Evaluation of GPS Post-Processed Kinematic (PPK) techniques. Application to hydrological monitoring in the Amazon basin
Abstract
The water stage variations in the hydrological basins are traditionally monitored by network of in-situ gauges. Generally, these gauges are not levelled. Therefore, the stages from one gauge cannot be compared in an absolute way to stages from another gauge to derive for example the slope of the water surface although, the slope information is a key parameter for the hydro-dynamic modeling of the flow in the basins. In the Amazon basin, the GNSS reference network is sparse and the usual differential positioning technique can not be used to level the gauges with high accuracy. In this presentation we discuss the strategy to leveling the gauge using an alternate technique, the GPS Post-Processed Kinematic PPK technique. We used the latest version of the GINS CNES/GRGS software which includes a sequential filtering as an option to the traditional least squares approach. In addition a test to solve for un-differential GPS phase observation ambiguities using GRG IGS analysis center products as been conducted. The data sets used in this work were collected from GPS receivers installed on-board boats during field campaigns along-strike the major contributors of the Amazon basin, namely the Solimoes, Negro and Madeira rivers. The gauge level is obtain when the boat overpass a gauge, by simple subtraction of the absolute level of the water surface given by the GPS systems and the stage read on the gauge. The efficiency of this method is evaluated by comparing to the results derived from fix points. Such a leveled hydrological network can contribute to assess the quality of heights series from satellite altimetry over the rivers. We present results of such evaluation for the Jason-2, ENVISAT and ICESAT missions.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.G11B0914M
- Keywords:
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- 1240 GEODESY AND GRAVITY / Satellite geodesy: results;
- 1241 GEODESY AND GRAVITY / Satellite geodesy: technical issues;
- 1899 HYDROLOGY / General or miscellaneous