Optimal constellation design of low earth orbit (LEO) EO/IR sensor platforms for space situational awareness

2009 ◽  
Author(s):  
A. Zatezalo ◽  
A. El-Fallah ◽  
R. Mahler ◽  
R. K. Mehra ◽  
K. Pham
Keyword(s):  
Situational Awareness ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Space Situational Awareness ◽  
Constellation Design ◽  
Sensor Platforms ◽  
Ir Sensor

Multi-objective optimization using parallel simulation for space situational awareness

2018 ◽  
Vol 16 (2) ◽  
pp. 145-157
Author(s):  
Michael S Felten ◽  
John M Colombi ◽  
Richard G Cobb ◽  
David W Meyer
Keyword(s):  
High Performance ◽  
Situational Awareness ◽  
National Policy ◽  
Low Earth Orbit ◽  
Total System ◽  
Space Situational Awareness ◽  
Multi Objective ◽  
Multi Objective Genetic Algorithm ◽  
Space Objects ◽  
Synchronous Orbit

Improving space situational awareness (SSA) remains one of the Department of Defense’s (DoD) top priorities. Current research has shown that the modeling of geosynchronous orbit (GEO) SSA architectures can help identify optimal combinations of ground- and space-based sensors. This paper extends previous research by expanding design boundaries and refining the methodology. A multi-objective genetic algorithm was used to examine this increased trade-space containing 1022 possible design combinations. The results of the optimizer clearly favor 1.0 m aperture ground telescopes combined with 0.15 m aperture sensors in a 12-satellite geosynchronous polar orbit (GPO) constellation. The GPO regime offers increased access to GEO resident space objects (RSO) since other orbits are restricted by a 40° solar exclusion angle. When performance is held constant, a GPO satellite constellation offers a 22.4% reduction in total system cost when compared to Sun synchronous orbit (SSO), equatorial low earth orbit (LEO), and near-GEO constellations. Parallel high-performance computing provides the possibility of solving an entirely new class of complex problems of interest to the DoD. The results of this research can educate national policy makers on the benefits of proposed upgrades to current and future SSA systems.

scholarly journals Optimal Walker Constellation Design of LEO-Based Global Navigation and Augmentation System

2020 ◽  
Vol 12 (11) ◽  
pp. 1845
Author(s):  
Meiqian Guan ◽  
Tianhe Xu ◽  
Fan Gao ◽  
Wenfeng Nie ◽  
Honglei Yang
Keyword(s):  
Genetic Algorithm ◽  
Elevation Angle ◽  
Satellite System ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Constellation Design ◽  
Computation Efficiency ◽  
Leo Satellites ◽  
Global Navigation ◽  
Walker Constellation

Low Earth orbit (LEO) satellites located at altitudes of 500 km~1500 km can carry much stronger signals and move faster than medium Earth orbit (MEO) satellites at about a 20,000 km altitude. Taking advantage of these features, LEO satellites promise to make contributions to navigation and positioning where global navigation satellite system (GNSS) signals are blocked as well as the rapid convergence of precise point positioning (PPP). In this paper, LEO-based optimal global navigation and augmentation constellations are designed by a non-dominated sorting genetic algorithm III (NSGA-III) and genetic algorithm (GA), respectively. Additionally, a LEO augmentation constellation with GNSS satellites included is designed using the NSGA-III. For global navigation constellations, the results demonstrate that the optimal constellations with a near-polar Walker configuration need 264, 240, 210, 210, 200, 190 and 180 satellites with altitudes of 900, 1000, 1100, 1200, 1300, 1400 and 1500 km, respectively. For global augmentation constellations at an altitude of 900 km, for instance, 72, 91, and 108 satellites are required in order to achieve a global average of four, five and six visible satellites for an elevation angle above 7 degrees with one Walker constellation. To achieve a more even coverage, a hybrid constellation with two Walker constellations is also presented. On this basis, the GDOPs (geometric dilution of precision) of the GNSS with and without an LEO constellation are compared. In addition, we prove that the computation efficiency of the constellation design can be considerably improved by using master–slave parallel computing.

scholarly journals Geocentric Spherical Surfaces Emulating the Geostationary Orbit at Any Latitude with Zenith Links

2020 ◽  
Vol 12 (1) ◽  
pp. 16 ◽  
Author(s):  
Emilio Matricciani
Keyword(s):  
Free Space ◽  
Orbital Plane ◽  
Low Earth Orbit ◽  
Service Area ◽  
Geostationary Orbit ◽  
Earth Orbit ◽  
Tropospheric Propagation ◽  
Geostationary Earth Orbit ◽  
Constellation Design ◽  
Spherical Surfaces

