Indoor positioning and navigation systems and methods

A method for inspecting or maintaining a storage tank, comprising:

• positioning a vehicle at a first location inside the storage tank by a propulsion unit of the vehicle, the vehicle comprising at least one acoustic receiver (RX), at least one acoustic transmitter (TX), at least one inertial measurement unit (IMU);
• emitting, by the at least one TX of the vehicle, a first acoustic signal toward an acoustic hydrophone attached to the storage tank in a first location;
• determining a distance from the at least one TX of the vehicle to the acoustic hydrophone attached to the storage tank;
• emitting, by the at least one TX of the vehicle, a second acoustic signal toward a bright acoustic reflector attached to the storage tank in a second location;
• receiving, by the at least one RX of the vehicle, a second reflected acoustic signal from the bright acoustic reflector;
• determining a first azimuth angle of the vehicle with respect to a longitudinal axis of the vehicle and a first distance from the bright acoustic reflector;
• moving the vehicle in a direction of an azimuth direction to a second location of the vehicle inside the storage tank;
• and
• determining a second azimuth angle of the vehicle at the second location with respect to a second distance from the acoustic hydrophone and a second distance from the bright acoustic reflector.

A method for inspecting or maintaining a storage tank, comprising:

• traversing a vehicle inside the storage tank;
• determining properties of a storage tank by at least one sensor of the vehicle;
• navigating the vehicle by a navigation system comprising:
• an acoustic transmitter (TX) carried by the vehicle,
• an inertial measurement unit (IMU) sensor configured to at least partially determine a location of the vehicle with respect to the storage tank, and
• a propulsion unit configured to move the vehicle within the storage tank;
• and
• sending acoustic signal by the TX carried by the vehicle to an acoustic receiver (RX) fixed with respect to the storage tank,
• wherein the vehicle moves inside the storage tank in concentric arcs with respect to the RX fixed with respect to the storage tank, wherein the RX is a center point of the concentric arcs.

A system for inspecting or maintaining a storage tank, comprising:

• a vehicle comprising:
• a propulsion unit configured to move the vehicle within the storage tank;
• at least one sensor for determining properties of the storage tank;
• at least one inertial measurement unit (IMU) sensor configured to at least partially determine a location of the vehicle with respect to the storage tank;
• at least one acoustic transmitter (TX) carried by the vehicle;
• and
• at least acoustic receiver (RX) carried by the vehicle;
• an acoustic hydrophone attached to the storage tank in a first location;
• and
• a bright acoustic reflector attached to the storage tank in a second location,
• wherein the system comprises a non-transitory computer-readable medium having computer-executable instructions stored thereon that, in response to execution by one or more processors of a computing device, cause the computing device to perform actions comprising:
• positioning the vehicle at a first location inside the storage tank by the propulsion unit of the vehicle, the vehicle comprising at least one inertial measurement unit (IMU);
• emitting by the at least one TX of the vehicle, a first acoustic signal toward an acoustic hydrophone attached to the storage tank in a first location;
• determining a distance from the at least one TX of the vehicle to the acoustic hydrophone attached to the storage tank;
• emitting, by the at least one TX of the vehicle, a second acoustic signal toward a bright acoustic reflector attached to the storage tank in a second location;
• receiving, by the at least one RX of the vehicle, a second reflected acoustic signal from the bright acoustic reflector;
• determining a first azimuth angle of the vehicle with respect to a longitudinal axis of the vehicle and a first distance from the bright acoustic reflector;
• moving the vehicle in a direction of an azimuth direction to a second location of the vehicle inside the storage tank;
• and
• determining a second azimuth angle of the vehicle at the second location with respect to a second distance from the acoustic hydrophone and a second distance from the bright acoustic reflector.