Sensor fusion of spectroscopic data and gyroscope accelerations for a direction indication in handheld radiation detection instruments

A method is shown to estimate the position of a (single) radiation source fusing the data from a sodium iodide detector and a gyroscope while panning the detector. Based on geometry considerations, the search motion of a detector is modelled as angular panning and waving motions. Correlation of the sensor data stream from the an gyroscopical accelerometer with the count rate event data of the detector is shown to be a suitable predictor for the direction of incoming radiation. The method also allows for a rough distance classification, where a distant source or a homogenous radiation field can be distinguished from a single source near to the detector. Aim of the research is not to establish a precise angular determination, but instead a reliable, robust indication whether a user should search to the left or right hand side of the instrument.