Instruments

The K10 rovers include a number of specialized instruments:

Ground Penetrating Radar

The K10 rovers are outfitted with a Ground Penetrating Radar (GPR). GPR is used to measure discontinuities in the dialectric constant of the soil at different depths down to a few meters. Different materials have different dialectric constants, so rock, dry soil, wet soil, and ice show up as layers in the GPR profiles. The GPR is used by the rover to produce a subsurface map of the environment. The GPR we are using was developed by NASA JPL for use on Mars rovers, and was part of the CRUX instrument package for lunar resource prospecting. On the moon, GPR could be used to detect water ice or to measure the depth of the regolith

3D Survey Lidar

One of the K10 rovers is equipped with a 3D surveying lidar. The scanning lidar provides dense coverage at millimeter accuracy over hundreds of meters distance. The lidar is used by the rover to produce an accurate topographic map of the environment. By registering terrain scans from many locations and combining with orbital information, the lidar helps to build a much higher resolution and more precise survey of the surface for planning infrastructure emplacement and surface operations. On the moon, lidar could be used to generate more accurate topographic maps that from orbit, as well as to see into permanently dark craters for navigation.

Stereo Cameras

K10 has a pair of stereo hazard-avoidance cameras. Images from these cameras are processed using stereo vision to estimate the shape of the terrain in front of the rover. The shape of the terrain is then analyzed to detect obstacles in the form of rocks too large to drive over or slopes too steep to climb safely. The terrain analysis is provided to the robot navigator which reasons about how to drive where the rover needs to go.

2D Laser Scanner

K10 has a Hokuyo 2D laser scanner which sweeps out a plane in front of the rover and measures distances. If the laser scanner detects large deviations from the expected ground in front of the rover, it acts as a “virtual bumper.” This provides enough look-ahead that the rover can avoid obstacles that are missed by the stereo vision system.

Digital Compass

K10 has a Honeywell HMR-3000 digital compass. The digital compass is a three-axis magnetometer combined with a roll and pitch sensor. The sensor measures the magnetic field and recovers the orientation relative to magnetic North. In test sites at lower latitudes, like in the Marscape at NASA Ames, there is a relatively constant offset between magnetic and true North, called declination. But Haughton Crater is very close to the magnetic North Pole, so the magnetic field is nearly perpendicular to the surface and the declination varies.

Sun Tracker

The sun tracker on K10 consists of a firewire camera, fisheye lens, and a dark neutral density filter. The camera has a view of the entire sky. If the sun is visible, the sun tracker can measure the direction to the sun very accurately. By combining a measurement of the direction to the sun from the sun tracker with a measurement of the direction toward “down” from an inclinometer, the sun tracker can estimate the orientation of the rover. The sun tracker provides an orientation estimate that is independent from the compass. This is important for places that have no magnetic field (like the Moon) or an unreliable magnetic field (like Haughton Crater).

Carrier-phase dGPS

K10 uses a differential GPS for position updates. The dGPS accuracy ranges from a few meters to a few centimeters depending on the availability of satellites and correction signals. The Extended Kalman Filter (EKF) onboard the rover incorporates information from the dGPS and continues to estimate the position of the rover if the GPS becomes unavailable.

Wheel Encoders

Wheel encoders on K10 record the rotation of drive motors, which, when multiplied by the gear ratio, tell how far the wheels have turned. The wheel encoders provide information on how far the rover is driving and turning, and the speed of the vehicle.

Steering Encoders

Steering encoders on K10 measure the steering angles at the four wheels. K10 can independently steer all four wheels. Information about steering angles is used to provide feedback on which way the rover is heading and how much it is turning.