Advanced Navigation's GNSS Compass Used by Nortek for Its Next Surveying Solution

Nortek’s Signature VM vessel-mounted ADCP package opens up new opportunities to the survey community while offering operational convenience and reduced complexity. Data quality can be optimised, and both errors and initial installation time can be substantially reduced by using components that are integrated at a high level.

The challenge

A vessel-mounted ADCP measures and logs water velocity and direction below the vessel to create a profile of what is happening beneath the water's surface. To quantify and correct the measured data for accuracy of position, ADCP measurements typically require a precise secondary reference for velocity and heading that is highly reliable. Besides ADCP bottom tracking functions, referencing data can be provided using an external GNSS receiver and a non-magnetic heading source, such as a gyro compass.

Using external correction sources has traditionally been challenging to interface with ADCP data. Additionally, synchronisation between the systems must be completely dependable, as any delays in heading and velocity data can significantly deteriorate the integrity of ADCP data. Nortek sought to find a solution that provided accurate heading to assist ADCP for their latest platform with a view that it would cater for existing needs and remain viable into the future.

The solution

The GNSS Compass provides the necessary satellite-derived geographical information for position and velocity. It also delivers accurate non-magnetic heading via its integrated dual GNSS antennas. All components are built into a tough, marine-tolerant housing with a standard screw mount.

Data synchronisation issues of past serially connected equipment are virtually eliminated, with nanosecond accuracy via Ethernet PTP connectivity between the ADCP and GNSS Compass. Similarly, common Ethernet-based compatibility provides a much simpler set-up and reliable high-speed data transfer to previous technologies.

"GNSS Compass is an easy, time and cost-effective instrument" - Herman Huitema, VM Product Manager, Nortek.

The result

The GNSS Compass has proven to be an ideal companion instrument to the Signature VM ADCP.  The fact that it can replace a GNSS and gyro-compass with a standalone unit that has a single Ethernet connector and supports a proprietary protocol provides enormous benefits in reducing set-up time and not requiring specialised knowledge.

Nortek’s integration of the GNSS Compass to their Signature VM package provides a high-level vessel-mounted ADCP/navigation solution. It also offers a rapid and easy set-up experience that users expect from the latest technologies and integrations.