Bae Systems Information and Electronic Systems Integration Inc.

Wisterium Development LLC

Thomas R Vaccaro

Court E Rossman

Allan M Kabel

Ryan E Long

Norman D Paul

Costin Barbu

A method, system, and computer program are described for identifying the presence of narrowband signals within a wide instantaneous bandwidth by exploiting the spatial diversity of the received signals using an array aperture to provide detection capability. For example, the method includes receiving and channelizing digitized signals into signals with a narrow bandwidth of interest. The method further includes estimating covariance matrices associated with the signals, determining a set of Eigenvalues for the covariance matrices, and analyzing each Eigenvalue to determine a rank change estimate. The method further includes identifying one or more of the signals that have a positive rank change estimate, computing a beam forming weight and direction estimate for each signal that has a positive rank change estimate, and outputting an indication of the signals that have a positive rank change estimate including one or more of fine timing information, the beamforming weights, and the direction estimate.

Spatial energy rank detector and high-speed alarm

A system and method for rank estimation of electromagnetic emitters is provided. One exemplary feature of the system and method includes the use of a Fixed Sigma Gaussian Mixture Model (FSGMM) to determine a rank estimation of electromagnetic emitters. Another exemplary feature of the system and method includes the use of a Gaussian Mixture Model (GMM) clustering approach in conjunction with an Akaike Criterion Information (AIC) to determine a number of clusters and associated statistics of emitters.

System and method for rank estimation of electromagnetic emitters

A system and method for rank estimation of electromagnetic emitters is provided. One aspect of the disclosure provides creating a graph of angles of arrival (AoAs) versus range and using a polynomial curve fit against the graph to determine a rank estimation of electromagnetic emitters. Another aspect of the disclosure provides using a search over parameters of the multiple polynomial curve fits, for each hypothesized rank, to optimize the rank estimation results. This search may be a greedy search to improve speed of convergence. Another aspect of the disclosure provides a metric 'score' to select the highest probability rank (number of emitters) based on the agreement between the multiple polynomial curve fits and residual AoA errors.

A channelized filter design for partial band reconstruction having high dynamic range requirements. The analysis filter and synthesis filter constraints permit high performance signal detection with an alias free signal recombination capability for signals that span multiple frequency bins. The filter bank allows the use of a single wideband asset to provide for data channelized for detection processing with the ability to recombine one or more adjacent frequency bins into a wider bandwidth baseband time domain data stream suitable for exploitation processing. Use of an efficient partial band reconstruction mechanism allows signal reconstruction using only the frequency subchannels that pertain to the signal of interest that is to be copied. The filter design mechanism separates the specification of the analysis filter to support signal detection in environments of high dynamic range. The signal reconstruction (synthesis) filter uses fewer bins and allows a higher order filter.

Partial band reconstruction of frequency channelized filters

A system is provided for assisting in the detection and tracking of narrowband signals arriving at an antenna array operating over a wide detection bandwidth and in a crowded RF environment. Since the nature of the detection mission is constrained to be a general search, the system does not attempt to detect signals of interest via matched filtering mechanisms (i.e. training sets), but exploits general properties such as power, frequency, time and angle of arrival. For the purposes of providing sufficient Frequency/Time resolution as well as to avoid array overloading in the detection process, the digitized wideband streaming data is frequency channelized using a sufficiently high revisit rate for the signal set of interest, constrained by the required feature detection accuracy or environment adaption rates. Within each frequency subchannel, efficient array signal subspace tracking techniques are used to separate and track spatially separated cochannel signals. Subspace tracking allows the efficient update of the signal subspace, useful for direction finding and copy applications, as well as determining the number of signals present in a frequency channel. Since the frequency channelization of the detection system may not match that of the detected signal, the combination of Time/Frequency/Space information is used to cluster or group frequency subchannels and provide a higher degree of signal detection capability with an increased robustness against false signal detections.

Growing community of inventors

Hudson, NH, United States of America

Thomas R Vaccaro