However, arctic regions present a large assortment of terrain challenges. Large quantities of fresh surface snow can be present during certain times of the year. This fresh snow is soft, creating a potential sinking hazard for wheeled vehicles. Over time the winds harden the snow surface making it more amenable to locomotion. However, these same winds also sculpt the snow into dune-like structures that can be as large as one meter, again impeding motion. Tracked vehicles have been developed to overcome the specific challenges of arctic travel. The most famous of these devices is the snowmobile, but other variations exist ranging in size from small single person vehicles to bus-sized multi-passenger coaches. These platforms have been successful in military, commercial, and science applications since their development in the 1940s.
For navigation, a GPS unit connects to the embedded processor via the bluetooth interface, while a magnetic compass provides heading information via the I2C serial bus. Sensor data and internal state information are exchanged between scientists and other rovers over the bidirectional wifi link. Additionally, a 0.3 Megapixel wireless camera on-board each SnoMote provides real-time images.
A dual tread drive train system was implemented in response to these problems. The new system improved performance over the original design in two major ways. First, it nearly doubled the surface area in contact with the snow. By increasing the contact area, issues of sinking and traction loss in soft snow are reduced. Secondly, by modifying the rear sector of the chassis, the surface contact footprint was converted from a nearly triangular pattern to a more rectangular shape. This greatly improves the stability characteristics of the platform, reducing the likelihood of roll-over.
The original platform also suffered from steering deficiencies. The stock steering linkages of the snowmobile lacked the necessary rigidity to effectively maneuver through the depths of snow present as the test site. At the same time, the stock suspension system was too stiff, directly translating surface changes into body roll, instead of compensating ride height. To correct these issues, the stock single-arm plastic linkage was replaced with an aluminum double-wishbone design. The new parallel linkage system extended the ski separation by 30%. The newly installed suspension additionally included a spring-over-oil damper system, which was easily adjustable in the field. This allowed the stiffness to be tuned to the quality of the terrain.