Hi, first time posting here. I'm working on satellite orbit determination and wish to add in perturbing accelearations in addition to the earth's graviatational field. I will be adding in acceleration due to the moon, sun, atmospheric drag, etc... The acceleration due to the earth's graviational field at the specefic satellite altitude is about 7 m/s and the acceleration from the sun, for example is on the order of 10^-7 m/s. I have an initial state vector, I would like to incorporate these accelerations and produce a state vector at a later time. I am working in matlab and having difficulties mainly with units and integration. A short example of matlab code would be handy. Right now I am getting an ever increasing velocity and this is happening because I am doing the integration as if it were a linera problem. How to integrate so that it is orbital. Thanks!