The long-wave infrared (LWIR) quantum-well photodetector (QWIP) operates at low temperatures, but is prone to focal plane temperature changes when imaging in complex thermal environments. This causes dark current changes and generates low-frequency temporal dark current noise. To address this, a dark current noise correction method based on dark pixels is proposed. First, dark pixels were constructed in a QWIP system and the response components of imaging pixels and dark pixels were analyzed. Next, the feature data of dark pixels and imaging pixels were collected and preprocessed, after which a recurrent neural network (RNN) was used to fit the dark current response model. Target data were collected and input into the dark current response model to obtain dark level correction values and correct the original data. Finally, after calculation and correction, temporal noise was reduced by 49.02% on average. The proposed method uses the characteristics of dark pixels to reduce dark current temporal noise, which is difficult using conventional radiation calibrations; this is helpful in promoting the application of QWIPs in LWIR remote sensing.

An active optical system with three segmented mirrors was proposed to verify the co-focus and co-phase progress. In this system, a kind of large-stroke and high-precision parallel positioning platform was specially developed to help support the mirrors and reduce the error between them, which can move in three degrees of freedom out of plane. The positioning platform was composed of three flexible legs and three capacitive displacement sensors. For the flexible leg, a kind of forward-type amplification mechanism was specially designed to amplify the displacement of the piezoelectric actuator. The output stroke of the flexible leg was no less than 220 μm and the step resolution was up to 10 nm. Further, a linear model was established to identify the amplification ratio between the actuator and the flexible leg, which can increase the precision of the positioning platform. Moreover, three capacitive displacement sensors with a resolution of 2.5 nm were symmetrically installed in the platform to accurately measure the position and attitude of the platform. To improve the stability and precision of the platform, particle swarm optimization algorithm was applied to identify the control matrix, which can help the platform achieve ultra-high precision positioning. The results showed that the theoretical matrix parameters had a maximum deviation of 5.67% from the experimental ones. Finally, abundant experiments verified the excellent and stable performance of the platform. The results proved that while bearing the heavy mirror, which is no more than 5 kg, the platform can realize a 220 μm translation stroke and 2.0 mrad deflection stroke, with a high step resolution of 20 nm and 0.19 μrad. These indicators can perfectly cater to the requirements of the proposed segmented mirror system’s co-focus and co-phase adjustment progress.

The performance of long-wave infrared (LWIR) quantum well (QWIP) detection systems is seriously affected by the dark current of the detectors. Tiny variations in the focal-plane temperature of the devices cause fluctuations in the dark current, which in turn generate temporal noise. It is difficult to measure the dark current accurately after the detector assembly is packaged. To address the above problems, a QWIP dark current measurement method based on focal-plane temperature is proposed, as well as a method to reduce dark current noise. First, the response model of the LWIR QWIP detection system was established, and the dark current model was introduced. Then, the detection system components were introduced, chiller calibration experiments were carried out, and the dark current values of the QWIP at different temperatures were measured by combining the system design and parameters. Next, the dark current noise correction method was proposed, the target data were collected, and experiments were carried out to correct them. Finally, after the calculation, the temporal noise was reduced by 57.69% after the correction, which is proof of a significant effect. This method can obtain the real-time dark current value by collecting the focal-plane temperature data, and reduce the dark current temporal noise (difficult to eliminate using conventional methods), which is beneficial for promoting the application of QWIPs in LWIR remote sensing detection.

The coupling relationship between space electronics systems is complex, and the signals of optoelectronic load cables are susceptible to interference, especially the early anomalous weak signals on a ground surface used for immediate remote sensing, which are more susceptible to coupling interference between cables. Ensuring a good grounding state for the cable shield is vital for reducing the interference suffered by cables and increasing the electromagnetic compatibility of the system. In this paper, we propose a shielding grounding optimization method for a spaceborne multi-cable shield, including a cable model and parameter extremization and parameter scanning simulation performed using CST, data processing and truth table transformation conducted using MATLAB, and logic expression extraction carried out using Multisim. The method can sort and classify the shielding effects of all the grounding states of multi-cable shields in batches, and ultimately output logical expressions specifying the mapping relationship between the shield grounding state and shielding effect, allowing the optimal shield grounding state to be quickly identified. Finally, the method was applied to a satellite-borne scanning mirror drive control system, and the effectiveness and accuracy of the method were verified by experimental tests.