BrickVista Tech-Notes

Power and Control Electronics
The "brain" of a rover, like Sojourner and the Mars Exploration Rover is a computer no more powerful than your high-end consumer laptop. Comprised of two electronics boards, (inside the WEB) they are generally referred to as the "CPU" Board and the "Power" Board, they each contain components which are responsible for power generation, conditioning, distribution and control, analog and digital I/O control and processing, computing, and data storage.

Navigation Sensors
Sensors, usually small cameras are used for navigation. While Sojourner only had three cameras the newer MER’s have nine
Mounted on the lower portion of the front and rear of the rover, these black-and-white cameras use visible light to capture three-dimensional (3-D) imagery. This is used by the rovers navigation software enabling it to "think on its own." And avoid any unexpected obstacles.

The cameras (used in pairs) wide field of view of about 120 degrees and are mounted directly to the rover’s body. Each map out a "wedge" of terrain up to 3 meters (10 feet) in front of it. The other type of camera sensor on a rover is used to create colour stereoscopic images. On the MER these are mounted on a mast assembly which lifts the cameras to to a height of 1.4 meters off the ground, giving scientists on Earth a human-like perspective of the surface of Mars.


Pancams take high-resolution images through the blue to infra red light spectrum.		Hazcam and Navcams are used for navigation. They see in black and white and have a broad field of view

Rover Control Work Station
Control of the rover is archived through the use of a powerful computer workstation. Actual terrain imagery is downloaded from the rover and stitched together to give a virtual 3-D map surrounding the rover. The operator uses this simulated environment to generate a sequence of commands for the rover to execute. Giant "lawn" darts are used as icons to show the intended path of the rover . These locations are uploaded to the rover for it to perform autonomously.

Such an interface provides an easy to use graphical user interface (GUI) to the numerous rover commands available.

THE CPU

A rovers on board computer (CPU) is no more powerful than a high end, powerful laptop computer. However it does contains special memory (RAM) which is tolerant of extreme radiation, and safeguards against power-off cycles. Memory is persistent which enables the Rover to shut down at night without loosing or erasing data.

MER: Memory (RAM)
Mars Exploration Rovers are equipped with 128 MB of DRAM and 3 MB of EEPROM. That's roughly 1000 times more memory than Sojourner

CCD CAMERAS

The cameras used for Rover navigation are small CCD (Charged Couple Device) Cameras similar to Web Cams.

With out cameras the Rover is blind. Rovers typically have more than one camera which they can use to navigate with.

SOJOURNER: 3 Cameras
2 forward B&W (Navcam)
1 rear 3 Colour (RGB)

MER: 9 Cameras
2 Forward B&W (Hazcam)
2 Rear B&W (Hazcam)
2 Mast B&W (Navcam)
2 Mast Colour (blue to IR)
1 Arm mounted B&W

HAZCAM AND NAVCAM
Hazcam and Navcams are both used for navigation. They take black-and-white stereoscopic images with a broad field of view, supplying mission scientists with the information they need to choose a safe path for the rover to traverse among potentially hazardous rocks.

PANCAM
Pancams take high-resolution views of the surface and sky. They capture images within the Blue to Infra Red light spectrum by using eight different colored filters. Data from the two cameras can be combined to make stereo panoramic images.

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