公开(公告)号：US10277320B1

公开(公告)日：2019-04-30

申请号：US15968083

申请日：2018-05-01

Applicant: BAE Systems Information and Electronic Systems Integration Inc.

Inventor： David A Haessig, Jr. ,  Dennis P Bowler ,  Robert T Carlson

IPC: H04B10/118 ,  H04B10/50

Abstract: A disclosed apparatus and method verify whether a hot spot within a scene is a valid laser-com signal, and further identify laser-com signals of interest. An extended Kalman filter (EKF) is applied to a received signal or beacon to detect whether it is modulated according to a square wave or other expected amplitude modulation pattern. Embodiments further determine whether the modulation frequency matches a signal or beacon of interest. In embodiments, a plurality of indexed EKF's are “tuned” to different modulation frequencies, and are used to identify a beacon's modulation frequency index. Where each EKF is required to compute amplitude and phase partial derivatives of the observation vector, the amplitude partials can be calculated according to the expected modulation pattern, and the phase partials can be calculated using a truncated Fourier or step-wise approximation of the expected modulation pattern. Embodiments further assume a time-invariant covariance matrix.

公开(公告)号：US10236980B1

公开(公告)日：2019-03-19

申请号：US16002052

申请日：2018-06-07

Applicant: BAE Systems Information and Electronic Systems Integration Inc.

Inventor： Robert T Carlson ,  Dennis P Bowler ,  David C Donarski ,  David A Haessig, Jr. ,  Stuart M Lopata ,  Dale A Rickard

IPC: H04B10/112 ,  H04B10/118 ,  G06K9/62 ,  H04B10/079 ,  G06T7/13

Abstract: A disclosed apparatus and method detect light source “hotspots” and recognize laser communication signals within a scene, while minimizing repeat consideration of previously detected light sources. Local maxima are identified in pixel frames from a focal plane array (FPA), and compared with a table of previous detections. FPA frames can be used directly for hotspot detection, or successive FPA frames can be subtracted for edge detection. Most recent detection frame numbers, coordinates, signal values, and/or other information can be updated in the table upon repeat detection of a hotspot. Source identifying information can be included in the table for entries that are identified as laser communication signals. Source identifying features can be evaluated so that only signals of interest are saved in the table. Hotspots that remain undetected after a designated number of frames can be deleted from the table.

公开(公告)号：US10230467B1

公开(公告)日：2019-03-12

申请号：US16000991

申请日：2018-06-06

Applicant: BAE Systems Information and Electronic Systems Integration Inc.

Inventor： David A Haessig, Jr. ,  Dennis P Bowler ,  Robert T Carlson

IPC: H04B10/118 ,  H04B10/67 ,  H04B10/112

Abstract: An apparatus and method for tracking a laser communication signal of interest incident on a focal plane array (FPA) identifies a plurality of “hotspots” in a scene of interest, and aligns a hotspot that is a signal of interest (SOI) or beacon component thereof with the FPA. Hotspot centroids can be estimated within a fraction of an FPA pixel by considering squares of four pixels and comparing their signal amplitudes. A multi-spot calculation is used to improve the position estimates of all of the hotspots by applying a Kalman filter to the hotspot position data and assuming that the relative hotspots positions are fixed. The calculation is periodically repeated to enable tracking of the SOI. Amplitude variability of the hotspots is accommodated by weighting the hotspot contributions according to their intensities. In embodiments, estimation error of the SOI centroid is less than a smallest dimension of the FPA pixels.