A Design for a Trusted Community Bathymetry System. Issue 4 (3rd July 2020)

• Record Type: Journal Article
• Authors: Calder, Brian R.; Dijkstra, Semme J.; Hoy, Shannon; Himschoot, Kenneth; Schofield, Andrew
• Is Part Of: Marine geodesy. Volume 43:Issue 4(2020)
• Page Start: 327
• Page End: 358
• Publication Date: 2020-07-03
• Subjects: Bathymetry -- Crowdsourced Bathymetry -- GNSS volunteered geographical information ellipsoid-referenced survey -- Trusted Community Bathymetry; Marine geodesy -- Periodicals; Hydrographic surveying -- Periodicals; 526.99
• DOI: 10.1080/01490419.2020.1718255
• Languages: English
• ISSNs: 0149-0419

Abstract

Abstract: Marine Volunteered Geographic Information (informally "crowdsourced bathymetry") has raised much interest within the authoritative hydrographic community as a means to cheaply gather information to satisfy chart updating requirements. So far, however, a routine path to the official chart has been rare, mainly due to lack of calibration and other metadata that would satisfy liability concerns. As an alternative to these ideas, a data collection system is proposed which, by design, can auto-calibrate and provide other data quality guarantees, and thereby generate data that by construction should be qualified for hydrographic use. This idea is termed here Trusted Community Bathymetry (TCB). A design for such a system is outlined, and its performance demonstrated experimentally through a prototype system based on a low-cost, post-processed GNSS receiver and NMEA data logger. By comparison against NGS control and survey-grade GNSS equipment, it is shown that the TCB system achieves centimeter to decimeter-level positioning in 3D, auto-calibrates vertical offsets to the sonar transducer within a decimeter, and provides realtime uncertainty estimates for ellipsoid-referenced soundings. Additionally, in an underway field trial, the total vertical uncertainty of the soundings is shown to be within the limits required for IHO Order 1b (S.44, 5 Ed.) surveys.