Research On Digital Level Measurement Of Airplane Based On Indoor GPS

As the last inspection process in the final assembly of airplane,the level measurement plays an important role,all of domestic and foreign aircraft manufacturers have regulations of airplane level measurement. Higher degree of accuracy is required by the new generation of airplane, thus,advanced measurement technology should be applied urgently in airplane level measurement.The traditional airplane level measurement has disadvantages such as low precision, to solve the low precision, high labor intensity and vulnerability to human factors,the airplane level measurement based on IndoorGPS system has been studied to implement digital measurement. The main contents and achievements are followed:1) The characteristics of all kinds of digital large-scale measuring equipment is analyzed,the rationality that the indoor GPS system is determined as measuring tool is certified according to the characteristics of airplane level measurement.The algorithm for orientation parameters in indoor-GPS is proposed,the measuring scheme is made based on the technical requirements of airplane level measurement.2) Coordinate systems in the measuring process are defined,12-parameters algorithm is proposed according to the theory of coordinate system transformation,the collocation method is adopted in the solution of transformed coordinates and the precision is improved. According to the non-uniplanar intersection of Indoor GPS ,the algorithm model for single point positioning is established, which is coincident with the actual facts.3) The error sources of the Indoor GPS system are analyzed,the measurement uncertainty of the system is analyzed by using weighting method,the relationship between the measurement uncertainty and the number of transmitters is obtained,and the conclusion is verified and analyzed by experiment.4) The software of airplane level measurment is developed,its functions including data processing,result analysis, query, ctiterion maintenance,report printing and so on,the operation to data becomes efficient and reliable showed by the application results.