Small-satellite Formation Autonomous Navigation Technology Based On The Configuration Information

Small-satellite formation, which has more advantages than single large satellites, has been becoming the focus of aerospace research. As autonomous navigation is critical for small-satellite formation, it is studied in the dissertation.All autonomous navigation schemes proposed in the dissertation base on the formation configuration information(inter-satellite range and relative angle information). The information can be applied in the relative orbit determination and absolute orbit correction of small satellites.To begin with, relative orbit determination technique which is similar to navigation constellation is proposed in the dissertation. The relative position of two follower satellites to a leader satellite is determined with range and angle information. And then, a reference constellation is set up with the leader satellite and follower satellites. With the reference constellation, the relative orbit of other follower satellites can be determined by inter-satellite range. The influence of the range among follower satellites and the plane of the reference constellation on the precision of relative orbit determination is checked by simulations.Second, the relative orbit determination based on range and relative angle measurement(with attitude deviation) of inter-satellite is studied in this paper. The measurement model with attitude deviation is established, and then attitude deviation and relative orbit is fitted via Kalman filter simultaneously. Simulations have been done to verify that the precision of relative orbit determination is related to the precision of measurement system and attitude deviation.Because of the miniaturization of small satellites, the precision of GPS receivers on these satellites is low and the position determination of these satellites is low-precision. In order to improve the precision, the relative orbit correction with pure range measurement of inter-satellite is proposed in the dissertation. The effectiveness of the method is tested by simulations using extended Kalman filter and unscented Kalman filter. The relative orbit correction without initial relative velocity measurement equation is also studied in the dissertation.Because relative orbit can be determined by making a difference of absolute orbit, the precision of it is related with the precision of absolute orbit determination. In order to improve the precision of absolute orbit determination, absolute orbit correction with range and relative angle measurement information of inter-satellite is proposed and four different kinds of correction combinations(once range measurement, twice range measurements, once range with once relative angle measurement and twice range with once relative angle measurement) have been studied in the dissertation. Simulations imply that the performance of orbit correction can be improved with more measurement.