Port of London Authority Tidal Monitoring System - POLATIDE 5: Detailed Case Study
Valeport and OceanWise have designed and delivered a complete tidal monitoring system, including tide gauges, telemetry equipment, servers, databases, system control, data management and display software, to the Port of London Authority. The system was installed in October 2013 and rigorous testing completed in February 2014.
The Port of London Authority (POLA) required a new tidal monitoring, telemetry and display system to replace an existing system that had been operational since 1990. After a pre-qualification exercise, a detailed specification and tender documents were prepared and a number of short-listed organisations asked to bid for the work.
This case study describes the system – colloquially known as 'POLATIDE 5' – and illustrates how OceanWise and Valeport have collaborated with POLA to create a system that is robust, reliable and meets POLA's original requirements with plenty of added-value components thrown in.
The system is now available as an EMC certified, off the shelf system that can be deployed easily and efficiently at any port or other similar maritime organisation in most locations worldwide.
The POLATIDE 5 system includes eight monitoring stations, four base stations and a data feed from fourteen existing upriver tide gauges operated by England's Environment Agency, and the Port of London themselves. OceanWise acted as system designer and integrator and provided all of the system control, data management and web based user display and administration software.
Valeport assisted with the system design and provided the monitoring equipment, battery changers and waterproof enclosures. These enclosures are now included in Valeport's standard product line.
Valeport TideMasters are used as the central point of each tidal monitoring outstation. The Druck pressure transducer and/or the VRS-20 Water Level Radar are used as sensors. Although not required for the Port of London, additional sensors can easily be added, for example a standalone anemometer or complete weather station or a conductivity and temperature probe. Output from the TideMaster provides data input to the dual telemetry system, which comprises a UHF radio modem and a serial to Ethernet/GSM transceiver.
The dual system provides a backup data telemetry route and allows the TideMaster to be interrogated and controlled remotely. If required, one of the telemetry routes can be omitted depending on requirements.
Power to the monitoring outstations is provided by a heavy duty battery that could be optionally charged from AC power, a solar panel and/or wind turbine. The power budget was designed to meet POLA's requirement to collect data for up to 7 days using the installed battery. All equipment, battery and charging units are housed in monobloc wall-mounted enclosures made from polyester and reinforced with fibreglass.
The enclosures provide IP 66 protection to IEC 60529 standards and resistance to external mechanical impacts. A locking device outside the sealed area guarantees the tightness of IP 66 over time. A door switch is included and cabled to the modems to trigger an alarm each time the door is opened or closed. Each enclosure design was EMC tested to an industrial standard and all sensors, antennae and other external cables connected through the enclosure, so that water tightness is maintained, while allowing the units to be readily disconnected.
Data transmission over the UHF telemetry route is via UHF modems installed at four base stations around the Thames Estuary. The base stations are co-housed with the POLA radar stations and connected to the POLA local area network (LAN). The POLA LAN is used to send data to the POLATIDE 5 data servers installed at POLA offices at Gravesend and Thames Barrier, Woolwich. A secondary telemetry system is incorporated with transmission via GSM/GPRS on a Mobile to Mobile Virtual Private Network (M2M VPN) set up for the purpose.
The M2M VPN provides data security but also ensures the modems retain the same IP address and hence can be contacted by the POLATIDE servers and any other authorised device. Data is sent from the M2M VPN to the POLATIDE data servers via the POLA Internet gateway and firewall.
In addition to the TideMaster, other instruments can be cabled to the modems and in doing so, the outstation is extended to measure other data types, such as waves and currents from an Acoustic Doppler Profiler (ADP), or act as base station for an offshore wave buoy, for example.
As well as one or two modems, the TideMaster can also be connected to an AIS transmission unit to broadcast tide and meteorological data to shipping with suitable AIS receivers installed via the IMO Message 8 (TideMet) encoding.
The data loading, management and display components were installed on each of the POLTIDE data servers. OceanWise's commercial off the shelf software products, Ocean Database and Port-Log, were used for this purpose.
Ocean Database (ODB) is a complete data management solution that loads and stores many standard types of simple and complex marine and environmental monitoring data. Associated parameters used in quality control and metadata creation are included, facilitating onward data exchange and use.
ODB is accessed through a variety of general and specialist software applications including GIS, Microsoft Excel and MATLAB, as well as the Port-Log web pages.
Full administration of users, stations, including automatically adding new stations and sensors, quality assurance parameters, tidal predictions and surge, and full synchronisation of all data and other parameters between the two databases is included.
Each component has been substantially improved during the course of the POLA contract in response to feedback from VTS and Navigation System Users and has been incorporated into the software as standard.
The Port-Log software provides various views on the system and scientific data depending on the level of user: User, Editor and Administrator, although these can be amended and new users added by the Administrator, if required. A map interface is included which shows the status of the overall system, and each outstation, sensor and telemetry units individually, as well as providing an access point to actual data.
The map interface is able to handle different base maps and additional data overlays, either stored locally within ODB or consumed from an external web server, which includes OceanWise's unique ENC Web Map Service (image right).
Alerts and triggers are generated according to editable parameters and thresholds e.g. battery levels, door locks, data transmission rates, water levels and QA failures.
Overall, Port-Log provides total control, administration and comprehensive visualisation of system performance and scientific data, as well as access to more advanced functionality and connectivity to external systems and web sites.
Examples of Port-Log mobile web page as seen on smartphone displays: