Design On Measurement System Of Lunar Orbit Rendezvous And Docking Radar

In order to meet the third-phase project of China’s manned lunar landing, lunarorbit rendezvous and docking technology is a key technology for spacecraft to and fromthe moon. The Earth’s orbit rendezvous and docking technology can’t immediately bemoved in the lunar orbit take into account the particularity of the lunar orbit and thevariability of the space environment in lunar orbit. To complete the mission, the newmeasuring system of the radar for rendezvous and docking must be designed to adapt tothe deep space environment measurement. This dissertation put forward a newmeasuring system for the lunar orbit rendezvous and docking, including mainly theradar signal modulation and the measurement of two spacecraft’s angle.The main work of this dissertation is to research two aspects at measurement ofrendezvous and docking through simulating at various factors, namely, the distancemeasurement and angle measurement. An innovative approach of signal modulation hasbeen put forward, that is Binary Offset Carrier(BOC) signal load carrier only, canimprove the ranging accuracy; at the same time, a new angle measuring method is usedunlike traditional interferometer measurement, it is solving ambiguity assisted thecarrier phase difference. The simulation and comparison analysis can verify itsfeasibility. This article can be divided into the following aspects:The first, the dissertation introduces the basic principle of radar range and anglemeasurement and put forward non-coherence spread spectrum measurement used on thedistance measurement. After analyzing the target, we put forward the research focus ofthis paper, introduce the principle of this focus, and finally decide to put to use thenon-coherence spread spectrum measurement. The main work of this part is to analyzetwo aspects affecting distance measurement, namely, the distance error caused bythermal noise and multipath. The advantage of non-coherent spread spectrum ranging inspacecraft payload designing is analyzed to prove the feasibility used in this way in thedesign.Second, the paper researches the BOC signal for ranging and designs BOC signal adding carrier only. The BOC signal for ranging performance is simulated, and itsadvantage can be derived by comparing with the conventional BPSK modulation; it canimprove the ranging accuracy better to load pure carrier in the BOC signal, on the otherhand, can also be used to study the dual-frequency solution ambiguity facilitating thefurther expansion of the design.Third, the angle measuring system using solving ambiguity assisted the carrierphase difference is designed. In order to reduce the payload’s of the spacecraft’s weightand complete the high-precision measurement, the reduction of the number of antennasof radar interferometer and the new measuring method are designed. In the new way, themeasurement is mathematical modeled, and then filtered by using Kalman filter toimprove the accuracy of measurement.In this paper, a new system adapted lunar orbit rendezvous and docking radar isdesigned through theoretical analysis and Matlab simulation. It is to meet thethird-phase project of lunar landing.