Design And Implementation Of Ground-specific DME Calibration Device

DME(Distance Measurement Equipment)is an important equipment in modern navigation systems and a Ranging-standard for the distance-orientation(?-?)system of the ICAO(International Civil Aviation Organization).It provides the aircraft with continuous and accurate straight-line distance information to the designated location and can be used to guide the aircraft together with other equipment.The ground station of DME requires performance verification to be used for distance navigation of the aircraft.At present,a common international method is to use a pilot machine for flight verification or to use a simulated interrogator for testing.The method of testing with simulated interrogator is simpler and more suitable for normal commissioning,inspection and on-site maintenance.However,the accuracy of the self-produced simulator in China is the same as that of the DME equipment.It is impossible to accurately calibrate the DME ground station,and the foreign simulator has functional limitations.Therefore,it is necessary to design a DME ground station measurement test equipment and study the calibration method of the test equipment.These can complete the test and establish a traceability chain of DME ground station indicators to achieve reliable traceability of testing data.At first,this paper introduces the development history of navigation equipment,the working principle of DME equipment,and the detection method of DME ground station at home and abroad.Then introduced the work to be done in this article.Next,the function and composition of the ground ranging calibration device to be designed in this paper are introduced.The article describes the composition and working principle of the distance measuring device,the position reference measuring device,the calibration method of the distance measuring device,and the calibration specifications of the calibration instrument.Then introduces the design method of the ranging detection equipment,describes the performance indicators and circuit principles of the internal modules,and introduces how to reduce the quantization error in the circuit and how to correct the inconsistency of the time delay.Next,the article analyzes the reasons for the selection of the comprehensive calibration software development environment and explains the use of the integrated calibration software.Finally,the composition of the measurement uncertainty is analyzed in detail,and the A and B types of uncertainty of each component are calculated to obtain the evaluation of the measurement uncertainty of the calibration device.At the end of the paper,the future development direction of the device is also proposed.This design uses virtual instrumentation,software radio technology,and uses the same technical system and signal format as the airborne equipment of DME,and has developed a set of DME ground station detection equipment with more than three times higher accuracy than the DME.The calibration method of the test equipment is also studied,and the measurement uncertainty is analyzed and calculated,so that the measurement results can be traced back to the professional metering station,ensuring that the testing data is true,accurate and reliable.