Abstract

Traditionally, geoid models have been validated using GNSS-levelling benchmarks on land only. As such benchmarks cannot be established offshore, marine areas of geoid models must be evaluated in a different way. In this research, we present a marine GNSS/gravity campaign where existing geoid models were validated at sea areas by GNSS measurements in combination with sea surface models. Additionally, a new geoid model, calculated using the newly collected marine gravity data, was validated. The campaign was carried out with the marine geology research catamaran Geomari (operated by the Geological Survey of Finland), which sailed back and forth the eastern part of the Finnish territorial waters of the Gulf of Finland during the early summer of 2018. From the GNSS and sea surface data we were able to obtain geoid heights at sea areas with an accuracy of a few centimetres. When the GNSS derived geoid heights are compared with geoid heights from the geoid models differences between the respective models are seen in the most eastern and southern parts of the campaign area. The new gravity data changed the geoid model heights by up to 15 cm in areas of sparse/non-existing gravity data.

摘要

传统上，大地水准面模型仅在陆地上使用GNSS水平基准进行验证。由于无法在海上建立此类基准，因此必须以不同的方式评估大地水准面模型的海域。在这项研究中，我们提出了一个海洋GNSS /重力运动，其中现有的大地水准面模型通过GNSS测量结合海面模型在海域进行了验证。此外，还验证了使用新收集的海洋重力数据计算出的新大地水准面模型。该活动是由海洋地质研究双体船Geomari（由芬兰地质调查局运营）进行的，该双体船于2018初夏在芬兰湾芬兰领水的东部来回航行。从GNSS和海面数据，我们能够以几厘米的精度获得海域的大地水准面高度。当将GNSS得出的大地水准面高度与大地水准面模型中的大地水准面高度进行比较时，在战役区的最东部和最南端看到了各个模型之间的差异。新的重力数据在稀疏/不存在的重力数据区域将大地水准面模型的高度最多更改了15 cm。