TY  - JOUR
A1  - Wang, Xiaoliang
A1  - Liu, Xuan
A1  - Xiao, Yun
A1  - Mao, Yue
A1  - Wang, Nan
A1  - Wang, Wei
A1  - Wu, Shufan
A1  - Song, Xiaoyong
A1  - Wang, Dengfeng
A1  - Zhong, Xingwang
A1  - Zhu, Zhu
A1  - Schilling, Klaus
A1  - Damaren, Christopher
T1  - On-orbit verification of RL-based APC calibrations for micrometre level microwave ranging system
JF  - Mathematics
N2  - Micrometre level ranging accuracy between satellites on-orbit relies on the high-precision calibration of the antenna phase center (APC), which is accomplished through properly designed calibration maneuvers batch estimation algorithms currently. However, the unmodeled perturbations of the space dynamic and sensor-induced uncertainty complicated the situation in reality; ranging accuracy especially deteriorated outside the antenna main-lobe when maneuvers performed. This paper proposes an on-orbit APC calibration method that uses a reinforcement learning (RL) process, aiming to provide the high accuracy ranging datum for onboard instruments with micrometre level. The RL process used here is an improved Temporal Difference advantage actor critic algorithm (TDAAC), which mainly focuses on two neural networks (NN) for critic and actor function. The output of the TDAAC algorithm will autonomously balance the APC calibration maneuvers amplitude and APC-observed sensitivity with an object of maximal APC estimation accuracy. The RL-based APC calibration method proposed here is fully tested in software and on-ground experiments, with an APC calibration accuracy of less than 2 mrad, and the on-orbit maneuver data from  11–12 April 2022, which achieved 1–1.5 mrad calibration accuracy after RL training. The proposed RL-based APC algorithm may extend to prove mass calibration scenes with actions feedback to attitude determination and control system (ADCS), showing flexibility of spacecraft payload applications in the future.
KW  - reinforcement learning
KW  - antenna phase center calibration
KW  - K band ranging (KBR)
KW  - micrometre level microwave ranging
KW  - MSC: 49M37
KW  - MSC: 65K05
KW  - MSC: 90C30
KW  - MSC: 90C40
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-303970
SN  - 2227-7390
VL  - 11
IS  - 4
ER  - 
TY  - JOUR
A1  - Song, Ning-Ning
A1  - Jia, Yun-Fang
A1  - Zhang, Lei
A1  - Zhang, Qiong
A1  - Huang, Ying
A1  - Liu, Xiao-Zhen
A1  - Hu, Ling
A1  - Lan, Wei
A1  - Chen, Ling
A1  - Lesch, Klaus-Peter
A1  - Chen, Xiaoyan
A1  - Xu, Lin
A1  - Ding, Yu-Qiang
T1  - Reducing central serotonin in adulthood promotes hippocampal neurogenesis
JF  - Scientific Reports
N2  - Chronic administration of selective serotonin reuptake inhibitors (SSRIs), which up-regulates central serotonin (5-HT) system function, enhances adult hippocampal neurogenesis. However, the relationship between central 5-HT system and adult neurogenesis has not fully been understood. Here, we report that lowering 5-HT level in adulthood is also able to enhance adult hippocampal neurogenesis. We used tamoxifen (TM)-induced Cre in Pet1-CreER\(^{T2}\) mice to either deplete central serotonergic (5-HTergic) neurons or inactivate 5-HT synthesis in adulthood and explore the role of central 5-HT in adult hippocampal neurogenesis. A dramatic increase in hippocampal neurogenesis is present in these two central 5-HT-deficient mice and it is largely prevented by administration of agonist for 5-HTR2c receptor. In addition, the survival of new-born neurons in the hippocampus is enhanced. Furthermore, the adult 5-HT-deficient mice showed reduced depression-like behaviors but enhanced contextual fear memory. These findings demonstrate that lowering central 5-HT function in adulthood can also enhance adult hippocampal neurogenesis, thus revealing a new aspect of central 5-HT in regulating adult neurogenesis.
KW  - serotonin
KW  - SSRI
KW  - hippocampal neurogenesis
KW  - adulthood
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-168004
VL  - 6
IS  - 20338
ER  -