Journal of Civil Aviation University of China ›› 2025, Vol. 43 ›› Issue (1): 53-59.

• Aeronautical communications and navigation • Previous Articles     Next Articles

Integrity evaluation based on intelligent estimation of ionospheric delay

LU Dan, ZHANG Hongjian, ZHONG Lunlong, HU Tieqiao
  

  1. College of Electronic Information and Automation, CAUC, Tianjin 300300, China 
  • Received:2023-03-29 Revised:2023-06-01 Online:2025-04-09 Published:2025-04-09

Abstract:

Integrity is one of the performance requirements of civil aviation navigation systems, and ionospheric delay is an
important error source for integrity evaluation. For the single-frequency system, Klobuchar model is usually used
to correct the single-frequency signal, but the correction rate is only about 60%, and the accuracy is limited. This
paper proposes a method for estimating ionospheric delay and using it for integrity evaluation. Firstly, the ionospheric delay of observation station is trained by back propagation (BP) neural network, and the ionospheric delay
is calculated by BP neural network model of the observation station, which improves the ionospheric delay correction rate of the observation station. Secondly, the ionospheric delay of the aircraft equipped with single-frequency
receiver at its flight position is calculated by using the trained observation station BP neural network model and the
three-point interpolation method, and the integrity evaluation is carried out. Evaluation based on the data from
February to March 2015 shows that, when calculating the ionospheric delay, the BP neural network model and the
three-point interpolation method perform better than the Klobuchar model in some areas. They improve the correction rates of ionospheric delay during both daytime and nighttime, thus enhancing the accuracy of the protection level.

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