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Some problems in kinematic airborne laser survey

Al Bayari O.

Reports on Geodesy

2000

z. 8/54

105-113

Kinematic positioning is considered the most important factor to create a reliable DTM by Airborne laser scanning and it requires accurate and consistent base to aircraft vector throughout the survey. In Italy there are many interference signal problems that could cause the loss of GPS signal during the survey. A problem like that bas been faced during the Laser Scanning survey at Bracigliano landslide in south Italy. Actually, the high costs prevent the possibility to make experimental flights before laser scanning surveys, moreover the presence of interference could be irrelevant when kinematic ground survey is instead performed to check the area. In this work some studies of kinematic positioning in airborne laser scanning and the influence of the distance between reference and rover receivers on the obtained DTM have been ascertained. Finally the possibilities of integration of the DTM obtained in national reference systems have been discussed .

Evaluation of ionospheric effects on SAR interferometry in Antarctica

Al Bayari O.

Reports on Geodesy

2000

z. 8/54

24-31

The influence of atmospheric inhomegeneities on SAR signal has been recently investigated by several authors with interest particularly focused on the tropospheric layer, that is modelled starting from tbe main meteorological parameters observed on site. Phase shift due to the propagation of waves through the medium (troposphere and ionospbere) can be misinterpreted as deformation processes or topographical effects on the interferogramme from SAR image pairs. This paper deals with the influences of the dispersive ionospheric layer on SAR signal in Antarctica. The phenomenon is highly variable in time and space, due to the vicinity of the geomagnetic pole and is directly related to the Total Electron Content (TEC) values. Quantitative information on TEC values, at the time of the interferometrie images pair acquisition from the radar sensor, can be eventually obtained from locally acquired GPS measuremcnts or by ionospheric sounding. The magnitude of phase shift and the possible presence of "ionospheric" fringes can be then estimated.