ALIS
A proposal for the development of an At-sea Location Information Service

ALIS is based on mining geographical position data and accompanying GIS manipulation of dynamic and static spatial datasets to provide a unique marine location-enabled service. ALIS will tell a mariner who and what is in their vicinity, be it the nearest marina or a weather warning so they can react/plan accordingly. ALIS uses a range of current GNSS, satcom and terrestrial data communication services and complements other onboard navigation systems. It is not intended to be safety critical, but it does provide advisory information. It is aimed at all classes of boat user, but particularly the mass-market general boat user who may not have many onboard electronics, and is based around a simple thin client and server architecture which is straightforward to deploy. The ALIS system architecture is shown in the diagram. The various elements shown are: - ALIS client: This consists of a bespoke software application resident on a user’s onboard computing device (e.g. laptop, PDA, SmartPhone). The client software allows a user to define an ALIS query/request, transmit their location and to receive information from the ALIS server. The client software interfaces to: - the user’s onboard GNSS receiver, from which the ALIS client extracts their real-time position. - the user’s onboard mobile communications device(s), e.g. satcom terminal, satellite phone, etc., which provides a two-way internet connection from the client to the ALIS server. - the user’s locally stored nautical chart dataset for backdrop data display in the client software to give spatial context to ALIS data. - ALIS server: The shore-based ALIS server consists of a data ingestion component that receives data from a number of third-party sources, a RDBMS for storing this data and position information received from ALIS users, and a data access portal that provides an API to the database for client information requests and retrieval. The server interfaces to the following type of data sources: - local data. Where data for ingestion is not available over a network, it may need to be ingested, either manually or via a process, from a local source. An example of this is Almanac information supplied as data files on CD. - remote data. Much of the data ingested is available from remote databases or services. This includes data retrieved from third-party online databases or data received from third-party transmission systems (e.g. AIS or NAVTEX). - third-party clients and services: ALIS has a well documented API and uses XML to pass requests and results between a client and the server. Therefore third-party client software developers can access ALIS. An example of this could be vessel-tracking services that access ALIS to retrieve position information on any ALIS subscriber.