Publications

This report presents work done during phase 3 of the US national Microwave Landing System (MLS) program toward developing a computer simulation model of the MLS multipath effects, the experimental validation ot the model, and the application of the model to investigate multipath performance of ICAO proposals for the new approach and landing guidance system. The first two volumes of the report presented an overview of the simulation effort as well as describing in detail the propagation and MLS technique mathematical models and their validation by comparison with experimental data. In this volume, we describe the results of comparative simulations for the various MLS techniques in various scenarios and analyze in detail certain multipath performance features which were found to be significant in the scenario simulations. Simulation results are presented for several scenarios, and shadowing of the MLS azimuth by taxiing and overflying aircraft is analyzed. The remainder of the report focuses onmultipath performance factors specific to various individual techniques. These include: (1) the effects of angle data outlier tests and filtering in the TRSB receivers, (2) the effects on the DMLS system due to receiver AGC, receiver motion-induced Doppler shifts, and the use of commutated reference systems, and (3) acquisition/validation algorithms for all three techniques. The report concludes with a summary and suggestions for future work. Part I of this volume consists of Chapters I through IV; Part II contains Chapters V through VIII and the Appendices.

This report presents work done during phase 3 of the US national Microwave Landing System (MLS) program toward developing a computer simulation model of the MLS multipath effects, the experimental validation ot the model, and the application of the model to investigate multipath performance of ICAO proposals for the new approach and landing guidance system. The first two volumes of the report presented an overview of the simulation effort as well as describing in detail the propagation and MLS technique mathematical models and their validation by comparison with experimental data. In this volume, we describe the results of comparative simulations for the various MLS techniques in various scenarios and analyze in detail certain multipath performance features which were found to be significant in the scenario simulations. Simulation results are presented for several scenarios, and shadowing of the MLS azimuth by taxiing and overflying aircraft is analyzed. The remainder of the report focuses on multipath performance factors specific to various individual techniques. These include: (1) the effects of angle data outlier tests and filtering in the TRSB receivers, (2) the effects on the DMLS system due to receiver AGC, receiver motion-induced Doppler shifts, and the use of commutated reference systems, and (3) acquisition/validation algorithms for all three techniques. The report concludes with a summary and suggestions for future work. Part I of this volume consists of Chapters I through IV; Part II contains Chapters V through VIII and the Appendices.

This report presents work done during phase 3 of the US national Microwave Landing System (MLS) program toward developing a computer simulation model of the MLS multipath effects, the experimental validation ot the model, and the application of the model to investigate multipath performance of ICAO proposals for the new approach and landing guidance system. This second volume of the report presents the mathematical models and validation data for the MLS techniques which were assessed in detail by the All Weather Operations Panel of the Interational Civil Aviation Organization. The specific techniques modeled are: 1. The Time Reference Scanning Beam (TRSB) system proposed by the United States (US) and Australia, with prime emphasis on the US equipment implementation and field test data, 2. the Doppler scan (DMLS) proposed by the United Kingdom, and 3. the DME Based Landing System (DLS) proposed by the Federal Republic of Germany.

This report presents work done during phase 3 of the US national Microwave Landing System (MLS) program toward developing a computer simulation model of the MLS multipath effects, the experimental validation ot the model, and the application of the model to investigate multipath performance of ICAO proposals for the new approach and landing guidance system. This first volume of the report presents an overview of the overall simulation results as well as a description of the refined mathematical models and validation of the propagation portion of the simulation. Specific propagation topics include: 1) preliminary results for validation of models for reflections from rough and/or rising terrain based on L-band field data. 2) validation of the models for building reflections based on field measurements at a number of operational airports. 3) validation and refinement of the models for angle guidance system shadowing by obstacles such as buildings and other objects.