A selection has been made from the wide variety of Global Navigation Satellite Systems (GNSS) receivers currently available on the market. Although there are many other GNSS receivers, the GNSS models featured in this survey are predominantly designed for usage within the hydrographic industry. In comparison to land surveying GNSS receivers, the maritime receivers have several specific characteristics which make them more suitable for usage in maritime environments.

In most of the featured GNSS models the antenna and receiver are physically separated. The two units are connected to each other with a coax-cable. This separation is useful in hydrographic environments because the physical location of the receiver on survey launches is often separated further from the antenna.

Another important capability of 'maritime' GNSS receivers is the capability to transmit a Pulse per second (PPS) signal to other survey sensors. A PPS signal is an electrical signal that very precisely indicates the start of a second. The PPS signal allows the user to precisely time synchronise the different survey sensors on board of a survey launch. This functionality is, for example, frequently used during multi-beam surveys to time synchronise the different sensors.

As a result, the receivers also contain multiple additional ports such as serial ports, UTP ports, USB ports, etc. in order to be able to output the GNSS signals to the different survey sensors on board of survey launches.

As in other years, a trend can be identified in that the latest GNSS models have more channels. This is a logical follow-through as these receivers would in the future also like to support the Galileo frequencies (L1, E5a and E5b). Furthermore, the new GNSS receivers also contain more processing capacity than previously and thus a higher update rate can be achieved.

Traditionally, most units came with separate software to enable the user to modify the settings in the GNSS receivers. The user, however, can now access most models via a web-interface to control and adjust the settings in the GNSS receiver.

The Author
Gerrit van der Vliet of Navigation Solutions Europe distributes surveying and navigation technology, specialising in GNSS Sensors, OEM GNSS, land survey, wireless hardware and software, for markets requiring high accuracy and reliability. With 20 years GPS/GNSS experience, we understand the varied needs of our customers and can provide custom solutions to match your needs.
www.navigationsolutions.eu