The invention discloses a combination precise single-point positioning method and
system based on inter-
constellation difference. The combination precise single-point positioning method comprise the steps that original observation values and auxiliary parameters, observed on an observation
station, of the different constellations are obtained; the original observation values are preprocessed; thepreprocessed original observation values are subjected to non-ionizing combination; inter-
constellation difference is conducted on non-ionizing layer combination observation of a single
constellation;an error observation equation is determined based on an observation model for inter-constellation difference; the preliminary position of the observation
station and observation
value noise are obtained; the elevating angles of all satellites are determined based on
satellite orbit parameters and the preliminary position of the observation
station; a
random model of each set of inter-
system difference observation values is determined on the basis of the elevating angles of all the satellites and the observation
value noise; a weight matrix is determined; and position parameters, inter-constellation difference
ambiguity parameters and
troposphere parameters are estimated through a least square method on the basis of the error observation equation and the weight matrix, and thus single-point positioning is achieved. According to the combination precise single-point positioning method, high-precision observation station positioning information and inter-
system time difference parameter information can be obtained.