Changchun Human Satellite Observatory Completes Verification Of Limit Detection Indicators On Jilin 1.2m Near-Infrared Non-Cooperative Target Laser Ranging Platform

On January 28, 2024, the Changchun Artificial Satellite Observatory (CASO), Changchun Institute of Optical Precision Machinery and Physics (CIPMP), and Institute of Space Information Innovation (ISI) jointly carried out the verification experiment of the limit detection index of non-cooperative targets on the newly constructed 1.2m near-infrared laser ranging platform in Jilin, and successfully obtained the weak laser ranging echoes of a non-cooperative target (NORAD No.: 00900). After processing, the effective data arc length is 1 minute and 15 seconds, the number of effective data points is 47, and the minimum size of the equivalent 1000km target is 0.1174m, which meets the requirements of the laser detection limit index of the non-cooperative target of the 1.2m near-infrared laser ranging system, and the experimental validation of the limit detection index has been successfully completed.
NORAD No. 00900 target launched in October 1964, the U.S. Air Force microsatellite (radar calibration ball), the name CALSPHERE 1. The target is a diameter of 14 inches (35.6cm) of polished aluminum hollow sphere, the mass of 0.98kg (the target shape of the data source: Siegfried W. Janson, "Micro /" Nanotecnology for Picicosat. Nanotecnology for Picosatellites"), which was designed for a polar orbit at an altitude of 1000 km, was used as a radar target and as a calibration target for the Atmospheric Density Monitor (ADM), where the orbit tracking data could be used to determine the satellite drag level, and thus the relationship between atmospheric density and altitude. The weather conditions on that day were good, and the target was visible in the short-wave guide star camera. The observation period was from 10:55 to 1:59 UTC on January 28, 2024, and the maximum pitch angle of the target in the observation arc was 63.5°, and the minimum visible pitch angle was 21.7°.
The detection of small-size non-cooperative targets puts forward extremely high requirements and great challenges for the telescope tracking and pointing accuracy of the ranging system, the single-photon detection sensitivity of the detector, the distance gating time accuracy, the monitoring and tracking of the dark and weak space debris targets, the beam quality of the laser as well as the transceiver-optical axis parallelism, etc. At present, China has made great efforts in the important on-orbit application of the telescope. At present, China conducts space debris monitoring on important in-orbit application satellites, and there is an urgent need to build a high-precision space debris monitoring network in China. Changchun Human Health Station, in cooperation with Changchun Institute of Optical Mechanics and Space Academy, has jointly undertaken the development of the 1.2m near-infrared laser ranging platform system deployed in Jilin. The development units give full play to their respective leading advantages and long-term technical accumulation in the development of telescope system, range control software and hardware development, non-cooperative target ranging, high-power laser development and other aspects of technology. The 1.2m near-infrared laser ranging system completed in July 2023 has passed the overall testing and evaluation of the system, and is now in the initial operation stage of the system. The successful detection of this limit indicator fully verifies the laser detection capability of the 1.2m near-infrared laser ranging system constructed by the Institute for small-size dark and weak non-cooperative targets, which is of great significance for the construction of a ground-based high-precision laser monitoring network for space debris in China and will also play a positive role in promoting applied research on high-precision orbital cataloguing of space debris targets in low-orbit, early warning of collision and precision orbit determination.