Improved Sun Glint Computational Model Based on WGS-84 Ellipsoid and Simulation Analysis

Chunjie Dai; Aiming Zhou; Yi Yang; Dongdong Zhang

doi:10.3788/LOP223050

Journals >Laser & Optoelectronics Progress >Volume 60 >Issue 20 >Page 2001001 > Article

Laser & Optoelectronics Progress
Vol. 60, Issue 20, 2001001 (2023)

Improved Sun Glint Computational Model Based on WGS-84 Ellipsoid and Simulation Analysis

Chunjie Dai¹, Aiming Zhou², Yi Yang¹, and Dongdong Zhang^1、*

Author Affiliations

¹Key Laboratory of Infrared System Detection and Imaging Technologies, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China

²Shanghai Institute of Satellite Engineering, Shanghai 200240, China

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DOI: 10.3788/LOP223050 Cite this Article Set citation alerts

Chunjie Dai, Aiming Zhou, Yi Yang, Dongdong Zhang. Improved Sun Glint Computational Model Based on WGS-84 Ellipsoid and Simulation Analysis[J]. Laser & Optoelectronics Progress, 2023, 60(20): 2001001 Copy Citation Text

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Abstract

The sun glint observation mode is adopted when a satellite payload detects greenhouse gases over the ocean to obtain high-precision gas concentration data. Therefore, accurately calculating the real-time sun glint position is a prerequisite for obtaining high-precision data. An improved sun glint calculation model based on an optimal line search is proposed. According to the WGS-84 ellipsoid model, on the basis of dichotomy searching to meet the requirements of specular reflective speckles, the algorithm is improved by using the idea of optimal line search to better meet the coplanar condition of the sun glint. Compared with the simulation results of the Satellite Tool Kit (STK), the sun glint position distance error calculated by the improved model is significantly reduced to 90 m.

Keywords

dichotomy greenhouse gas line search sun glint WGS-84 ellipsoid

r_{g l i n t} = R_{e} \cdot A (C, α) \cdot {\hat{r}}_{s u n}

，（1）

A (C, α) = [\begin{matrix} c o s α + e_{x}^{2} (1 - c o s α) & e_{x} e_{y} (1 - c o s α) - e_{z} s i n α & e_{x} e_{z} (1 - c o s α) + e_{y} s i n α \\ e_{x} e_{y} (1 - c o s α) + e_{z} s i n α & c o s α + e_{y}^{2} (1 - c o s α) & e_{y} e_{z} (1 - c o s α) - e_{x} s i n α \\ e_{x} e_{z} (1 - c o s α) - e_{y} s i n α & e_{y} e_{z} (1 - c o s α) + e_{x} s i n α & c o s α + e_{z}^{2} (1 - c o s α) \end{matrix}]

，（2）

c o s φ = \sqrt[]{x^{2} + y^{2}}

，（3）

t a n φ = \frac{z}{\sqrt[]{x^{2} + y^{2}}}

，（4）

t a n B = \frac{t a n φ}{1 - e^{2}}

，（5）

R_{e} = \frac{1}{c o s φ} \cdot \frac{a^{2}}{\sqrt[]{a^{2} + {(b \cdot t a n B)}^{2}}}

，（6）

N = [\begin{matrix} \frac{x}{a^{2}} & \frac{y}{a^{2}} & \frac{z}{b^{2}} \end{matrix}]

，（7）

D = {\hat{r}}_{g l i n t} \times C

，（8）

{\hat{r}}_{g l i n t}^{'} = R_{e} \cdot A (D, θ) \cdot {\hat{r}}_{g l i n t}

，（9）

C^{'} = r_{s u n} \times (r_{s a t} - r_{g l i n t}^{'})

，（10）

φ = a r c s i n \frac{N^{'} \cdot C^{'}}{|N^{'}| \cdot |C^{'}|}

，（11）

r_{g l i n t 2} = R_{o i} \cdot r_{g l i n t}^{'} + [\begin{matrix} 0 \\ 0 \\ R_{s} \end{matrix}]

，（12）

r_{g l i n t 3} = R_{y} (θ) R_{x} (φ) R_{z} (ψ) \cdot r_{g l i n t 2}

，（13）

R_{x} = [\begin{matrix} 1 & 0 & 0 \\ 0 & c o s φ & s i n φ \\ 0 & - s i n φ & c o s φ \end{matrix}]

，

R_{y} = [\begin{matrix} c o s θ & 0 & - s i n θ \\ 0 & 1 & 0 \\ s i n θ & 0 & c o s θ \end{matrix}]

，

R_{z} = [\begin{matrix} c o s ψ & s i n ψ & 0 \\ - s i n ψ & c o s ψ & 0 \\ 0 & 0 & 1 \end{matrix}]

。（14）

θ = - a r c s i n \frac{- N_{x}}{|Ν|} = a r c s i n \frac{x - 1}{\sqrt[]{{(x - 1)}^{2} + y^{2} + z^{2}}}

。（15）

φ = a r c s i n \frac{- N_{x}}{|Ν'|} = a r c s i n \frac{- y}{\sqrt[]{y^{2} + z^{2}}}

。（16）

Chunjie Dai, Aiming Zhou, Yi Yang, Dongdong Zhang. Improved Sun Glint Computational Model Based on WGS-84 Ellipsoid and Simulation Analysis[J]. Laser & Optoelectronics Progress, 2023, 60(20): 2001001

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