![]() In their analysis, the researchers were able to show that parked cars significantly reduce the quality of the elevation data: Parked vehicles scatter the satellite signal and cause it to be reflected several times before it reaches the antenna, like a cracked mirror. "And they are often surrounded by large parking lots - as is the case with the antenna we investigated in Boston." "But many GNSS receivers are mounted on buildings in cities or in industrial zones," explains Prof. This method works well if the surrounding ground is flat, like the surface of a mirror. To calculate the risk of flooding in low-elevation coastal areas, it is important to know this change - and thus the subsidence of the Earth surface - precisely. The can be used to calculate the distance between the antenna and the ground surface which can change over time. When superimposed on the directly received signal, it forms certain patterns called interference. ![]() This reflected part therefore travels a longer path to the antenna. Part of the signal is reflected by the nearby environment and objects and reaches the GNSS antenna with some delays. The measuring method is based on the fact that the antenna does not only pick up the direct satellite signal. Researchers, for instance, can measure the wave-like propagation of an earthquake and the rise or fall of a coastal area. Makan Karegar from the Institute of Geodesy and Geoinformation at the University of Bonn. "This has recently allowed our research group to measure elevation changes in the uppermost of soil layers, without installing additional equipment," explains Dr. For some years now, it has also been possible to measure the distance between the antenna and the ground surface using a new method. They do this using the US GPS satellites and their Russian counterparts, GLONASS. GNSS receivers can determine their positions to an accuracy of a few mm. The study, which was carried out by geodesists from the University of Bonn, investigated the location of a precise GNSS antenna in Boston (Massachusetts) as an example. At least that is what the study now published in the Geophysical Research Letters shows. Geodesy, a branch of the Earth Science to study Earth's gravity field and its shape, on the other hand, has benefited from the drastic reduction in human activity. Many of those affected by the lockdown suffered negative economic and social consequences. The journal Geophysical Research Letters now reports on this.Ī number of countries went into politically decreed late hibernation at the onset of the Covid-19 pandemic. More precise geodetic data are important for assessing flood risks and for improving earthquake early warning systems. The results show which factors should be considered in the future when installing GPS antennas. ![]() A study by the University of Bonn now shows that the quality of these measurements may have improved significantly during the pandemic, at least at some stations. view moreĮmerging use of Global Navigation Satellite System (GNSS) makes it possible to continuously measure shallow changes in elevation of Earth surface. It aims to deepen the joint anti-terrorism operations between the two militaries and demonstrate the firm determination and strength of the two countries to jointly safeguard international and regional security and stability.Image: The parking lot at a supermarket in Boston where the measurements were taken. The joint exercise kicked off on Monday at a combined-arms tactical training base of the People's Liberation Army in northwest China's Ningxia Hui Autonomous Region, and is set to continue until Aug. The two-day drill is designed to guide military command organs from both sides to optimize their command activities, which are related to intelligence, decision-making, planning, and control and assessment.įor the first time, a sub-command for Russian officers has been established within the joint command, and a command information system specially designed for the two militaries has been applied. 10 (Xinhua) - The first-phase drill of the ZAPAD/INTERACTION-2021, a joint military exercise between China and Russia, began in northwest China on Tuesday.
0 Comments
Leave a Reply. |