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A study on the message structure of a satellite navigation system that minimizes TTFF(Time To First Fix)
Year 2020
Month
Journal November 2020 / 2020 IPNT conference
Author
In a satellite navigation system, it is important to calculate the precise position and to determine the initial position faster. In this paper, we propose a new message structure for a satellite navigation system that help to calculate the initial position more quickly than conventional message structures. The conventional message structure currently used by GPS takes an average of 27.6 seconds for Time To First Fix (TTFF) when operating as a standalone in a good reception environment as an open area. This is because the information required for location determination is transmitted every 30 seconds, of which essential information is concentrated in the early 18 seconds. To overcome these limitations, Assisted-GPS (A-GPS) technology was developed. The TTFF of A-GPS is drastically reduced by transmitting navigation messages received from reference GPS receivers that have already been initialized to receivers through communication networks such as cellular communication, and it takes an average of 9.7 seconds. In order to prove the improvement of the proposed message structure, we demonstrate that both the standalone and A-GPS have improved TTFF compared to the conventional GPS navigation message structure.