A Real-Time Orbit Determination Method for Smooth Transition from Optical Tracking to Laser Ranging of Debris

Abstract Background and study aims The aim of this study was to introduce EndoConf, a reliable and easy-to-use tool capable of optimizing clinical care in endoscopy by reducing the number of repeat endoscopy procedures, providing continuous on-the-job clinical education, and allowing a smooth transition to the next level of artificial intelligence-supported systems. Patients and methods We prospectively developed and improved a real-time conference system (EndoConf). EndoConf enables endoscopists to contact on-demand and in real time experienced endoscopists across other sites. After the initial introduction period, we registered all EndoConf-assisted procedures from our unit (Surgical Department of Odense University Hospital) over a 3-month period (Autumn of 2019). Results Of 84 EndoConf-supported procedures, 58 were eligible for further analysis. Eventually, 38 calls were made, of which only four were technically of low quality (10.5 %) while three were not answered (7.9 %). Of the 35 (92.1 %) completed EndoConf calls; 24 were referred for endoscopic mucosal resection, six were referred for transanal microsurgery preceded by transrectal ultrasonography and three were referred for multidisciplinary conference, whereas in two cases, the lesion was resected during EndoConf. Conclusions We found the EndoConf system to provide support that could reduce the number of unnecessary repeat endoscopic procedures while at the same time ensuring avoidance of any hazardous attempt at polypectomy.

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Precise Real-Time Relative Orbit Determination for Large-Baseline Formations Using GNSS

Proceedings of the 2021 International Technical Meeting of The Institute of Navigation ◽

10.33012/2021.17839 ◽

2021 ◽

Author(s):

Vincent Giralo ◽

Simone D’Amico

Keyword(s):

Real Time ◽

Orbit Determination ◽

Relative Orbit

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Design of Laser Ranging Device Using the Improved Photodetector and Its Usage in Geosynchronous Earth Orbit Navigation Satellite Orbit Determination

Journal of Nanoelectronics and Optoelectronics ◽

10.1166/jno.2020.2900 ◽

2020 ◽

Vol 15 (12) ◽

pp. 1508-1517

Author(s):

Xiangfei Yin ◽

Genyou Liu ◽

Shilong Cao

Keyword(s):

Orbit Determination ◽

Silicon Substrate ◽

Structural Parameters ◽

Fdtd Method ◽

Absorption Enhancement ◽

Laser Ranging ◽

Earth Orbit ◽

Geo Satellites ◽

Msm Photodetector ◽

Regional Augmentation

The geosynchronous earth orbit (GEO) satellites have good coverage performance and are widely used in WAAS, BDS, CAPS and other regional augmentation and regional navigation systems. At the same time, the precise orbit determination and prediction of such satellites play a significant role in high-precision navigation and user real-time positioning. In order to obtain higher accuracy of orbit determination, the laser ranging device is improved by equipping with a silicon-substrate germanium MSM photodetector in this study. In addition, the surface plasmon resonance augmentation effect is further studied to further enhance the photoelectric performance of the silicon-substrate germanium MSM photodetector. The detector is connected to the OPA657. The corresponding pre-amplified circuit is further designed in this study so that the laser ranging device can be used for the orbit determination application of GEO navigation satellites. In the experiment, the designed silicon-substrate germanium MSM photodetector is tested firstly, the finite-different time-domain (FDTD) method is used to analyze the structure of the photodetector. Then, the effects of the structural parameters such as the grating period on the resonance augmentation of the designed photodetector are analyzed. The results reveal that the photodetector has the best performance at 1500 nm with the absorption enhancement factor of higher than 7. The GNSS combined with the laser ranging is used for comparing the orbit determination errors of GEO satellites. 10 laser observation stations are selected, some of which are equipped with the laser ranging device designed in this study and supply to various GEO satellites for information collection. The results show that GEO satellites have to be introduced to the system deviation when adding the laser ranging data, otherwise they will deviate from the orbit. In addition, the laser ranging device designed in this study can significantly reduce the deviation caused by the introduction of laser ranging data from GEO satellites compared with traditional laser ranging devices.

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