Prediction Of Radio Wave Propagation Loss On Irregular Terrain By Of Multi-Model Method Based On Digital Terrain Elavation Data

As the popularity of mobile electronic devices and radio waves of more and more widely used in the business, such as national defense, public safety, broadcasting, commercial and industrial communications, aeronautical and maritime communications, navigation and radiolocation as well as personal communications. Estimated calculation of radio wave propagation loss becomes increasingly important. Early people made a lot of classic radio wave propagation prediction models, such as: Durkin model, Longley-Rice model, Okumura model, Hata model, Lee model. But these models ignore the path of some of the specific terrain parameters, such as: barrier height, size and so the number of barriers and obstacles which directly affect the estimated accuracy of the results. With the development of geographic information systems to digitally record and store digital maps are readily available, including terrain elevation, topography and other radio wave propagation affect geographic information herein traditional radio wave propagation prediction model using geographic information systems, propagation prediction model based on DTED(digital Terrain Elevation Data) format digital maps were studied.In this theis, the main work are as following:First, The thesis complete the study of the DTED format digital map application in wave propagation path loss estimate computing problems. Use software to determine the propagation path based on latitude and longitude of the transmitting and receiving antennas, and propagation path interception of two-dimensional cross-section, discrete, export data to prepare for modeling.Second, this thesis studied a variety of propagation model given in Recommendation ITU, including sub-surface diffraction model, surface multipath interference sub-model, single-edged peak diffraction sub-model, multi-edge diffraction peak of sub-models, rounded peaks around shot sub-model, sub-model dual-path interference and atmospheric refraction effector model. And according to a variety of different topography corresponding to the digital map, analysis the conditions and propagation mechanisms that occurs when the wave propagation appears, these models were applied to establish local area sub-models of the terrain, this thesis complete model, computational propagation loss and authentication model combined with the digital map is correct.Third, this thesis proposed a combination of multiple sub-model method which is used to accurately predict the complex calculation of irregular wave propagation path loss topographic large scale. The combination of all combinations of conditions local area sub-models for three large-scale, complex irregular terrain, using the combination of multiple sub-model prediction calculation method for modeling wave propagation loss. The propagation path is divided on the insight area, diffraction and refraction zone. And based on antenna height, frequency, The three areas were calculated and analyzed.Fourth, compared with Longley-Rice method from the computational efficiency, accuracy of results, comparative analysis of the scope,the results show that this method can more accurately reflect the local terrain on the path loss Effect for complex terrain wave propagation path loss estimate calculation, higher computational efficiency.