Uncrewed Systems Technology 044 l Xer Technolgies X12 and X8 l Lidar sensors l Stan UGV l USVs insight l AUVSI Xponential 2022 l Cobra Aero A99H l Accession Class USV l Connectors I Oceanology International 2022

109 Oceanology International 2022 | Report about the kinds of waves and heaving a boat is dealing with, and hence if your ocean survey asset should be recalled and recovered to prevent damage.” Trimble CenterPoint RTX delivers real- time corrections without the end-user needing to set up base stations (as is often the case with RTK processing) and at the time of writing, the satellite-based correction service was available to USVs up to 200 km offshore across most of the world’s continents. Morton added that it can still work beyond these distances, and some customers are trialling the extent to which it continues working. “As well as being useful for persistently surveying oil rigs, wildlife habitats and other critical offshore assets, we’re seeing more and more small USVs going into very dangerous areas on behalf of wider ranges of clients,” he said. “So it’s important for all operators to know exactly where their USV is at all times and to track the kinds of environmental conditions it’s dealing with.” Also at the show was iXblue, which exhibited a range of solutions across hydrographic survey, autonomy, navigation and underwater positioning. One of these was its new FlipiX sensor tow vehicle, which expands the survey capabilities of the company’s DriX USV (see UST 25, April/May 2019). Explaining something of the FlipiX’s development history, Guillaume Eudeline said, “Customers needed the ability to make heavily detailed multi-sensor surveys, the kind that take multiple outings and sensor reconfigurations across multiple missions, but they wanted to do it all in a single USV deployment. “The DriX is capable of using a great many sensors from the surface, but on top of that our customers wanted the sensors to go deeper below the surface in order to get more detailed and accurate hydrographic data. So we had no choice but to develop a new remotely operated tow vehicle [ROTV], which is the FlipiX.” In typical operations, a FlipiX is towed behind the DriX at speeds of 3 to 7 knots, so that the latter can use its sensors for depths down to 50 m. The FlipiX can ‘swim’ down to 50 m while running sidescan sonars (the EdgeTech 4205 being the most popular choice at present) as well as a single magnetometer. “We are also developing a frame that will attach to the FlipiX and hold several magnetometers simultaneously for wider magnetic field survey capabilities,” Eudeline added. The ROTV autonomously holds its altitude to ±10 cm and also maintains pitch and roll to within 1 º of error. Altitude-holding is achieved using data from an onboard altimeter and buoyancy adjustments from an auto-depressor. The FlipiX is designed to be positively buoyant normally; the auto-depressor is essentially a bottle that contracts in response to external pressure. Pitch and roll are held owing to the FlipiX being constructed similarly to a fixed-wing aircraft, with wing flaps that adjust for its ‘flight’ manoeuvres through the water. Meanwhile, the umbilical running from the ROTV to the USV transmits data from the FlipiX to the DriX in real time, and the latter’s data link delivers all the data to the end-user, for them to view in their GCS via iXblue’s HMI software. The cable also sends power from the DriX to the FlipiX. “Of course, end-users also need precise geo-referencing of the FlipiX’s sonar and magnetic data,” Eudeline noted. “For that, we’ve installed our Gaps USBL system on the DriX to gauge in real time the position of a beacon on the FlipiX relative to the USV, and combine that data with the DriX’s GNSS updates to stamp the FlipiX’s survey data accordingly. “Overall, this makes the FlipiX a part of the DriX autonomous solution, with the USV running the ROTV in a mode of ‘supervised autonomy’ in order to capture a huge body of data from the surface to the subsea environment.” Airmar told us about three new products it said are of critical importance to autonomous marine vehicle manufacturers and operators. The first is its 200WX-IPX7 WeatherStation multi-sensor, named for its IPX7 rating, indicating that it can endure the harshest weather and sea conditions; this is rare among such solutions. The system measures barometric pressure from 300-1100 hPa, wind speeds from 0 to 40 m/s, wind direction accurate to ±3 º (at 10 m/s wind speeds) and other parameters. “It is also uniquely suited to mobile applications, as it integrates GPS position with a three-axis accelerometer, rate gyro and magnetometers to compute Uncrewed Systems Technology | June/July 2022 The FlipiX sensor tow vehicle from ixBlue