Systems and methods for determining absolute velocity and position of a sensor device for measuring fluid and fluid conduit properties

A computer system for fluid conduit inspection, the computer system comprising:

• a memory, storing:
• sensor data collected by a sensor device during a measurement run from an interior of a fluid conduit while traveling along a length of the fluid conduit, the sensor data including:
• magnetic flux data comprising first magnetic flux data collected by a first magnetometer of the sensor device and second magnetic flux data collected by a second magnetometer of the sensor device, the first and second magnetometers each having a respective fixed position in the sensor device;
• and
• magnetometer separation distance data corresponding to a separation distance between the respective fixed positions of the first and second magnetometers;
• a processor in communication with the memory, the processor configured to:
• determine a plurality of time delay values over the measurement run, each time delay value determined by identifying a time delay between when a magnetic signal is present in the first magnetic flux data and when the magnetic signal is present in the second magnetic flux data;
• determine an absolute velocity of the sensor device for each of the plurality of time delay values using the magnetometer separation distance data and the respective time delay value to obtain a plurality of absolute velocity values for the sensor device over the measurement run, each of the plurality of absolute velocity values having associated time data indicating a time at which the sensor device had the respective absolute velocity value;
• and
• generate distance traveled data from the absolute velocity values and associated time data, the distance traveled data indicating a distance traveled by the sensor device during the measurement run at a particular time.