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Creating a Customizable and Reconfigurable Scaling Law Model Using Matlab

Creating a Customizable and Reconfigurable Scaling Law Model Using Matlab. Amy M. Ngwele For Directed Energy (DE) Systems Symposium 20 March 2007. Introduction. Alternate title – Modifications to SHaRE for increased customizability and reconfigurability

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Creating a Customizable and Reconfigurable Scaling Law Model Using Matlab

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  1. Creating a Customizable and Reconfigurable Scaling Law Model Using Matlab Amy M. Ngwele For Directed Energy (DE) Systems Symposium 20 March 2007

  2. Introduction • Alternate title – Modifications to SHaRE for increased customizability and reconfigurability • Methods could be implemented with other Matlab-based codes and possibly others • SHaRE stands for Scaling for High Energy Laser and Relay Engagement • SHaRE has been used to model strategic, tactical, ground-based, and maritime HEL systems with and without relays • Also employed to model imaging systems and novel AO concepts

  3. Outline • Brief introduction to SHaRE with overview of the modeling approach • Problem and solution • Outline original architecture of SHaRE and modifications made to increase extensibility • Various examples illustrating the new features

  4. SHaRE Modeling Approach • Each propagation link is specified separately • Of type “UPLINK”, “CROSSLINK”, or “TARGETLINK” • Link specification is established by calls to “LinkCase” including: • System parameters (P) • Link 3-D geometry (G) • Atmospheric model assumptions (Atm) • Links may be analyzed separately or in combination • Error terms are broken down link-by-link (LinkTerms) • Link ordering may affect evaluation of certain terms in error breakdown • Evaluation of target beam metrics may be accomplished for any valid combination of links • Permits quantification of intermediate results • Uplink, crosslink beam control (NPR, Strehl, jitter)

  5. Modes of Use • SHaRE has been developed as a MATLAB Toolbox • Most utility is realized when used from the MATLAB command line, in MATLAB scripts or functions, and with other toolboxes • Built-in functions provide a high level of abstraction • SHaRE has other interfacing options • GUI: Can be used to visualize results, alter scenario • Spreadsheet: M.S. Excel interfacing features are supported • MATLABExcel: Create Excel spreadsheet of MATLAB results • ExcelMATLAB: Create MATLAB script/inputs from Excel • ExcelMATLABExcel: Front-end for those who prefer Excel

  6. System Design Specifications Engagement-Tools Toolbox Target Model AtmTools Toolbox SHaRE Conceptual Model System and Link Parameters Propagation Characterization Link ErrorTerms Target Beam Metrics HEL Wavelength, HEL Power Tx/Rx OptLoss, Tx/Rx OptWFE, Tx/Rx ResBaseSigP/T, Tx/Rx Diameters, Tx/Rx TRK, Tx/Rx AO, Config … code: 'UA' type: 'UPLINK' ver: [1x6 struct] P: [1x1 struct] G: [1x1 struct] Targ: [1x1 struct] Atm: [1x1 struct] wavelength: 1.3150e-006 hp: 12192 ht: 21336 rd: 5.0000e+004 L: 5.0958e+004 vp: 230.0000 vt: 10 V_TTP: 7.7505 V_PTP: 178.0886 V_PTT: 1.1269 az: -0.8727 el: 0.1765 tia: -0.6840 LOSangle: 0.8856 Fresnel: 33.5769 Rytov: 0.0263 r0: 0.6794 theta0: 6.6449e-006 fG: 100.6872 fT: 17.6991 Nd: 0.8730 T.Loss.TxOptLoss: 0.9500 T.Loss.RxOptLoss: 0.9500 T.Loss.AtmTrans: 0.9929 T.Loss.NPR: 0.8711 T.Sh.TxOpticsWFE: 0.7602 T.Sh.RxOpticsWFE: 0.9843 T.Sh.ResAtm: 0.9719 T.Sh.DMfit: 0.9759 T.Sh.HiddenPhase: 1 T.Sh.PhaseOnly: 0.9659 T.Sh.HELBQ: 0.8264 T.Sh.ThermBloom: 0.9966 T.Sh.Diffract: 0.9079 T.sigP.TxResBase: 2.6117e-7 T.sigP.RxResBase: 0 T.sigP.ResAtm: 4.4060e-9 Ipk: 34.0203 IsigP: 6.0431e-007 IsigT: 6.0430e-007 Loss: 0.7806 S: 0.4265 Sh: 0.5763 sigHOP: 5.4494e-007 sigHOT: 5.4494e-007 sigP: 2.6121e-007 sigT: 2.6118e-007 Sj: 0.6954 P P = LinkParams Engagement Geometry Coordinates, RP, VP, RT, VT, TALO, EarthModel, EarthRadius Target Irradiance G Atmosphere Cn2, Temp, Wind, WindHeading, Ext, Abs, Scat,… Atm Target Info trackpt, BILLpt, HELpt, class, TargetRadius Targ C C = CaseStruct(P,G,Targ,Atm) T T = LinkTerms(C) M M = TargetBeamMetrics(T)

