The Research Of Passive Location Technology For The Landing At Sea Of The Manned Spacecraft

Recently, China’s manned space technology has reached an advanced level in theworld. The space mission of our country is the human lunar exploration in the future.When the manned spacecraft completes the task, the astronauts return the earth. Thewhole return process contains four stages. It brakes away from the rail, free-falling,re-entering the atmosphere and landing the earth. Similarly, when manned spacecraft onthe way to the moon, the stoppage of the spacecraft or the disease of astronauts resultsthe manned spacecraft return to the earth from the interrupt. For the above twosituations, you need to determine the landing site after return from an interrupt. We alsoneed to rescue the return capsule as fast as possible.This paper aims to study the following parts:(1) the selection of the landingground of the capsule return under the normal circumstance or the failure on the way tothe moon. How to select the landing site of the return capsule under the normal case orthe dangerous situation, and analyzes the advantage and disadvantage of the sea landing.Combine with the Apollo spacecraft landing at sea, we need to raise our sea landingprogram;(2) This paper also provides passive location tracking for the landing segmentof manned spacecraft. We need to use the passive time positioning technology toconfirm the position of the capsule. This paper also analyses the positioning accuracy.This includes the type the aircraft, the pitch of the aircraft, the position error of theaircraft, the time error and the height of the aircraft.(3) This paper designs a spreadspectrum signal. This paper mainly analyzes the anti-multipath capability of thissignal. In order to analyze which kind of signal is more suitable for the distress signal,This paper compares the anti-multipath ability of the LAS-BOC signal and BOC signal;(4) this paper analyses the synchronization technology of the receiver. This paperintroduces three methrods.they are the Satellite two-way relay method. Satellite viewdirect synchronization method. Satellite has apparent indirect synchronization method;(5) the most important part of this paper is the location and the tracking of the returncapsule. If the accuracy of the location is too low, it is hard to rescue the capsule. Thispaper mainly studies the dynamatic model of the capsule. Basing the CV model and the IMM model, we use the EKF algorithm and the UKF algorithm to track its trajectory. Atthe same time, we need to simulate its trajectory, and we compare the tracking error ofthe two filtering algorithm.From the sea landing program of the manned moon, as well as using the TDOA totrack the return capsule,we hope that this paper play a key role to the actual project ofour country. China’s manned space technology is much more mature, but the mannedmoon landing is later than the United States for a few decades, and the landing on thesea is never experience. In light of this, this paper focuses on the issue of this subject, inorder to make our country’s manned moon landing project can be done smoothly in thefuture.