According to altitude, the orbits of satellites constellations can be divided into geostationary Earth orbit (GEO), medium Earth orbit (MEO), and low Earth orbit (LEO) constellations. We propose to use a Walker star constellation with polar orbits, at any altitude, to emulate the geostationary orbit with zenith paths at any latitude. Any transmitter/receiver will be linked to a satellite as if the site were at the equator and the satellite at the local zenith. This constellation design can have most of the advantages of the current GEO, MEO, and LEO constellations, without having most of their drawbacks. Doppler phenomena are largely minimized because the connected satellite is always seen almost at the local zenith. The extra free-space loss, due to the fixed pointing of all antennas, is at most 6 dBs when the satellite enters or leaves the service area. The connections among satellites are easy because the positions in the orbital plane and in adjacent planes are constant, although with variable distances. No steering antennas are required. The tropospheric propagation fading and scintillations are minimized. Our aim is to put forth the theoretical ideas about this design, to which we refer to as the geostationary surface (GeoSurf) constellation.

scholarly journals Extended Geometry and Probability Model for GNSS+ Constellation Performance Evaluation

2020 ◽  
Vol 12 (16) ◽  
pp. 2560
Author(s):  
Lingdong Meng ◽  
Jiexian Wang ◽  
Junping Chen ◽  
Bin Wang ◽  
Yize Zhang
Keyword(s):  
Probability Model ◽  
Satellite System ◽  
Low Earth Orbit ◽  
Earth Orbit ◽  
Navigation Satellite ◽  
Constellation Design ◽  
Leo Satellites ◽  
Satellite Visibility ◽  
Global Navigation Satellite ◽  
Gnss Constellation

We proposed an extended geometry and probability model (EGAPM) to analyze the performance of various kinds of (Global Navigation Satellite System) GNSS+ constellation design scenarios in terms of satellite visibility and dilution of precision (DOP) et al. on global and regional scales. Different from conventional methods, requiring real or simulated satellite ephemerides, this new model only uses some basic parameters of one satellite constellation. Verified by the reference values derived from precise satellite ephemerides, the accuracy of visible satellite visibility estimation using EGAPM gets an accuracy better than 0.11 on average. Applying the EGAPM to evaluate the geometry distribution quality of the hybrid GNSS+ constellation, where highly eccentric orbits (HEO), quasi-zenith orbit (QZO), inclined geosynchronous orbit (IGSO), geostationary earth orbit (GEO), medium earth orbit (MEO), and also low earth orbit (LEO) satellites included, we analyze the overall performance quantities of different constellation configurations. Results show that QZO satellites perform slightly better in the Northern Hemisphere than IGSO satellites. HEO satellites can significantly improve constellation geometry distribution quality in the high latitude regions. With 5 HEO satellites included in the third-generation BeiDou navigation satellite system (BDS-3), the average VDOP (vertical DOP) of the 30° N–90° N region can be decreased by 16.65%, meanwhile satellite visibility can be increased by 38.76%. What is more, the inclusion of the polar LEO constellation can significantly improve GNSS service performance. When including with 288 LEO satellites, the overall DOPs (GDOP (geometric DOP), HDOP (horizontal DOP), PDOP (position DOP), TDOP (time DOP), and VDOP) are decreased by about 40%, and the satellite visibility can be increased by 183.99% relative to the Global Positioning System (GPS) constellation.

Design of a Low Earth Orbit Satellite Constellation Network for Air Traffic Surveillance

2020 ◽  
Vol 73 (6) ◽  
pp. 1263-1283
Author(s):  
Jianming Guo ◽  
Lei Yang ◽  
Quan Chen ◽  
Sunquan Yu ◽  
Xiaoqian Chen ◽  
...  
Keyword(s):  
Evaluation Model ◽  
Low Earth Orbit ◽  
Air Traffic ◽  
Earth Orbit ◽  
Traffic Surveillance ◽  
Satellite Constellation ◽  
Constellation Design ◽  
Orbit Satellite ◽  
Satellite Links ◽  
Low Earth Orbit Satellite

The satellite constellation with automatic dependent surveillance-broadcast on-board is of great importance for air traffic surveillance due to its multiple advantages compared with traditional methods. Although some research has been conducted on satellite constellation design based on coverage performance, the findings cannot entirely satisfy all the requirements of air traffic surveillance owing to the lack of analysis on inter-satellite links and network transmission. This paper presents a novel design of a low earth orbit satellite constellation network to solve this problem. Based on the requirements of space-based surveillance, an evaluation model of constellation performance is proposed concerning coverage, link and transmission. The simulation results show that the evaluation model can reflect the performance of a satellite constellation network designed for a space-based surveillance system, and a 55-satellite constellation design scheme with fairly good performance can fulfil the function of global real-time air traffic surveillance.

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