Test and Development of High Data Rate Millimeter Wave Data Links Over Low Elevation Paths for Physical Security Systems

摘要

This report documents testing of a millimeter wave data link for its applicability to physical security systems. Propagation measurements were made at 27.3 GHz and 60 GHz. The feasibility of using these data links for high speed (1.5 Mbps tested) data transmission over low elevation transmission paths was established. Tests were conducted at Eglin Air Force Base (AFB), Davis Monthan AFB, and Minot AFB. The longest path over land tested was 9.6 km at 27.3 GHz. A 10.8 km path was tested over Choctawhatchee Bay, also at 27.3 GHz. Signal strength, weather conditions, and received test data and error statistics were collected simultaneously during the tests. Monthly and bimonthly averages of received power and weather conditions were computed from the measurements and showed seasonal variability at all three of the test sites. Histograms of received power, also generated from the test data, showed considerable variation on a monthly and bimonthly basis. In all cases, a high degree of reliability was observed with percent error free times ranging from 99.5% to 99.8%. The longest observation time was over 9000 hr at Davis Monthan AFB. Important observations of signal fluctuations caused by boundary effects of the terrain and the objects in or near the propagation path were made. These data should assist users in deployment of the data links, especially when using low elevation transmission paths for long distance signal transmission.