US 12,216,198 B2
Complex recurrent neural network for Synthetic Aperture Radar (SAR) target recognition
Qin Jiang, Malibu, CA (US); David Wayne Payton, Malibu, CA (US); Soheil Kolouri, Agoura Hills, CA (US); Adour Vahe Kabakian, Monterey Park, CA (US); and Brian N. Limketkai, Santa Monica, CA (US)
Assigned to THE BOEING COMPANY, Arlington, VA (US)
Filed by The Boeing Company, Chicago, IL (US)
Filed on Nov. 23, 2021, as Appl. No. 17/456,345.
Claims priority of provisional application 63/135,553, filed on Jan. 8, 2021.
Prior Publication US 2022/0229173 A1, Jul. 21, 2022
Int. Cl. G01S 13/90 (2006.01)
CPC G01S 13/9011 (2013.01) [G01S 13/9088 (2019.05)] 21 Claims
OG exemplary drawing
 
1. A method, comprising:
receiving raw synthetic aperture radar (SAR) data associated with observed views of a scene, wherein the raw SAR data comprises information captured via an automatic target recognition (ATR) system having a SAR system;
radio frequency (RF) preprocessing the received raw SAR data to produce a processed raw SAR data which includes two-dimensional data that includes frequency band data and pulse domain data;
converting the processed raw SAR data to a complex SAR range profile data;
processing the complex SAR range profile data with a recurrent neural network (RNN) having RNN states; and
mapping the RNN states to a target class with a multi-layer linear network;
wherein the processed raw SAR data is represented by a two-dimensional array represented by PH(m,n), wherein m represents frequency band values of a row vector Pf of the frequency band data and n represents pulse domain values of a column vector Pr of the pulse domain data; and
wherein converting the processed raw SAR data to the complex SAR range profile data comprises:
determining a range profile vector rpr(m) defined by a relationship defined as

OG Complex Work Unit Math
where:
Pw(k) is derived from Pr(i)=PH(i,r),
M represents a maximal range bin that is determined by a number of sampling frequencies in the frequency band data; and
m represents range bins;
wherein the complex SAR range profile data is obtained based on the range profile vector rpr(m).