Aiming at the requirement of low cost, high precision and high stability of space advanced technology demonstration satellite, a method of heterogeneous backup of attitude control sensor is proposed, and the design principle of the sensor is analyzed in depth multi-sensor information fusion algorithm is designed. The control strategy of the satellite is optimized, the weighted PID control strategy is designed, and a reasonable integral separation threshold is selected. Control bandwidth is adjusted to reduce the control deviation caused by time delay. The objective of the attitude control system is to achieve control accuracy better than 0.1°(3σ) and control stability better than 0.003°/s(3σ).Through the analysis of on-orbit test data, the control accuracy of the satellite is better than 0.005°(3σ), and the control stability is better than 0.0005°/s(3σ).
The Large Area Detector (LAD) is the high-throughput, spectral-timing instrument onboard the eXTP mission, a flagship mission of the Chinese Academy of Sciences and the China National Space Administration, with a large European participation coordinated by Italy and Spain. The eXTP mission is currently performing its phase B study, with a target launch at the end-2027. The eXTP scientific payload includes four instruments (SFA, PFA, LAD and WFM) offering unprecedented simultaneous wide-band X-ray timing and polarimetry sensitivity. The LAD instrument is based on the design originally proposed for the LOFT mission. It envisages a deployed 3.2 m2 effective area in the 2-30 keV energy range, achieved through the technology of the large-area Silicon Drift Detectors - offering a spectral resolution of up to 200 eV FWHM at 6 keV - and of capillary plate collimators - limiting the field of view to about 1 degree. In this paper we will provide an overview of the LAD instrument design, its current status of development and anticipated performance.
Space environment above Quasi-equatorial ground has an advantage of relative quietness and friendliness. It is preferred to deploy satellites of demanding stability and longer lifespan. For these satellites, the communication via VHF between ground stations and satellites has become one of the difficulties when it comes to the satellite engineering. To make a quantitative assessment, the satellite VHF coverage of ground stations are carried out for two typical orbits, of which the altitude are roughly 500km and 550km,and the inclination is 2.5 deg. Ground stations for VHF communication include the 88 stations, which are distributed along the belt with latitude less than +/-30deg. The cutoff angles for VHF communication are 10 deg. Two antenna for communication are fixed in the satellite body along +Z axis and –Z axis respectively, and the half beam angle of the boresight is 90 deg. Simulations of satellites based VHF coverage of 88 ground stations are carried out. During case 1, satellite orbit altitude is assumed to be 500km,and inclination is 2.5 deg. For case 2, satellite orbit altitude is assumed to be 550km,and inclination is 2.5 deg. Satellite-based VHF coverages of 88 ground stations are 63.3% for case 1,and 66.5% for case 2. For case 1, yearly VHF communication opportunities are 34594 times. Average duration is 576 seconds. Daily VHF communication opportunities are 95 times. Daily available communication interval is 912 minutes. The unavailable time interval is 28.2 minutes. For case 2, yearly VHF communication opportunities are 29161 times. Average duration is 718 seconds. Daily VHF communication opportunities are 80 times. Daily available communication interval is 957 minutes. The unavailable time interval is 26.4 minutes. Case 1 is preferred if satellite engineering demands more quiet space environment. Case 2 is preferred if satellite engineering demands longer lifespan and better coverage. It is suggested that case 2 be a good choice for space science mission devoted to observe astronomical events in remote space.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.