Research on the visibility of low-orbit debris using space-borne radar

Space debris with size larger than 1 cm poses a threat to spacecraft. Recently, space debris surveillance, tracking and early warning become far more urgent than ever before owing to the explosive growth of the number of debris. At the base of these problems is how to determine the visibility of debris to observation equipment, which will be discussed in this study. The statistics related to the orbital altitude, inclination and eccentricity of space debris are presented first, and then the principles of orbital parameter design of the space-borne radar (SBR) are given. Next, systemic parameters of SBR, such as wavelength, antenna type, are determined upon the observation aim. Detectable debris subset is preliminarily selected in accordance with some constraints. At last, based on the simplified general perturbations (SGP4) model, the range and velocity vectors of debris to SBR at specific time are calculated. Another expression form of relative position between debris and radar, range, azimuth and elevation (RAE) course is obtained by means of coordinate rotation which can be accomplished by directing projection or rotational matrix. The RAE data guide file can be used to carry on guidance tracking. Furthermore, the conversion accuracy of two different coordinate transformation methods is also analysed.