Unmanned Systems Technology 024 | Wingcopter 178 l 5G focus l UUVs insight l CES report l Stromkind KAT l Intelligent Energy fuel cell l Earthsense TerraSentia l Connectors focus l Advanced Engineering report

10 Platform one February/March 2019 | Unmanned Systems Technology The idea of an unmanned vehicle being able to operate on land, in the air and both on water and under it is very attractive (writes Peter Donaldson). To that end, Western Michigan University student Gabriel Prescinotti has produced a degree thesis on an electric Land Air Sea Rover (LASR) that could operate in all those environments and transition between them. The goals of the LASR effort were to achieve 30 s of operation in each mode, demonstrate transition from any mode to any other – including taking off from under the water – and to add the ability to crawl along the bottom of a body of water. Most of these were achieved during testing. Using an earlier Land Air Surface Submarine (LASS) as a starting point, which could operate in all those environments but couldn’t transition between them, its tricycle gear was replaced with a set of tracks for propulsion in all domains except air. In addition, larger diameter propellers were fitted, along with four small vertical thrusters for depth control of the buoyant vehicle and maintaining contact with the bottom, and a camera for streaming video. Using 3D-printed polymer wheels, the tracks contributed to the 1612 g LASR’s 222 g weight reduction over the LASS. On land it demonstrated the ability to start and travel on rough surfaces and on an incline. In the air it proved its stability and ability to hover, translate, respond quickly and accurately to control inputs, achieving a height of about 6 m. On the water it floated and moved without leaving the surface. As a submarine though it only managed to submerge to about 15 cm instead of the intended 30 cm owing to a comms limitation, so in rover mode it was tested down to about 15 cm to avoid that problem. Future work will look at a static dive system in place of the thrusters, a lower frequency comms system, improvements in video streaming that would allow a first-person viewing option, and modified gearing to improve its efficiency on land. Research Go-anywhere rover test Inertial Sense has developed a GPS positioning module with RTK error correction with 2-3 cm accuracy (writes Nick Flaherty). The μIMU is a miniature calibrated sensor module consisting of an inertial measurement unit (IMU), magnetometer, barometer and onboard L1 GPS (GNSS) receiver. Data output includes angular rate, linear acceleration, magnetic field, barometric altitude and GPS. It measures 25.4 x 25.4 x 11.2 mm. “The incredibly small size of our new micro INS with RTK sensor, in combination with its extremely affordable price point, will make this type of highly sophisticated technology accessible for general consumer applications for the very first time,” said Walt Johnson at Inertial Sense. “We are offering RTK at a size, accuracy and price point that the market has never seen before.” By optimising the manufacturing processes for high-volume applications, the cost of the module is a tenth of that of other RTK modules. Inertial Sense has bundled evaluation kits that can be used in both rover and base station configurations, and included 900 MHz radios with onboard logging capabilities to provide the error correction data to the module. Ultra-small INS with RTK Navigation Inertial Sense’s micro INS with RTK The LASR has achieved most of its design goals