Research On Detection Of Sea Ice Using GNSS-R

The most important factor of disaster is sea ice.which directly affects marine transportation,port facilities and the safety of incoming ships.As the cold source of the global climate system,the Antarctic sea ice has the effect of magnifying and driving in the climate change system,which has a great influence on the global climate and environment,and is considered to be an important indicator of the global climate.In the case of Bohai as an,sea ice disaster has a great impact on China’s economy.In order to mitigate the impact of sea ice disaster,the domestic and foreign scholars began to study on sea ice detection.The traditional sea ice detection means can not detect the sea ice in real time under the influence of the weather condition,and the cost of the experiment is relatively large,so it is the key problem to develop the real time effective and economical and environmental detection means.The GNSS signal is not affected by the weather.It can receive satellite signals by the receiver at any time,and has a large number of data sources.In the process of experiment and data processing,only the receiver,receiving antenna,notebook computer and other experimental equipment are needed,and the economic consumption is low,and it can be detected without interruption for a long time.The different information brought by GNSS direct and reflected signals is applied to different occasions,respectively.Direct fire signal(GNSS-D)is the most common use of positioning,can provide accurate time information,location information and navigation information,can realize the function of real-time navigation.The reflection surface is received by the reflector(GNSS-R)after the receiver is received by the receiver.The reflection surface can be identified by the analysis of the reflected signal.Because of the above features,GNSS-R technology has become one of the most popular technologies in the field of marine research at home and abroad.It has been widely used in the fields of Yu Haibing detection,sea surface height measurement,sea surface wind field measurement,marine oil spill detection,polar ice cover detection and so on.In the process of using direct signal positioning,it is found that the reflection signal can reflect the characteristics of the reflector.Since then,scholars at home and abroad have begun to study the sea ice detection using GNSS-R technology.The Fabra team used the data of GPS satellite signal for the first time to propose the model of polarization ratio to retrieve the trend of sea ice change,and verified the possibility of GNSS-R detecting sea ice.Through two experiments in Bohai and Antarctica,the feasibility and specific technical route of using the signal of the Beidou satellite system in China to detect sea ice and the use of GPS signal detection in the Antarctic region are studied in this paper.In this paper,by combining the direct and reflective signals of GNSS,the sea ice conditions of the reflecting surface are identified by their ratio,and the change of sea ice concentration is detected.The Beidou satellite constellation is the autonomous satellite navigation system developed by our country.So far,the technology has been very mature and has a good coverage in the Asia Pacific region.In this paper,the experiment in Bohai has used the Beidou satellite signal to complete the detection of sea ice density and so on.The feasibility of its application to sea ice detection is verified and specific techniques are given.The operation route.The GPS satellite constellation has achieved global coverage.The satellite data on the zenith map of the Antarctic that correspond to the elevation range of the polarimetric model are all GPS satellites.Therefore,we use the GPS satellite signal in the Antarctic experiment,and use the carrier receiver to realize the large range movement observation of the sea area around the Antarctic continent,and give the specific technical route of the ship load detection method.The main contents and achievements of this paper are as follows:1.This paper introduces the key technologies of sea ice test,including the type and polarization of electromagnetic waves,the basic principle of sea ice,and the introduction of the Beidou satellite and GPS satellite used in this paper.The process of data acquisition and data processing is introduced,and the main errors in data processing are analyzed.2.This paper conducted the experiment on the shore of the Antarctic sea ice and Bohai ship experiment two experiment.The first shore based experiment used the Beidou GEO satellite,which uses a single satellite to detect the sea ice condition of the whole experiment using a single satellite using the GEO satellite to the geostationary nature.We used the reflected signal from Beidou GEO B1 frequency band for 6 days.The result verified the possibility of long-term detection of sea ice by the Beidou satellite shore based experiment.In the experiment,we used Beidou GEO’s C01,C02 and C03 satellites to detect for 6 days.The results of polarization ratio of 3 satellites are positively correlated with atmospheric temperature.The correlation ratios of C01,C02 and C03 to atmospheric temperature are 0.61,0.72 and 0.57,respectively.3.In the second experiment,we installed the GNSS-R receiver on the thirty-first Antarctic expedition ship,"Snow Dragon",and used the GPS receiver to receive the direct and reflected signals.The location of the ship borne receiver and GPS satellite varies with time.In the process of data processing,the QT program is developed to dynamically select three satellites that conform to the elevation and azimuth conditions.Each group uses the average of the polarization ratio of three satellites as the use of data to eliminate the error caused by the use of different satellites.Using the US ice and snow center data and the field survey photos as the contrast data,the experimental results show that the GPS satellite can detect the sea ice density by using the polarization ratio model.When the elevation angle of satellite is within a certain range,the intensity of sea ice can be reversed by using different GPS satellites,and the sea ice concentration and polarization ratio are negatively correlated.