Second generation of AVTIS FMCW millimeter wave radars for mapping volcanic terrain

The second generation AVTIS ground-based millimeter wave instruments designed for monitoring topography of volcanic lava domes are solid state 94 GHz FMCW rastered, real beam radars operating at ranges of up to ~7 km with a range resolution of ~2.5 m. Operating ten times faster than the prototype with reduced power consumption suitable for battery powered portable use as well as installation at a telemetered site under solar power, we examine their performance as tools for monitoring topography over time and report on the operational statistics both as a radar sensor and as a means of generating digital elevation maps.Publisher PD

Multipath Interferences in Ground-Based Radar Data: A Case Study

Multipath interference can occur in ground-based radar data acquired with systems with a large antenna beam width in elevation in an upward looking geometry, where the observation area and the radar are separated by a reflective surface. Radiation reflected at this surface forms a coherent overlay with the direct image of the observation area and appears as a fringe-like pattern in the data. This deteriorates the phase and intensity data and therefore can pose a considerable disadvantage to many ground-based radar measurement campaigns. This poses a problem for physical parameter retrieval from backscatter intensity and polarimetric data, absolute and relative calibration on corner reflectors, the generation of digital elevation models from interferograms and in the case of a variable reflective surface, differential interferometry. The main parameters controlling the interference pattern are the vertical distance between the radar antennas and the reflective surface, and the reflectivity of this surface. We used datasets acquired in two different locations under changing conditions as well as a model to constrain and fully understand the phenomenon. To avoid data deterioration in test sites prone to multipath interference, we tested a shielding of the antennas preventing the radar waves from illuminating the reflective surface. In our experiment, this strongly reduced but did not completely prevent the interference. We therefore recommend avoiding measurement geometries prone to multipath interferences

94 GHz Radar Backscatter Characteristics of Alpine Glacier Ice

Acknowledgments William D. Harcourt would like to thank PhD studentship funding from SAGES and EP281 SRC (grant number: EP/R513337/1). Funding for this study was obtained from the Scot282 tish Alliance for Geoscience, Environment and Society (SAGES) Small Grant Scheme. We would like to thank the staff at the Rhˆonegletscher Eisgrotte Cafe for enabling en284 trance to the field site and supporting the field activities, as well as the VAW Glaciol285 ogy Group and Glacier Monitoring in Switzerland groups for providing aerial photogram metry data over Rhˆonegletscher. Thanks also to Josu´e Gehring, Alexis Berne and Etienne Vignon for assisting with collection and delivery of our equipment at Ecole Polytechnique D´ed´erale de Lausanne (EPFL).Peer reviewedPublisher PD

Active microwave remote sensing of earth/land, chapter 2

Geoscience applications of active microwave remote sensing systems are examined. Major application areas for the system include: (1) exploration of petroleum, mineral, and ground water resources, (2) mapping surface and structural features, (3) terrain analysis, both morphometric and genetic, (4) application in civil works, and (5) application in the areas of earthquake prediction and crustal movements. Although the success of radar surveys has not been widely publicized, they have been used as a prime reconnaissance data base for mineral exploration and land-use evaluation in areas where photography cannot be obtained

Science exploration opportunities for manned missions to the Moon, Mars, Phobos, and an asteroid

Scientific exploration opportunities for human missions to the Moon, Phobos, Mars, and an asteroid are addressed. These planetary objects are of prime interest to scientists because they are the accessible, terresterial-like bodies most likely to be the next destinations for human missions beyond Earth orbit. Three categories of science opportunities are defined and discussed: target science, platform science, and cruise science. Target science is the study of the planetary object and its surroundings (including geological, biological, atmospheric, and fields and particle sciences) to determine the object's natural physical characteristics, planetological history, mode of origin, relation to possible extant or extinct like forms, surface environmental properties, resource potential, and suitability for human bases or outposts. Platform science takes advantage of the target body using it as a site for establishing laboratory facilities and observatories; and cruise science consists of studies conducted by the crew during the voyage to and from a target body. Generic and specific science opportunities for each target are summarized along with listings of strawman payloads, desired or required precursor information, priorities for initial scientific objectives, and candidate landing sites. An appendix details the potential use of the Moon for astronomical observatories and specialized observatories, and a bibliography compiles recent work on topics relating to human scientific exploration of the Moon, Phobos, Mars, and asteroids. It is concluded that there are a wide variety of scientific exploration opportunities that can be pursued during human missions to planetary targets but that more detailed studies and precursor unmanned missions should be carried out first