Apparatus and method for determining angles-of-arrival and polarization of incoming RF signals

A method for determining angles-of-arrival and polarization states of a plurality of incoming electromagnetic waves comprising the steps of:

• (a) converting said plurality of incoming electromagnetic waves into voltages with an antenna array comprising a plurality of RF sensing elements of differing substantially known polarization orientations;
• (b) electrically and switchably conducting said voltages from a plurality of said RF sensing elements to a receiver comprising at least three channels for receiving said produced voltages with an antenna selection network means;
• said antenna selection network means providing at least three output signals;
• (c) determining signal power of said voltages of said plurality of incoming RF signals as produced by said receiver;
• (d) determining frequencies of said sensed incoming RF signals;
• (e) determining phase differences of said sensed incoming RF signals as produced by said receiver;
• (f) determining corrections to said phase differences of said sensed incoming RF signals from said signal power of said voltages by first determining the coefficients a, b, and c as defined by:
• ##EQU5## and then determining said corrections directly as defined by:
• ##EQU6## (g) correcting said phase differences with said corrections with at least one summing junction;
• and
• (h) resolving angular ambiguities with said frequencies of said sensed incoming RF signals and the corrected phase differences
• whereby said angles-of-arrival and polarization of incoming RF signals are determined.

An improved method for determining angles-of-arrival and polarization states of a plurality of incoming electromagnetic waves of the type wherein said plurality of incoming electromagnetic waves are converted into voltages with an antenna array of the type wherein a plurality of RF sensing elements of differing substantially known polarization orientations are arranged in conformal rings, said voltages are electrically and switchably conducted from a plurality of said RF sensing elements to a receiver comprising at least three channels for receiving said produced voltages with an antenna element selection network providing at least three output signals, signal power and frequency of said voltages of said plurality of incoming RF signals and relative phase are determined by differencing selected receiver channels within said receiver, and angular ambiguities are resolved, the improvement comprising:

• (a) determining corrections to said phase differences of said sensed incoming RF signals from said signal power of said voltages and known antenna element orientations by first determining coefficients a, b and c according to:
• ##EQU7## and then determining the corrections according to:
• ##EQU8## (b) correcting said phase differences with said corrections with at least one summing junction prior to resolving angular ambiguities with said frequencies of said sensed incoming RF signals and the corrected phase differences
• whereby said angles-of-arrival and polarization of incoming RF signals are determined.

An apparatus for determining angles-of-arrival and polarization states of a plurality of incoming electromagnetic waves comprising:

• (a) an antenna element selection network for electrically and switchably conducting said plurality of incoming electromagnetic waves as voltages to a receiver comprising at least three channels for receiving said plurality of incoming electromagnetic waves as voltages;
• said antenna element selection network providing at least three output signals;
• (b) at least three square law detectors wherein each channel for receiving transmits to a unique member of said at least three square law detectors for determining signal power of said voltages of said plurality of incoming electromagnetic waves as produced by said receiver;
• (c) a circuit for time-based differencing of said plurality of incoming RF signals as conducted within at least one channel of said receiver for determining frequencies of said plurality of incoming electromagnetic waves;
• (d) a plurality of differencing junctions for determining phase differences of said plurality of incoming electromagnetic waves as produced by at least three receiver channels within said receiver;
• (e) processing means for determining corrections to said phase differences of said plurality of incoming electromagnetic waves from said signal power of said voltages by first determining coefficients a, b and c from said signal power and known antenna element orientations according to:
• ##EQU9## and then determining the corrections according to:
• ##EQU10## (f) at least one summing junction for correcting said phase differences with said corrections;
• and processing means for resolving angular ambiguities with said frequencies of said plurality of incoming electromagnetic waves and the corrected phase differences
• whereby said angles-of-arrival and polarization of incoming electromagnetic waves are determined.