Simultaneous determination of location of ocean-bottom criistal-deformatioil stations and 3D acoustic velocity profile improvements in marine geodesy

我们已经开发了一个测量海底地壳变形的观测系统。这是一个复合系统，使用动态全球定位系统技术定位船上换能器，并使用声学技术在船上和海底换能器之间进行测距。我们完成了重复测量，在三个网站，共有七个海底站在700-1004米的苏尔蒂加湾的深度。2002年，在第一个现场，我们对两个海底应答器进行了为期两个月的五次测量。我们获得了每个海底传感器的单次测定的水平和垂直位置的标准误差分别为4-9 cm和4- 13 cm，重复测定的水平和垂直分量的标准误差分别为16-20 cm和31-44 cm。在2002年和2003年的每一年，我们分别在第二个和第三个地点放置了两个海底换能器。单年内的单次和重复测量的误差与第一个站点的误差非常相似，但2002年和2003年之间的海底传感器位置差异是上述结果的3至10倍，这表明测量中涉及一些未知但简单的误差。我们相信，在2004年进行的下一次测量中可以解决这个问题。因此，本研究所开发的系统可以应用于海底地壳形变的观测，其误差在允许的范围内

We have developed a observation system to measure seafloor crustal deformation. It is a composite system using a kinematic GPS technique for positioning an onboard transducer and an acoustic technique for ranging between the onboard and seafloor transducers. We accomplished repeated measurements at three sites with a total of seven seafloor stations at depths 700-1004 m in the Surtiga Bay. At the first site, we measured to locate two seafloor transponders five times for two month in 2002. We obtained for the single determination of each seafloor transducer the standard errors of 4-9 cm and 4-13cm for horizontal and vertical locations, respectively, and for the repeated, determination the standard errors of 16-20 cm and 31-44 cm for the horizontal and vertical component, respectively. At each of the second and third sites we located two seafloor transducers two times in each year of 2002 and 2003. The errors in the single and repeated determinations within single years are quite similar to those of the first site, but the differences in location of seafloor transducers between 2002 and 2003 are 3 to 10 times larger than the above results, suggesting that some unknown but simple errors are involved in the measurements. We believe that this can be solved in next measurements carried out in 2004. It is thus concludes that the system developed in this study can be applied to observations of seafloor crustal deformation with a tolerable allowance level