Guidelines for the coordinated enhancement of the maritime position, navigation and time data system

Reliable knowledge of a ship’s position and movement in relation to other traffic participants and obstacles is a fundamental requirement for navigation and avoiding collisions and groundings. Consequently, the onboard provision of resilient position, navigation and time data (PNT) is emphasized by the International Maritime Organization’s (IMO) e-navigation strategy, solution S3 “Improved reliability, resilience and integrity of bridge equipment and navigation information” and by the assigned risk control option RCO5 “Improved reliability and resilience of onboard PNT systems”. An initial step towards resilient PNT has been realized by the maritime community with the development of the performance standards for shipborne multi-system radionavigation receiver equipment (MRR). This MRR performance standard (PS) supports the full use of data coming from current and future radionavigation systems and services. Consequently, the combined use of several global navigation satellite systems (GNSS) and the additional use of space based augmentation systems (SBAS) as well as optional terrestrial radionavigation systems (e.g. eLoran or R-Mode) will be supported to increase the performance of positioning and timing. As a second step, the development of guidelines for an onboard PNT (data processing) unit has been identified as supplementary and necessary. The starting point is the onboard use of a combination of GNSS receivers and autarkic systems (e.g. radar, gyro, echosounders with bathymetric data) for a comprehensive provision of required PNT data. Redundancy in the available data enables the application of integrity monitoring functions to evaluate the current usability of safety-critical data and components. The aim of the guidelines is the specification of data processing rules towards the resilient provision of standardized PNT data and integrity information. For this purpose, a modular architecture for an onboard PNT system is introduced and scaled to the need for data input as well as the performance of data output.