1998 Winter Expedition

Expedition Profile

The 1998 expedition  will demonstrate the robot Nomad's search and classification of rocks and meteorites and its autonomous navigation of polar terrain. The primary demonstration will evaluate Nomad's classifier in distinguishing and characterizing rocks and meteorites using high-resolution imagery and optical reflection spectroscopy. The secondary demonstration will conduct field evaluation of newly developed autonomous capabilities, including navigation with stereo vision and laser sensors, patterned coverage planning, and "blind autonomy." Additionally, the field team will evaluate a landmark-based navigation system, a millimeter wave radar, Nomad's locomotion on ice and snow, and a communications architecture.

A field team from Carnegie Mellon University, NASA Ames Research Center, and the University of Pittsburgh will reestablish a base camp at approximately 80 deg 18' South - 81 deg 16' West, and will operate there for six weeks. Field operations will take place between November 1 and December 15, 1998. The Chilean Air Force and the Chilean Antarctic Institute will provide transportation and logistical support, and will participate with scientists and field experts. A research scholar from France's LAAS-CNRS (with funding from the French Polar Institute, IFRTP) will evaluate stereo vision and laser perception sensors in the context of a robotic program for Antarctic exploration. Please click here for more information.

Primary Demonstrations

Experiments

Robotic Rock/Meteorite Classification

The purpose of the December 1998 Antarctic field season is to test the autonomous meteorite classifier under true field conditions. Nomad will acquire data from new rocks and classify them with limited human input. This will establish conclusively whether the current system (sensors and classifier) is practical for field robotic deployment and will determine its suitability for robotic meteorite search.

Nomad will explore the areas of Independence Moraine, the region where data and rock samples were acquired last season. Nomad will collect images and spectral data from new samples, and feed the information to its classifier for assessment. Physical samples will be taken from each rock that Nomad examines for analysis by a field geologist on the team. Nomad?s classifier output will be compared to the geologist?s analysis for validation of Nomad?s capabilities.

Nomad will be in its meteorite search mode for this expedition, so it will either move autonomously or be directed to a waypoint by an operator. Through an interface, the operator will monitor the panoramic images and, if desired, direct the robot to an area of interest via teleoperation and/or commands to the maneuver planner. Once closer to the area of interest, the operator can then select a particular rock and enter it into the database. The operator can generate a high-resolution image of the object and by radio communicate with a sensor operator who will place the spectrometer on the rock of interest. The operator will issue a command to the appropriate sensor to take a sample. Following sample acquisition, Nomad can resume autonomous navigation or receive further directions from the operator. Real-time data processing and classification analysis will be performed on board Nomad.

A Bayes network-based rock/meteorite classifier will perform assessments from the visual imagery and reflectance spectra of rocks obtained in the field. The classifier is capable of identifying and discriminating between the various local rocks (mostly marble, limestone, granite, quartzite and some igneous rocks) as well as meteorites and subclasses thereof (achondrite, chondrite and iron).

Autonomous Classifier

The 1997 expedition demonstrated that, despite significant variations due to cloud cover and other atmospheric conditions, the best results are attained using spectral data from the visible to the infrared portions of the light spectrum (350 - 2500nm). Even if confined to only the visible wavelengths (400 - 900nm), approximately 90% of rock samples and 90% of meteorites are correctly classified as either rocks or meteorites. When identifying rock types, approximately 5% of rocks are misclassified using spectra data, with limestone and marble being the most likely to be confused. This is not surprising since both consist of the same minerals.

Because the Patriot and Independence Hills regions of Antarctica are believed to lack meteorites, an area will be seeded with meteorites in order to test the classifier utility.  A geologist viewing high-resolution images returned by Nomad will designate possible candidates for Nomad?s classification.  In addition, an expedition further inland from Patriot Hills (to the polar plateau) will allow human investigators to search for meteorites with a handheld version of Nomad?s spectrometer as well as a digital camera.  This expedition will be an opportunity to acquire more data from different geographical areas, particular those in which meteorites may be found.

Science Interface

This season, a human operator will control the prototype meteorite search system by way of an interface created to allow control and testing of nearly every component in the science system.  Although it can track the status of most science system components, this interface will deal most directly with three systems:

Autonomous Navigation of Polar Terrain

The autonomous navigation system will be vigorously tested and operated under various polar conditions, with testing of the system?s perceptual sensors as the primary focus. Additionally, Nomad?s ?blind autonomy,? which is its ability to detect and circumvent a close object, and new advances in Nomad?s patterned coverage search will be assessed.

Nomad?s performance will be evaluated on the four major terrain types present at Patriot Hills: blue ice field, snow, moraine, and sastruggi. The testing of the stereo vision and laser sensors on these terrain types will be particularly important, as Nomad has never traversed such terrain. The effects of and need for filters, particularly polarizing, on the stereo cameras will be a major part of testing.

Perceptual Sensors

For the Antarctic expedition, Nomad?s navigation system is configured with two types of perception sensors: stereo vision and laser sensors. Each sensor independently acquires the appropriate data and creates a map. The maps are grids in which each cell contains a goodness value and a certainty. A goodness value is a rating of how beneficial it is for Nomad to be in that particular position; a certainty is the sensor?s confidence level in the data. These maps are then passed to Morphin, a program which merges them and determines which direction will provide the maximal benefit.

The goodness value can be adapted to evaluate any number of measurements, including science value and solar availability. This attribute, plus the system?s ability to accommodate additional sensors, make this methodology suitable for use in another context, potentially space exploration.

