A materials handling vehicle comprising a camera , a mast assembly , a mast assembly control unit, a fork carriage assembly , a vehicle position processor, and a drive mechanism configured to move the materials handling vehicle along an inventory transit surface of a warehouse , wherein: the mast assembly and the mast assembly control unit are configured to move the fork carriage assembly along a vertical lift axis; the camera is secured to the fork carriage assembly ; the materials handling vehicle characterized in that the camera is configured to capture (i) a forks down image of at least a portion of a rack leg positioned in a racking system aisle of a multilevel warehouse racking system , and (ii) a forks-up image of at least a portion of a rack leg positioned in a racking system aisle of the multilevel warehouse racking system ; and the vehicle position processor is configured to generate a forks-down coordinate X1 of the camera along a horizontal axis from the forks-down image of the rack leg , generate a forks-up coordinate X2 of the camera along a horizontal axis from a forks-up image of the rack leg captured with the fork carriage assembly at a lift height H1, determine a mast sway offset as a difference between the forks-down coordinate X1 and the forks-up coordinate X2, and determine a horizontally advanced position of the materials handling vehicle with the fork carriage assembly at the lift height H1 using the mast sway offset and a subsequently captured forks-up image of at least a portion of a rack leg positioned in the racking system aisle . the mast assembly and the mast assembly control unit are configured to move the fork carriage assembly along a vertical lift axis; the camera is secured to the fork carriage assembly ; the materials handling vehicle characterized in that the camera is configured to capture (i) a forks down image of at least a portion of a rack leg positioned in a racking system aisle of a multilevel warehouse racking system , and (ii) a forks-up image of at least a portion of a rack leg positioned in a racking system aisle of the multilevel warehouse racking system ; and (i) a forks down image of at least a portion of a rack leg positioned in a racking system aisle of a multilevel warehouse racking system , and (ii) a forks-up image of at least a portion of a rack leg positioned in a racking system aisle of the multilevel warehouse racking system ; and the vehicle position processor is configured to generate a forks-down coordinate X1 of the camera along a horizontal axis from the forks-down image of the rack leg , generate a forks-up coordinate X2 of the camera along a horizontal axis from a forks-up image of the rack leg captured with the fork carriage assembly at a lift height H1, determine a mast sway offset as a difference between the forks-down coordinate X1 and the forks-up coordinate X2, and determine a horizontally advanced position of the materials handling vehicle with the fork carriage assembly at the lift height H1 using the mast sway offset and a subsequently captured forks-up image of at least a portion of a rack leg positioned in the racking system aisle . generate a forks-down coordinate X1 of the camera along a horizontal axis from the forks-down image of the rack leg , generate a forks-up coordinate X2 of the camera along a horizontal axis from a forks-up image of the rack leg captured with the fork carriage assembly at a lift height H1, determine a mast sway offset as a difference between the forks-down coordinate X1 and the forks-up coordinate X2, and determine a horizontally advanced position of the materials handling vehicle with the fork carriage assembly at the lift height H1 using the mast sway offset and a subsequently captured forks-up image of at least a portion of a rack leg positioned in the racking system aisle . <EOS>