The AXYS HydroLevel™ buoy accurately monitors water level elevation in any body of water where a surface following buoy can be deployed. HydroLevel™ is a precision instrument, which incorporates the latest GPS RTK and motion sensing technologies, making the HydroLevel™ the leading solution for an accurate, easy to use, rugged economical product for the measurement of water elevation.

The buoy’s stainless steel hull has a high strength to weight ratio and provides secure mooring and lifting points. Two hull options are available: the HydroLevel Mini 0.6m hull, and the regular HydroLevel 0.9m hull.

The HydroLevel™ buoy uses the NCT-2050G StarFire GPS receiver to provide real time accurate three dimensional position by the Global Differential Global Positioning System (GDGPS). When used during hydrographic surveys, the buoy will enable the depth & contours of the seabed to be corrected for the true water surface elevation changes, as measured on the absolute three dimensional WGS 84 earth centered, earth fixed (ECEF) reference frame using GPS real time kinematic (RTK) or post- processed (PPK) techniques. GDGPS measurements provide solid earth tide corrections and the HydroLevel™ buoy GPS receiver incorporates these real-time correctors at the position and time measured by the GPS receiver.

In addition to position measurement, a motion sensor on the buoy measures the pitch, roll and heading of the buoy in real-time. Along with the position of the GPS antennae, the pitch, roll and heading are used to calculate the true position GPS antenna, and therefore of the water level in which the buoy is floating. The earth tide corrections, pitch, roll and heading data are all supplied to the buoy processor, which performs the necessary tilt corrections, averaging and filtering.

The HydroLevel™ GPS Processor was developed from the successful low-power WatchMan500 processor, specifically designed by AXYS for the marine environment. The processor integrates sensor systems and provides onboard data processing, data logging, telemetry and diagnostic/set up routines.

The HydroLevel™ buoy can be used as a self contained data logging system or can be configured with a variety of telemetry mechanisms.  The buoy is also capable of monitoring its moored location through the use of the onboard GPS receiver and a buoy mooring WatchCircle™ algorithm. If the buoy drifts from its defined location, the WatchCircle™ Alarm is activated at the shore base station.

Data transmitted from the buoy via Iridium, VHF or cellular telemetry includes buoy configuration, status data, position and WatchCircle™ Alarm messages. Data is also stored on the buoy’s internal data logger. AXYS Data Management System (DMS) Software, can be installed on a PC to automatically receive, decode and display data transmitted from the buoy. Decoded data is auto-archived in both file and database formats for further use.

Set up and communication with the HydroLevel™ buoy takes place through a waterproof connector on the buoy hull or alternatively, via a Bluetooth or 802.11 WiFi wireless connection built into the buoy. All of the buoy set-up parameters can be adjusted and monitored using the wireless interface, enabling easy field configuration and testing.

Due to its high rugged design and solid state electronics, HydroLevel™ can withstand the rigors of deployment and recovery operations, including impact, shock, spinning and temporary submergence.

Product Documentation

HydroLevel Buoy (PDF, 195 KB)

Case Study - AXYS provides buoy-based water level monitoring solution for the Naval Oceanographic Office (NAVOCEANO)