Systems and methods for travel distance measurement

A method for determining positioning of a scanner moving along a section of a pipe, comprising:

• an encoder and a counter measuring distance traveled by the scanner along a plurality of scan lines along a length of the section of the pipe;
• measuring acceleration and angular velocity of the scanner around a portion of the circumference of the pipe between successive scan lines;
• computing an angle of rotation of the scanner around the portion of the circumference of the pipe between successive scan lines, and
• and determining a distance traveled around the portion of the circumference of the pipe between first and second scan lines using the computed angle of rotation.

A positioning device for a scanner, comprising:

• means for detecting movement the scanner along scan lines parallel to a first axis of an object being scanned;
• means for counting encoder pulses from the encoder and configured to compute distance traveled by the scanner along a first scan line;
• means for measuring acceleration and angular velocity of the scanner;
• and
• means for computing an angle of rotation of the scanner along a second axis of the object being scanned that is perpendicular to the first axis using the received acceleration and angular velocity, and for determining a distance traveled along the second axis between first and second scan lines using the computed angle of rotation.