Applications with a non-cooperative Target

While appli­ca­tions with coop­er­a­tive tar­gets are of sig­nif­i­cant inter­est to Nutron­ics, Inc. and our sys­tems devel­oped for appli­ca­tions with coop­er­a­tive tar­gets form the basis of all of NAO Sys­tems tech­nol­ogy solu­tions, the area that has been our pri­mary research and devel­op­ment focus has been to develop and demon­strate a solu­tion to the prob­lem of com­pen­sa­tion in the pres­ence of branch points in the phase func­tion when the Rytov Num­ber exceeds 0.2 with non-cooperative tar­gets.  We largely con­sider the prob­lem of com­pen­sa­tion with coop­er­a­tive tar­gets in this regime “solved” for roughly 10 years with the recog­ni­tion of the supe­ri­or­ity of inter­fer­o­met­ric based wave­front sen­sors such as the Point Dif­frac­tion Inter­fer­om­e­ter (PDI) or Self-Referencing Inter­fer­om­e­ter (SRI).  The fact that these sen­sors have per­for­mance that is invari­ant with scin­til­la­tion defined a clear devel­op­ment path, and the sub­se­quent research and devel­op­ment lead­ing to our core prod­uct line fol­lowed a nat­ural and log­i­cal path .  In con­trast, devel­op­ment of a solu­tion path for the strong scin­til­la­tion regime with non-cooperative tar­gets has been far from straight­for­ward and has defined the NAO Sys­tems Imper­a­tive.

Nutron­ics, Inc. pro­vides Hart­mann sen­sor based AO sys­tems for the weak scin­til­la­tion regime (when the Rytov Num­ber is less than 0.2) and has devel­oped a bread­board lab­o­ra­tory demon­stra­tion of the Adap­tive Tac­ti­cal Laser Sys­tem (ATLAS) for oper­a­tion in the strong scin­til­la­tion regime (when Rytov Num­ber is greater than 0.2). These sys­tems usu­ally involve rea­son­ably high power lev­els and will invari­ably need to be cus­tomized to the appli­ca­tion of inter­est and Nutron­ics can dis­cuss cus­tomer require­ments on a case by case basis.

ATLAS is an inno­v­a­tive vari­a­tion of a com­pen­sated bea­con adap­tive optics (CBAO) sys­tem.  As dis­cussed in the NAO Sys­tem Imper­a­tive, CBAO sys­tems are not ensured to con­verge to a focused spot on the tar­get, as illus­trated in Fig­ure 1.

Fig­ure 1: AO com­pen­sa­tion, even when the bea­con laser is pre-compensated by the AO sys­tem to pro­vide bet­ter focus­ing of the beam on the tar­get is not effec­tive when the Rytov Num­ber exceeds 0.2 and in par­tic­u­lar is very poor in the Deep Tur­bu­lence regime when the Rytov Num­ber exceeds 1.0.

In con­trast, as illus­trated in Fig­ure 2, Nutron­ics, Inc.’s ATLAS beam con­trol sys­tem achieves per­for­mance com­pa­ra­ble to that of a point source bea­con, even in Deep Tur­bu­lence con­di­tions. Per­for­mance of a Hart­mann sen­sor based sys­tem is sig­nif­i­cantly worse than that for ATLAS. ATLAS does not uti­lize Target-In-the-Loop (TIL) meth­ods such as multi-dither or sto­chas­tic par­al­lel gra­di­ent descent and as such does not suf­fer from time of flight data latency. This allows ATLAS to be com­pat­i­ble with high tem­po­ral and spa­tial band­width oper­a­tion – both crit­i­cal for the next gen­er­a­tion of appli­ca­tions of AO in demand­ing tur­bu­lence conditions.

Fig­ure 2: Wave opti­cal sim­u­la­tion based inves­ti­ga­tion of ATLAS with Rytov Num­ber = 1.15 and D/rο = 13.1. ATLAS per­for­mance is pre­dicted to be sig­nif­i­cantly bet­ter than per­for­mance with a Hart­mann sen­sor and has per­for­mance nearly equiv­a­lent to that of a point source bea­con based system.

As illus­trated in Fig­ure  3, Nutron­ics, Inc. has demon­strated ATLAS beam con­trol in the lab­o­ra­tory with sim­u­lated atmos­pheric turbulence.

Fig­ure 3: ATLAS Lab­o­ra­tory Demon­stra­tion in severe tur­bu­lence con­di­tions with Rytov Num­ber = 1.00 and D/rο = 7.52.  The upper images of the laser on the tar­get include both the Track Illu­mi­na­tor (TILL) and the Sim­u­lated High Energy Laser (SHEL) on the reflexite-augmented tar­get while the lower images include only the SHEL to clearly indi­cate the effec­tive­ness of compensation.

While ATLAS tech­nol­ogy is just get­ting off the ground, please give us a call at 303−530−2002 or Email at jbarchers@naosystems.com and we will be happy to dis­cuss your appli­ca­tion and needs.  Many appli­ca­tions are well served by a more straight­for­ward and lower cost Hart­mann sen­sor based AO sys­tem and such sys­tems can be offered as minor vari­a­tions on our stan­dard products.

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