I would like to have an estimate of radiation dose associated with a certain trajectory/ flight path in Earth's vicinity (e.g. transfer from LEO to GEO). For this I am looking for a mathematical model, which can/ should be an approximation which provides a radiation effect based on distance to Earth's center to estimate the effect for each point on a given trajectory. Where can I find something like this? It should be an as simple as possible function (as I said it is only meant to be an approximation).
Thank you and best regards!