5^ 



r— 























I.lna 





Suir-%r«y 



Tlma 



D«t:« 





\ 





188 



las 







1 



a 



3.010 

 11.09 



as ll&Y 93 

 aa MAY 9 3 









198 







3 



1139 



as MAY 9 3 











las 

 isa 







S 



IISO 



a 8 MAY 9 3 



































-5- 



V i 



V , /a.9 crnvi 



N.iy til) Pv^..^ 

 ^l"^ 2.5 cm- 

 2.7 cm (asi 

 11.1) 

 Envelope 

 (Standard Devietion, om) 



T ~ 



1.3 en 

 (0.9) 





3.1 om 

 (1.3) 



2 Ben 

 C1.0) 



r^'^^^ 



i 



1.6 om t 

 '°^' 3.8 on 

 (1.4) 



-in 



1 1 \ 1 



\ 





-+ 





1 





H 1 



Distance (m) 



Figure 9. 



Results of five repetitive surveys of profile line 188 using the CRAB/Geodimeter 

 system 



The distance accuracy is ± 10 mm in the tracking mode. The angle accuracy is ±3 sec in the 

 tracking mode and its vertical accuracy is ±3.0 cm at 1,000 m. Figure 9 shows the depth 

 change and the standard deviation of eight different offshore distances for five repetitive 

 profile surveys using the CRAB/Geodimeter survey system. The range of elevation changes 

 varies from 1.3 to 3.8 cm indicating that the system accuracy is somewhat better than the 

 Zeiss. 



One way to estimate the operational accuracy of the surveys is to measure the bottom 

 variation offshore where the bottom is relatively stable. A running mean filter was used to 

 filter out the real sea bottom change from the survey noise. Figure 10 shows the depth of 

 each survey and the five-consecutive-survey running mean at 800 m offshore. The standard 

 deviation of the residuals, which is the variance of the elevation to the five-survey running 

 mean, is 2.1 cm and 2.7 cm for the Zeiss surveys and the Geodimeter surveys, respectively. 



14 



Chapter 2 Profile Data 



