Mk V

The Mk V is the network-enabled version of the ROVLe family. It synchronizes the system timebases over an Ethernet network. The Mk V receiver triggers the Mk V transmitter when a ping is required, also over the network. Future versions of the Mk V may provide the ability to track multiple ROVs simultaneously.

The benefits of network synchronization are:

• It is more reliable than full-duplex (Mk III) synchronization because there is only one acoustic leg required, and the transponder does not need to hear the transceiver over the acoustic and electrical noise generated by the ROV.

• It is more convenient and accurate than simplex GPS-clock-based (Mk II) synchronization because neither end needs to be exposed to GPS signals, and there is no clock drift error.

The Mk V transmitter requires power from the ROV. Additionally, unless used in a Mk III duplex sync system, the user must provide access for the transmitter to the ROV network, and at the topside, access to the ROV network for the transceiver. Typically, this means an Ethernet switch with an open port is required in the ROV (example), and a network hub is required at the topside (example, example). The basic connectivity requirements for a network-enabled or network-synched system are shown here.

The Mk V system can update at a variable rate of 1 to 5 Hz. The rate is set automatically depending on range to the ROV and the acoustic attenuation of the signal path. A higher rate can provide a better input to the ROV's Extended Kalman Filter. High rate can be disabled in the configuration web page to save power.

When a Mk V transmitter is properly connected, it will click when the transducer is gently tapped with a fingernail or pencil, until it detects a Mk V receiver on the network. At that point it should switch to clicking at a rate of 1 to 5 Hz, depending on acoustic connection to the receiver.

A Mk V receiver communicates with the rest of the system via a power-over-Ethernet (PoE) connection. This cable can be up to 50 meters long depending on how well it carries the required DC power. Since the Mk V receiver needs to communicate with the transmitter via Ethernet, it is not possible to use the Mk V receiver with a serial or USB connection.