical signal based on the combined first and second output vectors.
2. The method of claim 1 , wherein combining comprises summing.
3. The method of claim 1 , wherein combining comprises differencing.
4. The method of claim 1 , wherein enhancing is conducted for phase difference values other than 0 degrees.
5. The method of claim 1 , wherein enhancing is conducted asymmetrically about a selected non-enhancement phase difference angle.
6. The method of claim 1 , further including applying sensitivity matching to accommodate device and/or signal mismatch in the system.
7. The method of claim 6 , wherein the sensitivity matching is based on a mathematical mean determination selected from the set of: arithmetic mean, geometric mean, harmonic mean and, a root-mean-square (rms), determinations.
8. A method for improving noise discrimination in a system having a plurality of sensors each configured to generate an input signal representable by an input vector having a phase component and a magnitude component, the plurality of sensors arranged to have an on-axis direction, the method comprising:
generating an input electrical signal from each of the plurality of sensors;
processing the input electrical signals from the plurality of sensors, said processing including:
using the input electrical signals from a first pair of sensors to obtain a coarse vector phase difference corresponding to a coarse measurement of an angle of arrival of a signal input source relative to the on-axis direction;
using the input electrical signals from a second pair of sensors to obtain a fine vector phase difference corresponding to a fine measurement of the angle of arrival of the signal input source;
generating an attenuation factor as a function of the coarse and fine vector phase differences;
combining the input vectors corresponding the second pair of sensors to obtain output vector; and
attenuating the output vector by the attenuation factor; and
generating an output electrical signal based on the attenuated output vector.
9. The method of claim 8 , wherein combining comprises differencing.
10. The method of claim 8 , wherein combining comprises summing.
11. The method of claim 10 , wherein the sensors are arranged in a two-dimension array.