Assessed Cataloguing Performance of a Proposed European Space Surveillance System
- Paper number
IAC-06-B6.1.09
- Author
Mrs. Noelia Sanchez Ortiz, DEIMOS Space, Spain
- Coauthor
Mr. Miguel Bello Mora, DEIMOS Space S.L., Spain
- Coauthor
Mrs. Eva Tresaco, DEIMOS Space S.L., Spain
- Coauthor
Dr. Heiner Klinkrad, European Space Agency/ESOC, Germany
- Year
2006
- Abstract
In the framework of a potential European Space Surveillance System, a study of its capabilities has been done. For such purpose, an end-to-end simulator has been developed, comprising: population environment simulation, measurements generation, orbit determination tasks, correlation and cataloguing activities and delivery of products, among them, collision risk computation, re-entry events reporting, fragmentation analysis and launch detection.
The Space environment simulation allows the generation and propagation of LEO, MEO, HEO, GEO and GTO population and the introduction of some events such as launches, in-orbit break-ups and collisions. Once the space environment is simulated, radar and optical measurements have to be generated. For each body in the space population, visibility determination is accomplished with different filters and discarding criteria, leading to important saving in computation time.
Within all the tasks being done within the system, the correlation and cataloguing process of the simulated space surveillance system is the most demanding one. This task is based on orbit determination by means of radar measurements and the use of a batch Square Root Information Filter (SRIF). During the operations of a future space surveillance system, every radar track received at the control centre should be processed to update the information of the associated object (if it has been previously catalogued) or to introduce a new object in the catalogue. If the object was not previously tracked; then a first rough estimation of the position has to be calculated. A reduced number of measurements are introduced into an Initial Orbit Determination algorithm. Semi analytical methods such as Baker R-iteration and Modified Laplacian algorithms and some slight modifications of them (Gibbs method, Smoothing sigma errors, Statistics technique,...) have been implemented providing a poorly accurate initial state vector. With the aim of obtaining higher accuracy level, a new initial orbit determination algorithm has been defined and implemented. This new algorithm is based on a combination of Line of Sight information and Lambert solution suitable for radar measurements.
Different procedures to correlate a new tracked object with previously detected ones have been studied, however they all have as main drawback large computation workloads. A procedure based on comparison of actual and predicted tracks to come, with minimum measurement residual computation, was selected due to its lower computation time. It follows a chronological processing of the tracks. For every new/updated object in catalogue, expected following tracks are pre-computed. These expected tracks are compared with actual tracks of real measurements; a track time filter selects the candidate objects and that with minimum measurements residuals is selected as object to be updated. If there are no candidates, the first orbit determination is computed and a new object is introduce in the catalogue.
Preliminary results for the capabilities of a European Space Surveillance System show good performances for the cataloguing operations. A correlation error below 5% of tracks may be achievable. Up to 90% of the population can be catalogued with an uncertainty below 10 m and 10 mm/s for position and velocity of orbiting objects in LEO. The accurate orbit determination leads to extremely useful post-processing data. Collision Risk analyses provide forecast of miss-encounter with enough anticipation and low level of false alarm rate. Accurate reporting of re-entry objects and fragmentation detection are also available.
The simulation of the features of a possible European Space Surveillance System has been done by means of the Advanced Space Surveillance System simulator (AS4) developed by DEIMOS space, under ESA contract.
- Abstract document
- Manuscript document
IAC-06-B6.1.09.pdf (🔒 authorized access only).
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