Mobile robot and method of operating thereof

1. A method of operating a mobile robot, the method comprising:

driving the robot according to a drive direction;

receiving robot position and movement data comprising:

gyro data of the robot including a robot angular rate and a robot acceleration;

drive odometry of the robot; and

global positioning coordinates of the robot obtained from satellite communications;

when the robot is at rest, determining a gyro bias based on the gyro data;

determining a three-dimensional gravity vector of the robot based on the gyro data;

determining an ego-motion estimate of the robot by:

subtracting the gyro bias from the gyro data;

resolving the gyro data relative to the three-dimensional gravity vector; and

adding angular rates from the resolved gyro data to the drive odometry of the robot;

when the satellite communications used to obtain the global positioning coordinates of the robot are available, determining a robot global position by combining the ego-motion estimate and the global positioning coordinates of the robot;

when the satellite communications used to obtain the global positioning coordinates of the robot are unavailable:

determining the robot global position of the robot based on at least one of the gyro data, the drive odometry, or dead reckoning; and

upon regaining the satellite communications, obtaining global positioning coordinates of a current location of the robot and determining the robot global position by combining the ego-motion estimate and the global positioning coordinates of the current location of the robot;

determining a driven path of the robot from an origin based on the robot global position;

displaying a drive view on a remote operator control unit in communication with the robot, the drive view having the driven path of the robot from the origin; and

displaying a map in the drive view using the global positioning coordinates, the driven path of the robot displayed on the map.

2. The method of claim 1 , further comprising at least periodically obtaining the global positioning coordinates of the current location of the robot to determine the driven path.

3. The method of claim 1 , further comprising using a Kalman filter to determine the three-dimensional gravity vector of the robot.

4. The method of claim 1 , further comprising using a particle filter to determine the robot global position.

5. The method of claim 1 , further comprising at least periodically receiving the robot global position in the remote operator control unit and connecting sequentially received robot global positions with a displayed line.

6. The method of claim 1 , further comprising determining the driven path of the robot before obtaining the global positioning coordinates and displaying the driven path in the drive view.

7. The method of claim 1 , further comprising determining a retro-traverse drive command after experiencing a loss of communications with the operator control unit to maneuver the robot along a path back to a communication location where the robot had established communications with the operator control unit and driving the robot according to the determined retro-traverse drive command.

8. The method of claim 7 , wherein the path back to the communication location coincides at least in part with a portion of the driven path.

9. The method of claim 1 , further comprising displaying a heading of the robot in the drive view.