Visual codes are scanned to assist navigation. The visual code may be a Quick Response (QR) code that contains information useful to calibrating a variety of navigation-based sensors such as gyroscopes, e-compasses, and barometric pressure sensors. In an embodiment, an imaging device, an e-compass, an accelerometer, and a processor are elements of a system. The processor is coupled to the imaging device, the e-compass, and the accelerometer. The processor causes the imaging device to scan a visual code, read a yaw angle from the visual code, and computes an estimate of a yaw angle based on magnetic field measurements taken by the e-compass. The processor generates scale factors and biases determined from measurements generated by the e-compass. Based on scanning the visual code, the processor computes a quality factor based on the yaw angle read from the visual code and the estimate of the yaw angle.