GRU–Transformer Hybrid Model for GNSS/INS Integration in Orchard Environments

Precision positioning in orchards relies on Global Navigation Satellite System and Inertial Navigation System (GNSS/INS) integration. However, dense foliage often causes GNSS blockages, degrading accuracy and robustness. This paper proposes an optimized GNSS/INS integrated navigation method based on...

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Main Authors: Peng Gao, Jinzhen Fang, Junlin He, Shuang Ma, Guanghua Wen, Zhen Li
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Agriculture
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Online Access:https://www.mdpi.com/2077-0472/15/11/1135
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author Peng Gao
Jinzhen Fang
Junlin He
Shuang Ma
Guanghua Wen
Zhen Li
author_facet Peng Gao
Jinzhen Fang
Junlin He
Shuang Ma
Guanghua Wen
Zhen Li
author_sort Peng Gao
collection DOAJ
description Precision positioning in orchards relies on Global Navigation Satellite System and Inertial Navigation System (GNSS/INS) integration. However, dense foliage often causes GNSS blockages, degrading accuracy and robustness. This paper proposes an optimized GNSS/INS integrated navigation method based on a hybrid Gated Recurrent Unit (GRU)–Transformer model (GRU-T). The GRU–Transformer hybrid dynamically adjusts the process noise covariance matrix within an error-state Extended Kalman Filter (ES-EKF) framework to address non-stationary noise and signal outages. Forest field tests demonstrate that GRU-T significantly improves positioning accuracy. Compared with the conventional ES-EKF, the proposed method achieves reductions in position root mean square error (PRMSE) of 48.74% (East), 41.94% (North), and 61.59% (Up), and reductions in velocity root mean square error (VRMSE) of 71.5% (East), 39.31% (North), and 56.48% (Up) in the East–North–Up (ENU) coordinate frame. The GRU-T model effectively captures both short- and long-term temporal dependencies and meets real-time, high-frequency sampling requirements. These results indicate that the GRU–Transformer hybrid model enhances the accuracy and robustness of GNSS/INS navigation in complex orchard environments, offering technical support for high-precision positioning in intelligent agricultural machinery systems.
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institution Kabale University
issn 2077-0472
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publishDate 2025-05-01
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spelling doaj-art-6b59a70d2e884d58a78811a42f18aa692025-08-20T03:46:47ZengMDPI AGAgriculture2077-04722025-05-011511113510.3390/agriculture15111135GRU–Transformer Hybrid Model for GNSS/INS Integration in Orchard EnvironmentsPeng Gao0Jinzhen Fang1Junlin He2Shuang Ma3Guanghua Wen4Zhen Li5College of Electronic Engineering (College of Artificial Intelligence), South China Agricultural University, Guangzhou 510642, ChinaCollege of Electronic Engineering (College of Artificial Intelligence), South China Agricultural University, Guangzhou 510642, ChinaCollege of Electronic Engineering (College of Artificial Intelligence), South China Agricultural University, Guangzhou 510642, ChinaCollege of Electronic Engineering (College of Artificial Intelligence), South China Agricultural University, Guangzhou 510642, ChinaCollege of Electronic Engineering (College of Artificial Intelligence), South China Agricultural University, Guangzhou 510642, ChinaCollege of Electronic Engineering (College of Artificial Intelligence), South China Agricultural University, Guangzhou 510642, ChinaPrecision positioning in orchards relies on Global Navigation Satellite System and Inertial Navigation System (GNSS/INS) integration. However, dense foliage often causes GNSS blockages, degrading accuracy and robustness. This paper proposes an optimized GNSS/INS integrated navigation method based on a hybrid Gated Recurrent Unit (GRU)–Transformer model (GRU-T). The GRU–Transformer hybrid dynamically adjusts the process noise covariance matrix within an error-state Extended Kalman Filter (ES-EKF) framework to address non-stationary noise and signal outages. Forest field tests demonstrate that GRU-T significantly improves positioning accuracy. Compared with the conventional ES-EKF, the proposed method achieves reductions in position root mean square error (PRMSE) of 48.74% (East), 41.94% (North), and 61.59% (Up), and reductions in velocity root mean square error (VRMSE) of 71.5% (East), 39.31% (North), and 56.48% (Up) in the East–North–Up (ENU) coordinate frame. The GRU-T model effectively captures both short- and long-term temporal dependencies and meets real-time, high-frequency sampling requirements. These results indicate that the GRU–Transformer hybrid model enhances the accuracy and robustness of GNSS/INS navigation in complex orchard environments, offering technical support for high-precision positioning in intelligent agricultural machinery systems.https://www.mdpi.com/2077-0472/15/11/1135transformerGRUsensor fusionKalman filtertrajectory predictionorchard navigation
spellingShingle Peng Gao
Jinzhen Fang
Junlin He
Shuang Ma
Guanghua Wen
Zhen Li
GRU–Transformer Hybrid Model for GNSS/INS Integration in Orchard Environments
Agriculture
transformer
GRU
sensor fusion
Kalman filter
trajectory prediction
orchard navigation
title GRU–Transformer Hybrid Model for GNSS/INS Integration in Orchard Environments
title_full GRU–Transformer Hybrid Model for GNSS/INS Integration in Orchard Environments
title_fullStr GRU–Transformer Hybrid Model for GNSS/INS Integration in Orchard Environments
title_full_unstemmed GRU–Transformer Hybrid Model for GNSS/INS Integration in Orchard Environments
title_short GRU–Transformer Hybrid Model for GNSS/INS Integration in Orchard Environments
title_sort gru transformer hybrid model for gnss ins integration in orchard environments
topic transformer
GRU
sensor fusion
Kalman filter
trajectory prediction
orchard navigation
url https://www.mdpi.com/2077-0472/15/11/1135
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AT jinzhenfang grutransformerhybridmodelforgnssinsintegrationinorchardenvironments
AT junlinhe grutransformerhybridmodelforgnssinsintegrationinorchardenvironments
AT shuangma grutransformerhybridmodelforgnssinsintegrationinorchardenvironments
AT guanghuawen grutransformerhybridmodelforgnssinsintegrationinorchardenvironments
AT zhenli grutransformerhybridmodelforgnssinsintegrationinorchardenvironments