  7. Original Implementation • Complete control over how effects were combined to derive top-level beam metrics • Specification of a rollup function for TargetBeamMetrics • Several included with SHaRE, supports user-defined rollup functions • Some control over what effects were included • Ability to include custom error terms, effects typically not modeled • No thermal blooming? Remove absorption, scattering, and/or temperature from the Atm structure • No finite-bandwidth effects? Set bandwidths in the P structure to zero • Sometimes cumbersome to re-include effects • No control over how effects were computed • Function LinkTerms was a “black box” in which error terms were computed using what the authors considered to be the “best” method

  8. Desired Implementation • Wanted the ability to specify which effects to include and how included effects were to be computed • Do this without removing or modifying system parameters or atmospheric specification • Also wanted the user to be able to see how error terms were being computed

  9. Solution • Inclusion of link parameters • Use a link configuration structure to determine which effects get included and the methods for computing • Implementation also supports custom methods • User can write code for computation of any error term • May include and access additional system parameters not already existing in the system parameter structure • Functions for display of methods making error term calculation more transparent

  10. code: 'DEFAULT' ATM_Extinction: 'ANALYSIS' ATM_Turbulence: 'ANALYSIS' ATM_Dispersion: 'NONE' ATM_ThermalBlooming: 'ANALYSIS' HEL_Loss: 'NONE' HEL_Field: 'BUDGET' HEL_Disturbance: 'ANALYSIS' OPT_Loss: 'BUDGET' OPT_Field: 'BUDGET' OPT_Obscuration: 'ANALYSIS' OPT_Turret: 'NONE' AOS_Field: 'NONE' AOS_HiddenPhase: 'SCALING' AOS_PhaseOnly: 'SCALING' AOS_Noise: 'NONE' AOS_Fitting: 'SCALING' AOS_FiniteBW: 'ANALYSIS' AOS_ExtendedBeacon: 'NONE' AOS_Aniso: 'SCALING' TRK_Scint: 'NONE' TRK_Noise: 'NONE' TRK_FiniteBW: 'ANALYSIS' TRK_Aniso: 'SCALING' Each field in the configuration structure indicates modeling of a different effect. (Not all fields are shown) The value of the field indicates the method to be used in modeling Turbulence (ATM_Turbulence) is modeled using an ‘Analysis’ method ATM_Turbulence Transmission due to optics (OPT_Loss) uses a budgeted value in the P structure The function LinkConfig has several options for configuration Configuration Structure

  11. Error Term Methods • Function LinkMethods was written to be a database of all error term evaluation methods for different link types • Specify the link type (one of ‘TARGETLINK’, ‘UPLINK’ or ‘CROSSLINK’) and the desired error term configuration • Outputs are structures of evaluations to be computed first (First), intermediate evaluations (Link), and evaluations to be done last (Last). [First,Link,Last] = LinkMethods(LinkType,[Config])

