# On-Board Parameter Optimization for Space-Based Infrared Air Vehicle Detection Based on ADS-B Data
## 3 Results and Discussion
### On-Board Spectral Band Optimization  
The spectral band optimization results of \(SCR\) are shown in Figure 7. The extreme value was obtained near the 2.6-2.8 \(\upmu\)m absorption band, and they were all higher than 100, except the daytime cirrus cloud background. The \(SCR\) value in (c) was the lowest; therefore, it was the most difficult to detect the target, and \(SCR\) obtained a peak value at 2.8 \(\upmu\)m, which was above 60. According to the \(SCR\) threshold discussed in the previous section, it can be seen that most of the spectral bands selected based on the target and background contrast met \(SCR\) greater than 10, and the specific spectral band should be further determined by combining camera \(SNR\) to achieve \(JSNCR\). As shown in Figure 8, the spectral band optimization results of \(SNR\) show that the value varied greatly in different backgrounds and that there was no uniform trend, but the \(SNR\) was higher during the daytime than the nighttime. It was noted that SNR had a negative value under some nighttime conditions, which indicated that the energy of the air target was lower than that of the night background, showing a negative contrast. The optimal spectrum segment should be determined according to the \(SNR\) threshold value and combined with \(SCR\) using \(JSNCR\) as the final criterion. \begin{table}
\begin{tabular}{c c c} \hline
**Parameter** & **Fixed Parameter** & **Proposed** \\ \hline Orbit altitude & 36,000 km & 36,000 km \\ \hline Optical aperture & 2.3 m & 2.3 m \\ \hline \(GSD\) & 70 m & 70 m \\ \hline Detection band & 2.7–3.0 \(\upmu\)m & 2.0–4.5 \(\upmu\)m, \\  & (fixed) & Dynamically adjustable \\ \hline Integration time & 100 ms (daytime), 200 ms (nighttime) & 10 \(\upmu\)s–1000 ms, \\  & 200 ms (nighttime) & Dynamically adjustable \\ \hline Integration capacitance gear & \(3\times 10^{6}\) e\({}^{-}\), \(6\times 10^{6}\) e\({}^{-}\) & \(3\times 10^{6}\) e\({}^{-}\), \(6\times 10^{6}\) e\({}^{-}\), \\ (full well) & (default \(3\times 10^{6}\) e\({}^{-}\)) & Dynamically adjustable \\ \hline \end{tabular}
\end{table} 
Table 1: Space-based AVD system parameters. Figure 7: The spectral band optimization results of \(SCR\) with different backgrounds. (**a**) Daytime cumulus cloud; (**b**) daytime altostatus cloud; (**c**) daytime cirrus cloud; (**d**) daytime sea; (**e**) nighttime cumulus cloud; (**f**) nighttime alostratus cloud; (**g**) nighttime cirrus cloud; (**h**) nighttime sea. Based on ADS-B data, the optimization spectrum band results of the four types of background through \(JSNCR\) are shown in Figure 9. It can be seen that in (a) and (b) the background optimization results of cumulus and altostratus were similar, and  
Figure 8: The spectral band optimization results of \(SNR\) with different backgrounds. (**a**) Daytime cumulus cloud; (**b**) daytime altostratus cloud; (**c**) daytime cirrus cloud; (**d**) daytime sea; (**e**) nighttime cumulus cloud; (**f**) nighttime altostratus cloud; (**g**) nighttime cirrus cloud; (**h**) nighttime sea. the highest performance was obtained in the 2.822-3.244 \(\upmu\)m range under the cumulus cloud background, which was about two times that of the fixed-parameter system; the altostratus cloud background obtained the highest \(JSNCR\) in the 2.787-3.287 \(\upmu\)m range, about 1.7 times the detectability of the fixed-parameter system; the optimized spectral band of the cirrus cloud background in (c) was 2.842-3.112 \(\upmu\)m, and the performance was significantly improved after spectrum optimization, which was more than six times higher than that of the fixed-parameter system; 2.45-2.95 \(\upmu\)m under the background of the sea was the optimal detection band in (d), and the \(JSNCR\) was about two times that of the fixed-parameter system. Combining the common parts of (a), (b) and (c) intervals, taking 2.8-3.2 \(\upmu\)m as the common detection band interval can meet all cloud marine background detection requirements.