Construction and Accuracy Analysis of a BDS/GPS-Integrated Positioning Algorithm for Forests

Fei Yan,Yongrui Wu,Xueqi Hu,Lidan Xu

doi:10.5552/crojfe.2021.1105

Fei Yan, Yongrui Wu + Show 2 more

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https://doi.org/10.5552/crojfe.2021.1105

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Abstract

The objective of this study was to construct a BeiDou navigation satellite system (BDS)/global positioning system (GPS)-integrated positioning algorithm that meets the accuracy requirement of forest surveys and to analyze its accuracy to provide theoretical and technical support for accurate positioning and navigation in forests. The Quercus variabilis broad-leaved forest in Jiufeng National Forest Park and the Sabina Coniferous forest in Dongsheng Bajia forest farm were selected as the study area. A Sanding T-23 multi-frequency three-constellation receiver and a u-blox NEO-M8T multi-constellation receiving module were used for continuous observation under the forest canopy. Compared with T-23, the u-blox NEO-M8T is much lighter and more flexible in the forest. The BDS/GPS-integrated positioning algorithm for forests was constructed by temporally and spatially unifying the satellite systems and using a reasonable observed value weighting method. Additionally, the algorithm is also written into the RTKLIB software to calculate the three-dimensional (3D) coordinates of the forest observation point in the World Geodetic System 1984 (WGS-84) coordinate system. Finally, the results were compared with the positioning results obtained using GPS alone. The experimental results indicated that, compared with GPS positioning, there were 13–27 visible satellites available for the BDS/GPS-integrated positioning algorithm for forests, far more than the satellites available for the GPS positioning algorithm alone. The Position Dilution of Precision (PDOP) values for the BDS/GPS-integrated positioning ranged from 0.5 to 1.9, lower than those for GPS positioning. The signal noise ratio (SNR) of the BDS/GPS-integrated satellite signals and GPS satellite signals were both in the range of 10–50 dB-Hz. However, because there were more visible satellites for the BDS/GPS-integrated positioning, the signals from the BDS/GPS-integrated satellites were stronger and had a more stable SNR than those from the GPS satellites alone. The results obtained using the BDS/GPS-integrated positioning algorithm for forests had significantly higher theoretical and actual accuracies in the X, Y and Z directions than those obtained using the GPS positioning algorithm. This suggests that the BDS/GPS-integrated positioning algorithm can obtain more accurate positioning results for complex forest environments.

Highlights

Forestry, as a principal part of ecological civilization construction, plays important ecological, economic, social and cultural roles
The number of visible satellites (NVS) that could be observed during the whole period of positioning under the forest canopy and the corresponding signal quality were recorded using the RTKLIB software
In the broad-leaved forest area, for the BeiDou navigation satellite system (BDS)/global positioning system (GPS)-integrated positioning algorithm, there was a total of 15–23 satellites available for positioning and observation during the observation period, including GPS satellites and BDS satellites (Figs. 4 a and b)

Summary

Introduction

As a principal part of ecological civilization construction, plays important ecological, economic, social and cultural roles. To better realize the functions of forestry, maintain healthy development of forests and informatize forest management, precision is of particular importance. Global navigation satellite systems (GNSS) play a tremendous role in fine forest. GNSS can provide realtime, accurate positioning information, occurrence area information and navigation services for core forestry operations, such as forest resource surveys, forest fire prevention and emergency planning, and plant disease and insect pest monitoring, prevention and control. GNSS are a central topic in global forest survey research (Bettinger et al 2019, Becker et al 2017, Brach et al 2014, Liu et al 2017). Construction and Accuracy Analysis of a BDS/GPS-Integrated Positioning Algorithm for Forests (321–335)

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