  12. Each structure contains fields for different types of effects, classified based on the effect to irradiance on target. For example, First.Loss, Link.Loss, and Last.Loss contain evaluations for loss terms based on the input configuration. Each term is expressed as a cell array of strings to be evaluated within the function LinkTerms Error Term Evaluations First = Scaling: [1x1 struct] Loss: [1x1 struct] Sh: [1x1 struct] ShP: [1x1 struct] ShT: [1x1 struct] sigP: [1x1 struct] sigT: [1x1 struct] First.Loss = HELInjection: {[]} TxOptLoss: {'[Tx.OptLoss]'} Link.Loss AtmTrans: {'Transmission(Atm)'} NPR: {[]}

  13. PTarget PPlatform Config = Variable = Function = Operation First Merge Data Link LinkMethods Last LinkParams G Targ Atm P CaseStruct C Implementation Chart Added

  14. Add a custom error term to the parameter structure. When a value is specified for only one axis, the term is added in the other axis with a value of zero. Custom Error Term >> C = LinkCase('dt'); >> C.P.Tx.sigP.TrkJitter=0.5e-6; >> T = LinkTerms(C); >> T.sigP ResAtm: 4.9557e-007 TrkJitter: 5.0000e-007 TxResBase: 1.0000e-006 TiltAniso: 0 >> T.sigT ResAtm: 3.3114e-007 TrkJitter: 0 TxResBase: 1.0000e-006 TiltAniso: 0

  15. Custom Error Term >> C = LinkCase('da'); >> P = C.P; >> P.Tx.Sh.FocalAniso = 'FocalAnisoStrehl(C,400e3)'; >> C = CaseStruct(C,'P',P); >> T = LinkTerms(C); >> T.Sh.FocalAniso 0.2883 • Add a custom error term evaluation to the parameter structure

  16. Rules • Rules are outlined in the SHaRE users guide • The following variables are available in LinkTerms when methods are being evaluated: • T and the substructures of T, i. e. C, Scaling, Loss, Sh, ShP, ShT, sigP, and sigT • Substructures of C, i. e. G, P, Targ, and Atm • Substructures of P, i. e. Config, HEL, Tx, Rx, First, Link, and Last • Substructures of Tx (and Rx, if not empty), TxTRK, TxAO, RxTRK, and RxAO • Ti - an array of computed link terms structures from all previous links

  17. Rules (cont.) • The evaluation of error terms is done in the following order: • Methods contained in P.First • All methods and custom terms contained in P.HEL, P.Tx, and any user-added substructures, evaluated in the order that they appear in P • Methods in P.Link • Methods and custom terms in P.Rx, if the link is an UPLINK or CROSSLINK • Methods in P.Last • The final evaluation in the cell array of evaluations must be an assignment of the error term

  18. Custom Configuration >> Cfg = LinkConfig('default'); >> Cfg.AOS_FocAniso = {'[S,d0] = FocalAnisoStrehl(C,400e3);';... 'T.Scaling.LGSSectionSize = d0;';... 'S'; >> C = LinkCase('da','Config',Cfg); >> T = LinkTerms(C); >> T.Scaling.LGSSectionSize 1.3159 • Include effect of focal anisoplanatism as written and add the intermediate calculation of d0 to the scaling substructure of T.

  19. Custom Track Noise Model >> Cfg = LinkConfig('default'); >> Cfg.TRK_Noise = ... {'[sigP,sigT]=MyNoiseJitter([TxTRK.BW],[TxTRK.IFOV]);';... 'T = VaryStruct(T,''sigT.TrkNoise'',sigT);';... 'sigP'}; >> C = LinkCase('dt'); >> C.P.Tx.TRK.IFOV = 1e-6; • User has a function on their Matlab path called MyNoiseJitter that is a function of the bandwidth of the controller and the field of view of the camera • Write code to be evaluated and include IFOV in the system parameters since it is not a standard parameter

  20. Error Term Methods GUI

  21. Summary • SHaRE has always had an open and extensible architecture, but now that has been increased greatly • You can write your own functions to work with SHaRE and ATMTools • User now has much more control over the calculation of error terms in SHaRE • SHaRE has become a powerful and more universal scaling law

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