The invention relates to a method for determining an initial
orbit of a
satellite with an embedded physical knowledge neural network, which is used for determining an initial
orbit of a short arc segment under an
optical observation condition and providing support for subsequent precise
orbit determination. The network comprises an
encoder-decoder structure, an
encoder predicts the motion state of a
satellite in an orbit according to observation information, the decoder converts the predicted
satellite motion state into an observation value, the prediction accuracy of the
encoder is evaluated,
physical information of
satellite orbit dynamics is introduced into a
loss function, and the prediction accuracy of the
satellite orbit is improved. And
satellite orbit determination based on the neural network is realized. The input of the encoder is the observation angle quantity (namely
azimuth angle and
pitch angle) of the satellite relative to an observer, the
observation time and the position information (namely
longitude,
latitude and altitude) of the observer; the output of the encoder, namely the input of the decoder, is the absolute motion state quantity (namely the position and the speed of the satellite in a geocentric
inertial coordinate system) of the satellite in the orbit and the position information of an observer, and the output of the decoder is the observed quantity of the satellite relative to the observer. When the network is trained, firstly, a decoder is trained by taking a
mean square error between a predicted observation value and a real observation value as a
loss function, and a transformation relation from a
satellite motion state to the observation value is learned; fixing the structure and parameters of a decoder, training the whole encoder-decoder network, calculating the derivative of the predicted satellite absolute state quantity relative to the
observation time, and calculating the
physical information loss of a speed item and an acceleration item; adding the
physical information item loss and the
mean square error of the observed quantity, constructing a total
loss function, and optimizing network parameters through error back propagation; in the reasoning stage, an encoder network is used for reasoning, and the absolute motion state quantity, predicted by an encoder, of the satellite is converted into an orbit element form, namely, the initial orbit is determined.