Advanced Propagation Model (APM) Version 2.1.04 Computer Software Configuration Item (CSCI) Documents

Barrios, A. E.; Patterson, W. L.; Sprague, R. A.

doi:10.21236/ada464098

Cited by 15 publications

(23 citation statements)

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“…3 applies (22) Table 3) with radiation boundary condition assured through LTBC and NTBC application to the upper computational window boundary ( = 500 m), respectively. The profile from Table 3 0 , horizontal polarization, perfectly conducting smooth sea surface, and fixed height for the receiver z r =20 m. The computation is based on the APM [73]. Figure 3 (a) shows comparison between PL variations obtained for Mprofiles based on monthly mean values of the surface-duct parameters.…”

Section: Resultsmentioning

confidence: 99%

“…4 and (16) see [80]), vertical polarization with surface impedance characteristics calculated as a function of frequency in accordance with [123]. The computation is based on the APM [73]. Close to the sea surface, Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The RT is used in the case of evaporation duct, whereas SE is better suited for terrain applications; see the discussion on the properties of those methods in Kuttler and Dockery [69], Kuttler and Janaswamy [70], and Dockery et al [72]. The littoral zone includes both variable terrain and ducting and obtaining α for this scenario requires combination of both SE and RT [72,73]. In Barrios [45] the accounting for larger scale roughness (i.e., the terrain irregularities) with the PE method is done (for horizontal polarization and boundary condition for perfectly reflecting surface) by applying a general coordinate transformation [74] that flattens the surface elevations and introduces an additional term, responsible for the terrain effects, in the modified refractive index.…”

Section: Ssf Solution To the Pementioning

confidence: 99%

“…As it has been mentioned, the sophisticated ray methods (GTD, UTD (Uniform Theory of Diffraction)) and normalmodes methods (or hybrid combinations of them), which overcome the difficulties experienced by the simple ray theory in complex propagation environments (caustics, shadow zones, ducted propagation), are not easy to include in routine calculations. The great flexibility demonstrated by the PE has turned its simplest form (1) into the preferred technique for solving tropospheric propagation problems in a number of thoroughly validated and practically applied radiowave propagation assessment tools as: VTRPE (Variable Terrain Radio Parabolic Equation, solution of (1) based on SSF) [94], PCPEM (PC Parabolic Equation Model, SSF based) [37], TPEM (Terrain Parabolic Equation Model, uses SSF) [45], TER-PEM (TERrain Parabolic Equation Model, successor of PCPEM, combines PE and ray-trace techniques) [95], TEMPER (Tropospheric Electromagnetic Parabolic Equation Routine, based on DMFT) [69], [72], APM (Advanced Propagation Model, hybrid model that uses ray optics and DMFT-based PE) [73], PREDEM (PREdiction of ElectroMagnetic Detection) [96], AREPS (Advanced Refractive Effects Prediction System) [97]. Some of the limitations of this widely spread modeling of the 3D environment with 2D PE are discussed below.…”

Section: Validation Of the Pe And Limitations Of 2d Pementioning

confidence: 99%

“…The physics behind this profile, based on the Monin-Obukhov similarity theory, is explained elsewhere [7,108,109]. As indicated by Paulus and Anderson [111], (20) is a good practical approximation to the average M( ) profile, and has been widely used as input to the PE propagation model applied under evaporation duct conditions [27,33,40,73,97,[111][112][113][114][115]. Equation (20), however, has been obtained assuming thermally neutral troposphere stratification and does not account for the tropospheric stability effects on the M profile [7,29,33].…”

Section: Modeling Of the Environmentmentioning

confidence: 99%

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Brief review on PE method application to propagation channel modeling in sea environment

Sirkova

2011

Open Engineering

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This work provides an introduction to one of the most widely used advanced methods for wave propagation modeling, the Parabolic Equation (PE) method, with emphasis on its application to tropospheric radio propagation in coastal and maritime regions. The assumptions of the derivation, the advantages and drawbacks of the PE, the numerical methods for solving it, and the boundary and initial conditions for its application to the tropospheric propagation problem are briefly discussed. More details are given for the split-step Fourier-transform (SSF) solution of the PE. The environmental input to the PE, the methods for tropospheric refractivity profiling, their accuracy, limitations, and the average refractivity modeling are also summarized. The reported results illustrate the application of finite element (FE) based and SSF-based solutions of the PE for one of the most difficult to treat propagation mechanisms, yet of great significance for the performance of radars and communications links working in coastal and maritime zones -the tropospheric ducting mechanism. Recent achievements, some unresolved issues and ongoing developments related to further improvements of the PE method application to the propagation channel modeling in sea environment are highlighted.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Ssf Solution To the Pementioning

confidence: 99%

Section: Validation Of the Pe And Limitations Of 2d Pementioning

confidence: 99%

Section: Modeling Of the Environmentmentioning

confidence: 99%

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Brief review on PE method application to propagation channel modeling in sea environment

Sirkova

2011

Open Engineering

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Estimation of radio refractivity using a multiple angle clutter model

Karimian¹,

Yardim²,

Hodgkiss³

et al. 2012

Radio Science

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[1] The common occurrence of a marine boundary layer in coastal regions can affect radio wave propagation significantly. Refractivity from clutter (RFC) techniques are aimed at estimating the refractivity profile of the ambient environment based on the received radar clutter. While most previous RFC work has not considered the dependence of RFC inversions on a variable grazing angle, this study investigates incorporation of the grazing angle information into the clutter model. A newly proposed clutter model based on multiple incident angles at each range is used here. The inversion performance of the multiple angle clutter model is compared to that of other models. Synthetic examples of a range-independent surface-based duct and a range-dependent evaporation duct are investigated for a S-band radar. Finally, a comparison of inversions on one set of experimental measurements from the SPANDAR 1998 data set is provided, using single and multiple grazing angle clutter models, and the previously used model based on grazing angle independent sea surface reflectivity.

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Refractivity estimation from sea clutter: An invited review

et al. 2011

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[1] Non-standard radio wave propagation in the atmosphere is caused by anomalous changes of the atmospheric refractivity index. In recent years, refractivity from clutter (RFC) has been an active field of research to complement traditional ways of measuring the refractivity profile in maritime environments which rely on direct sensing of the environmental parameters. Higher temporal and spatial resolution of the refractivity profile, together with a lower cost and convenience of operations have been the promising factors that brought RFC under consideration. Presented is an overview of the basic concepts, research and achievements in the field of RFC. Topics that require more attention in future studies also are discussed.

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Advanced Propagation Model (APM) Version 2.1.04 Computer Software Configuration Item (CSCI) Documents

Cited by 15 publications

References 1 publication

Brief review on PE method application to propagation channel modeling in sea environment

Brief review on PE method application to propagation channel modeling in sea environment

Estimation of radio refractivity using a multiple angle clutter model

Refractivity estimation from sea clutter: An invited review

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