Blind Autonomy

This new feature of the navigation system assists Nomad by evaluating the robot?s ability to detect when it is too close to an object.  While Nomad monitors motor currents and angle sensors to determine if it is traversing dangerous ground, blind autonomy allows both monitors to direct a backup and turn maneuver in order to recover and turn away from the object.  This ability will be very important in Antarctica where the functionality of stereo and laser on ice fields is not known.

Patterned Coverage Search

In addition to blind autonomy, autonomous navigation involving patterned coverage will be evaluated this year. In patterned coverage search, the operator will define a polygonal area to cover and the pattern to use. Nomad will then follow that pattern in order to maximize coverage.

While Nomad travels, the operator will be able to select an object of interest from Nomad?s panoramic view and enter it into the database. The operator also will be able to direct Nomad in taking various sensor readings; Nomad will execute these commands even if they require deviating from the initial planner because the maneuver or path planner can create a route to the region of interest. When the measurement is complete, Nomad will resume the initial pattern, returning to the point from which it left and continuing its autonomous traverse.

Location

Initial activities will be held at Patriot Hills, but in the course of the expedition, Nomad will traverse much of the area between the Patriot Hills and the Independence Hills. The following maps show the planned traversals and important distances.

Schedule

Date Activity Details
Oct 15 Equipment departs from Pittsburgh  
Oct 23 Expedition team departs from Pittsburgh  
Nov 1 Ice deployment of team and equipment FACH C-130 from Chile to Patriot Hills, weather permitting.
Nov 1-8 Operations at Patriot Hills Initial tests and activities close to the Chilean camp. Side flight to southern locations.
Nov 9-29 Operations between Patriot and Independence Hills Field demonstrations and technology experiments.
Nov 30 - Dec 6 Endurance traverse Final leg of expedition. Nomad returns to Camp via East End.
Dec 6-10 Packing and camp break, return to Chile End of research activities. Public display of Nomad in Punta Arenas, Chile.
Dec 15 Equipment departs, team breaks  

Communications

Data and voice transmission will be conducted using the INMARSAT satellite constellation. Powered by the Sun, an INMARSAT terminal will sit at a hilltop location on the Patriot Hills to transmit data and voice to the US. The hilltop box will also house a router, ARLAN, power inverter, power regulator, and a battery. The ARLAN allows wireless ethernet communications from the operations tent to the hilltop router. To turn on the communications link, the team will telnet to the router from a computer on the local network and issue a simple command that initiates a phone call from the INMARSAT terminal. About a minute later, all the computers in Antarctica can talk to all the computers on the SCS network at CMU. This satellite link will be used periodically every hour or as needed when there are new hi-res images of rocks, spectrometer data, classification results, and telemetry to send to the web server at CMU.

The map below describes the communications scenario during the 98 Antarctic expedition.

Robotic Technologies

One of the unique technologies being field tested on Nomad during this expedition is the science autonomy system (SAS). The aim of the SAS is to be able to spot interesting rock/meteorite targets in the robot's vicinity, move near them, deploy sensors, and classify the mineral composition of the target to determine whether it is a meteorite. Ultimately, the SAS should be capable of doing all of these things autonomously. This season a prototype version is being tested to field test the individual components of the SAS under human guidance. Therefore, a science interface was created that allowed the users to coordinate and evaluate the entire system. An SAS white paper is available here that describes each of its components.

Additionally, the expedition is using an operator interface designed at NASA Ames Research Center to drive Nomad and monitor weather and robot telemetry information. The original version of this operator interface is described here. The operator interface used this season is designed to run more reliably, and on a low-resolution laptop in intense sunlight.

Pre-Expedition Testing

Throughout 1998, the improved perception, planning, and autonomous navigation capabilities of Nomad were tested at a barren slag site in Pittsburgh. This allowed the team to evaluate aspects of Nomad's modified locomotion, autonomous safeguarding, patterned coverage planning, and servo-pointing of the high-resolution science camera. To assess the readiness and functionality of Nomad's major subsystems for polar weather conditions, the project team tested Nomad in a sub-zero storage facility, where the robot was subjected to temperatures as low as -25oC. After sitting in the chamber overnight, the robot successfully started up. Its heaters successfully increased operating temperatures to levels acceptable for the electronics systems. On-site test of the science sensor heating systems were also performed.

Additionally, the expedition team was exposed to the very low temperatures they would experience as well as the logistical problems posed by operating the science autonomy system interfaces while wearing polar gear.

Photo Gallery

These are images of Nomad taken during its cold chamber testing:
 
Nomad enters the cold chamber Evaluating Nomad's traction on an ice sheet
Nomad executes a point turn after a cold start Autonomous driving and testing of safeguarded navigation with laser and stereo cameras

Here are new images sent back from Antarctica on November 15th. The first are of Nomad in transit to Antarctica in Chile:
 
Nomad in Chile Nomad without the outer shell, showing its internal electronics box Nomad and the Chilean hanger

These are images taken near the CMU main camp:
 

These next images show Nomad's traversals on Antarctic terrain.
 

These images display the various sensors and systems that were field tested:
 
Nomad's sensor mast LAAS laser from Riegl Nomad's science camera
The Patriot Hills viewed by Nomad's science camera Another image from the science camera Ice mobility tests

Robotic Search for Antarctic Meteorites 1998
All material on this page is property of NASA and Carnegie Mellon University. Any image or text
taken from this site and incorporated into another document without consent violates the Copyright
Law of the United States and the Berne International Copyright Agreement.
Send comments, questions, or suggestions to Dimitrios Apostolopoulos.
This document prepared by Michael Wagner.