Simulation and Prediction for a Satellite Temperature Sensors Based on Artificial Neural Network

Abstract

Spacecrafts in the space environment are exposed to several kinds of thermal sources such as radiation, albedo and emitted IR from the earth. The thermal control subsystem in the spacecraft is used to keep all parts operating within allowable temperature ranges. A failure in one or many temperature sensors could lead to an abnormal operation. Consequently, a prediction process must be performed to replace the missing data with estimated values to prevent abnormal behavior. The goal of the proposed model is to predict the failed or missing sensor readings based on artificial neural networks (ANN). It has been applied to EgyptSat-1 satellite. A backpropagation algorithm called Levenberg-Marquardt is used to train the neural networks (NN). The proposed model has been tested by one and two hidden layers. Practical metrics such as mean square error, mean absolute error and the maximum error are used to measure the performance of the proposed network. The results showed that the proposed model predicted the values of one failed sensor with adequate accuracy. It has been employed for predicting the values of two failed sensors with an acceptable mean square and mean absolute errors; whereas the maximum error for the two failed sensors exceeded the acceptable limits.

Keywords

• Artificial neural networks
• Thermal control subsystem
• Thermal control simulation
• Sensor values prediction
• Levenberg-Marquardt algorithm