Evaluation of the Quality of Altimetric Networks Using an Alternative Weighting Strategy

Abstract

Pre-analysis is a fundamental step in the planning of geodetic networks, as it establishes criteria for precision, reliability, and efficiency prior to data acquisition. This study evaluated two weighting methods, the inverse distance (ID) and the inverse of the product between the number of stations and distance (IND), in the reliability analysis of the adjustment of the Coastal Geodetic Reference Network (RGRC) and Tide Gauge Subnetworks (SRM), under different altimetric integration strategies. Four adjustment scenarios were considered, including individually processed networks, combined networks, and fully integrated solutions, all using minimal constraints to isolate external influences. The results showed that redundancy is a key factor for observation controllability. The SRMs exhibited satisfactory performance, with partial redundancies classified as “sufficient” to “good” (0.1 ≤  ≤ 1.0) in most cases, reflecting the technical rigor of the surveys. The RGRC, although presenting limitations in redundancy-sensitive indicators, with a predominance of “poor” classification (0.01 ≤  ≤ 0.1), showed adequate performance in standardized residuals (< 0.5 mm) and minimum detectable bias values (16.67 mm and 15.07 mm for ID and IND, respectively). The global chi-square test confirmed the internal reliability of the network at significance levels of 1%, 5%, and 10%. However, the IND weighting revealed inconsistencies in the stochastic model in scenarios with lower observation density. It is concluded that the RGRC demonstrates sufficient robustness and accuracy for high-precision geodetic applications, and that the quality of the SRMs supports their suitability for vertical variation monitoring associated with tide gauges