Propagation Models in AREPS

About AREPS
The Advanced Refractive Effects Prediction System (AREPS) program computes and displays a number of electromagnetic (EM) system performance assessment tactical decision aids. These are radar probability of detection, electronic surveillance measure (ESM) vulnerability, HF to EHF communications, simultaneous radar detection and ESM vulnerability, and surface-search detection ranges. All decision aids are displayed as functions of range, bearing, and or height. Detection probability, ESM vulnerability, and communications assessments are based on electromagnetic (EM) system parameters stored in a changeable database you maintain. Paths containing land features depend on terrain data either obtained from the National Geospatial-Intelligence Agency’s (NGA) Digital Terrain Elevation Data (DTED) or specified from your own source. Using a mouse or other pointing device, you may display many additional pieces of information, including height, range, latitude, and longitude from the decision aid’s geographical center, terrain elevations, and propagation loss values.


Propagation Models
AREPS contains several EM propagation models for applications at various frequencies. For frequencies of 2 MHz to 57 GHz, AREPS uses the Advanced Propagation Model (APM). APM is a hybrid model that uses the complimentary strengths of both ray optics and parabolic equation methods to construct a fast, but yet very accurate, composite model. Depending upon the requirements of the tactical decision aid, APM will run in several different modes. For the full hybrid mode, APM has proven to be much faster than PE models alone, with overall accuracy at least as good as the pure PE models. With its airborne sub-model, APM can solve problems for very high elevation angles, that PE methods would not normally be used. APM includes the ability to model absorption by oxygen and water vapor.
For HF sky wave communications, AREPS uses a HF model suite consisting of a fully 3-dimensional ionosphere raytrace model, an HF field strength model, and an HF noise model. In addition to these EM propagation models, AREPS may optionally use two internationally recognized ionosphere models, the Parameterized Ionospheric Model (PIM) and the International Reference Ionosphere.

My Remarks

• for more in formation visit site
  
• Currently using in US Force
• Continental scale operation
• DoD property not for sell
• APM source code is no longer available but they seem willing to provide, if we contract them