Comprehensive Evaluation of VHF Digital Link Mode 3 System
2008 Volume 2008 Issue 120 Pages 1-17
Details
2008 Volume 2008 Issue 120 Pages 1-17
VDL (VHF Digital Link) Mode 3 is a digital communication system for ATS (Air Traffic Services). Mode 3 architecture is based on TDMA (Time Division Multiple Access) technology and has various useful functions for ATS such as simultaneous communications of both digital voice and data, voice anti-blocking, urgent downlink request and so on.
We have developed a Mode 3 experimental system consist of four radio stations and a central station, which is compliant with ICAO (International Civil Aviation Organization) VDL Mode 3 SARPs (Standards and Recommended Practices) and technical manual. In this paper, we report comprehensive evaluation results for the system such as flight experiments, interoperability tests with the Mode 3 system of FAA (Federal Aviation Administration) and subjective evaluations for operation. Main results are summarized as follows;
•Data communication of Mode 3 can reach to the line of sight distance around. The limit of digital voice communication is a little farther than the line of sight since powerful error correction is implemented on voice coder.
•The voice quality and the functionalities of Mode 3 are better than traditional analog voice communication.
•Some defects which affect the datalink operation on ATN (Aeronautical Telecommunication Network) are found. We have reported the defects and countermeasures to ICAO.
