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On the possible use of satellite fixed positions for Argo float profiles in case of wrong fixes by GPS

Satish, RUVN and Udayabhaskar, TVS and Suresh Kumar, N and Ravichandran, M and Dinesh, K and Kumar, A (2015) On the possible use of satellite fixed positions for Argo float profiles in case of wrong fixes by GPS. International Journal of Earth Sciences and Engineering, 8 (2). pp. 710-715.

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Indian National Centre for Ocean Information Services (INCOIS) had deployed Iridium based Provor Bio-Argo floats obtained from NKE Instrumentation, France. These floats are fitted with GPS for obtaining accurate position of the Argo profiles. However there are cases where in the GPS fitted with the Argo floats tend to give wrong coordinates of profile position owing to unknown reasons. In the present work we discussed the possibilities of using the Iridium satellite fixed position as a substitute of GPSfixed locations in place of wrong GPS positions. For this, statistical analysis was done by comparing the GPS and Iridium satellite fixed profiles positions of 258 profiles from 5 floats which had no problem with the GPS. For each comparison, the GPS fixed position with least Circular Error Probability (CEP) radius was chosen. It was observed that CEP radii are relatively consistent with distances between GPS and Iridiumsatellite fixes with a correlation of 0.85. The study suggests that on an average the Iridium satellite based positions tend to differ from the GPS fixed positions by 0.09°. On the whole CEP radii are found to be consistent with the difference between Iridium satellites and GPS fixed positions. Based on this we suggest a quality flag of 2 (implying probably well) for positions with CEP radius less than or equal to 4 Km and flag 4 (implying bad) for all other positions.

Item Type: Article
Additional Information: Copyright of this article belongs to CAFET INNOVA Technical Society
Uncontrolled Keywords: Argo floats; CEP radius; GPS; Satellite
Subjects: Oceanography > oceanography
Depositing User: INCOIS Library
Date Deposited: 17 Aug 2015 10:52
Last Modified: 17 Aug 2015 10:52

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