Abstract: In order to process the rover and the reference stations GPS data with different sampling rates,a reasonable strategy is presented.When the observations of the rover are nonsynchronous with those of the reference station,the position of the rover will be estimated with the calculated precise "pseudo-ranges".Otherwise,the double difference(DD) model will be employed.The proposed method not only makes full use of the available data,but also saves the cost of data collection and transmission.An experiment was carried out,in which a rover receiver was mounted on an airplane while a reference station receiver was located on the ground.The rover positioning precision obtained by our presented method with nonsynchronous data was within several centimeters compared with those obtained by the DD model with synchronized observations.