Realizing the Calculation of a Fully Normalized Associated Legendre Function Based on an FPGA

A large number of fully normalized associated Legendre function (fnALF) calculations are required to compute Earth’s gravity field elements using ultra high-order gravity field coefficient models. In the surveying and mapping industry, researchers typically rely on CPU-based systems for these calcul...

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Main Authors: Yuxiang Fang, Qingbin Wang, Yichao Yang
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Sensors
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Online Access:https://www.mdpi.com/1424-8220/24/22/7262
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author Yuxiang Fang
Qingbin Wang
Yichao Yang
author_facet Yuxiang Fang
Qingbin Wang
Yichao Yang
author_sort Yuxiang Fang
collection DOAJ
description A large number of fully normalized associated Legendre function (fnALF) calculations are required to compute Earth’s gravity field elements using ultra high-order gravity field coefficient models. In the surveying and mapping industry, researchers typically rely on CPU-based systems for these calculations, which leads to limitations in execution speed and power efficiency. Although modern CPUs improve instruction execution efficiency through instruction-level parallelism, the constraints of a shared memory architecture impose further limitations on the execution speed and power efficiency. This results in exponential increases in computation time as demand rises alongside high power consumption. In this article, we present a new computational implementation of an fnALF based on the ZYNQ platform. We design a task-parallel “pipeline” architecture which converts the original serial logic into a more efficient hardware implementation, and we utilize a redundant calculation layer to handle repetitive coefficient computations separately. The experimental results demonstrate that our system achieved accurate and rapid calculations. Under the only one geocentric residual latitude condition, we measured the computation times for spherical harmonic coefficient degrees of 360, 720, and 1080 to be 0.155922 s, 0.520950 s, and 1.401609 s, respectively. In the case of the multiple geocentric residual latitudes condition, our design generally yielded efficiency gains of over three times those of MATLAB R2020b implementation. Additionally, our calculated results were used to determine the geoid height in the field with an error of less than <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>±</mo><mn>0.1</mn><mspace width="0.166667em"></mspace><mi mathvariant="normal">m</mi></mrow></semantics></math></inline-formula>, confirming the reliability of our computations.
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spelling doaj-art-51d280dea4464bbfa0f01194355c347a2025-08-20T01:53:57ZengMDPI AGSensors1424-82202024-11-012422726210.3390/s24227262Realizing the Calculation of a Fully Normalized Associated Legendre Function Based on an FPGAYuxiang Fang0Qingbin Wang1Yichao Yang2School of Information and Electronic Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, ChinaSchool of Information and Electronic Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, ChinaSchool of Information and Electronic Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, ChinaA large number of fully normalized associated Legendre function (fnALF) calculations are required to compute Earth’s gravity field elements using ultra high-order gravity field coefficient models. In the surveying and mapping industry, researchers typically rely on CPU-based systems for these calculations, which leads to limitations in execution speed and power efficiency. Although modern CPUs improve instruction execution efficiency through instruction-level parallelism, the constraints of a shared memory architecture impose further limitations on the execution speed and power efficiency. This results in exponential increases in computation time as demand rises alongside high power consumption. In this article, we present a new computational implementation of an fnALF based on the ZYNQ platform. We design a task-parallel “pipeline” architecture which converts the original serial logic into a more efficient hardware implementation, and we utilize a redundant calculation layer to handle repetitive coefficient computations separately. The experimental results demonstrate that our system achieved accurate and rapid calculations. Under the only one geocentric residual latitude condition, we measured the computation times for spherical harmonic coefficient degrees of 360, 720, and 1080 to be 0.155922 s, 0.520950 s, and 1.401609 s, respectively. In the case of the multiple geocentric residual latitudes condition, our design generally yielded efficiency gains of over three times those of MATLAB R2020b implementation. Additionally, our calculated results were used to determine the geoid height in the field with an error of less than <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>±</mo><mn>0.1</mn><mspace width="0.166667em"></mspace><mi mathvariant="normal">m</mi></mrow></semantics></math></inline-formula>, confirming the reliability of our computations.https://www.mdpi.com/1424-8220/24/22/7262associated Legendre functiongravity fieldrecursive algorithmFPGA
spellingShingle Yuxiang Fang
Qingbin Wang
Yichao Yang
Realizing the Calculation of a Fully Normalized Associated Legendre Function Based on an FPGA
Sensors
associated Legendre function
gravity field
recursive algorithm
FPGA
title Realizing the Calculation of a Fully Normalized Associated Legendre Function Based on an FPGA
title_full Realizing the Calculation of a Fully Normalized Associated Legendre Function Based on an FPGA
title_fullStr Realizing the Calculation of a Fully Normalized Associated Legendre Function Based on an FPGA
title_full_unstemmed Realizing the Calculation of a Fully Normalized Associated Legendre Function Based on an FPGA
title_short Realizing the Calculation of a Fully Normalized Associated Legendre Function Based on an FPGA
title_sort realizing the calculation of a fully normalized associated legendre function based on an fpga
topic associated Legendre function
gravity field
recursive algorithm
FPGA
url https://www.mdpi.com/1424-8220/24/22/7262
work_keys_str_mv AT yuxiangfang realizingthecalculationofafullynormalizedassociatedlegendrefunctionbasedonanfpga
AT qingbinwang realizingthecalculationofafullynormalizedassociatedlegendrefunctionbasedonanfpga
AT yichaoyang realizingthecalculationofafullynormalizedassociatedlegendrefunctionbasedonanfpga