REVIEW  QUESTIONS Q8.    What is the purpose of the COVER program? Q9.    What are the limitations of the SSP program? Q10.   What is the major software advantage with the TESS-NC Transition as compared to the TESS (3)? Q11.   Which  government  environmental  software programs are provided with the TESS-NC? Q12.   What is the purpose of the TESS-NC Unix-based workstation? REFRACTIVE  EFFECTS  PREDICTION PROGRAMS LEARNING  OBJECTIVES:  Identify   the purpose  of  refractive  effects  prediction programs. Identify  the  refractive  effects displays  available  with  the  Integrated Refractive Effects Prediction System (REPS) and  the  Advanced  Refractive  Environmental Prediction  System  (AREPS).  Describe  the major advantages of AREPS. Refractive   effects   prediction   programs   are designed to provide Aerographer’s Mates with the capability of assessing the refractive effects upon naval surveillance,  communications,  electronic  warfare,  and weapon-guidance  systems.  Either  historical  or  real- time  upper-air  sounding  data  is  used  as  input. INTEGRATED  REFRACTIVE  EFFECTS PREDICTION SYSTEM (IREPS) The first refractive assessment software program was  the  Integrated  Refractive  Effects  Prediction  System (IREPS)  developed  in  the  late  1970s.  IREPS  is designed for use over open ocean areas only. The program assumes the homogeneity of the atmosphere (single airmass) based on the input of a single upper-air sounding.  Output  options  include  various  refractive effects products such as electromagnetic propagation conditions summaries (PCS), radar coverage display diagrams  (COVER),  path-loss  versus  range  displays (LOSS), surface-search radar range tables (SSR), and Electronic Support Measures (ESM) radar intercept- range tables. The applications and limitations of these programs were covered with TESS (3) in the previous section. Although IREPS is resident software on TESS (3), it is no longer issued as a stand-alone program. In addition, most of the products produced by IREPS have been incorporated into GFMPL. ADVANCED REFRACTIVE ENVIRONMENTAL  PREDICTION  SYSTEM (AREPS) The most current refractive effects assessment program  is  the  Advanced  Refractive  Environmental Prediction   System   (AREPS).   AREPS   computes basically the same refractive tactical decision aids as IREPS.  However,  AREPS  uses  a  more  advanced prediction  model  that  produces  more  accurate  data.  The most significant advantage of AREPS is that it can produce refractive effects predictions over land using terrain data obtained from either the National Imagery and Mapping Agency (NIMA) or the users own sources. In  addition,  AREPS  is  able  to  evaluate  range-dependent scenarios, and can also compute radar detection ranges for  multiple  bearings  simultaneously.  As  of  this writing,  users  must  build  their  own  electromagnetic riles as there is no electromagnetic data base provided with the program. Figure 2-2 is an example of an AREPS radar coverage diagram. The AREPS User’s Manual,  SSC  San  Diego  Technical  Document  3028 provides a detailed description of the AREPS program. AREPS is designed to run using Windows 95 or Windows NT and is normally obtained as part of the GFMPL NT package. You can also down- load  the  AREPS  program  and  the  AREPS  man- u a l    f r o m    t h e    S P A W A R S    w e b s i t e    a t : http://sunspot.spawar.navy.mil.  CD-ROM  versions  of AREPS are available from SPAWARS on a request- only basis. REVIEW  QUESTIONS Q13.  What  is  the  purpose  of  refractive  effects prediction  programs? Q14.    What is the most significant advantage of AREPS over IREPS? ELECTRO-OPTICAL  TACTICAL DECISION AID (EOTDA) LEARNING  OBJECTIVES:  Define  the  term Electra-Optics. Identify the purpose of the Electra-Optical   Decision   Aid   (EOTDA) program. Recognize  the  output  options available from the EOTDA program. 2-12