Abstract
Although direct measurements of the projected areas of various Geosynchronous Earth Orbit (GEO) satellite facets are impossible without high-resolution imaging, estimates of the albedo-Area (aA) product lead to the possibility of inferring the geometric size of an RSO based on the illuminated area. Such size estimates are an integral part of its identity because satellite mission capabilities can be inferred. We are engaged in parallel development of two methods for calculating aA for the body/communication antennas structures and one method for the solar panels. We have previously reported on the Two Facet Model (2FM) method for body aA, and here we discuss a method based on differences between new observations and a baseline catalog that has been constructed from the GEO Observations with Longitudinal Diversity Simultaneously (GOLDS) data. We report on evaluations of the 2FM and Differential Method (DM) algorithm results. We also discuss a new method of estimating solar panel aA by fitting new data that include specular glints. All of these measurement methods are compared to models and simulations that serve as a proxy for ground truth. Because of the partially directional nature of the composite Bi-directional Reflectivity Distribution Function (BRDF) of all bus-mounted appendages, variance of body aA results is expected to be significant. Short-term and long-term variance of the derived aAs will also be discussed.
Highlights
We have been conducting both observational and analysis programs for geostationary satellites
For those objects with more complex signatures (i.e., those with broad shoulders or secondary peaks that are located in the general range of 20o < abs(LPA) < 40o), we find that the two methods disagree and that the 2FM method computes consistently larger body aAs than the Differential Method (DM) method does
The DM method excludes brightness data that lies in the range abs(LPA) < 40o, whereas the 2FM method often includes brightness data that lies in the range 20o < abs(LPA) < 40o
Summary
We have been conducting both observational and analysis programs for geostationary satellites. The research presented here is aimed at deriving effective estimates of the sizes of these objects by calculating the albedo-Area (aA) products of the bus/payload/com antennas and solar panels based on “new data,” using the GCPC and GOLDS catalogs to develop our algorithms. The method we use is as follows: We only use the lambertian observations with γ(orbit angle) values in [−75, 75] to calculate the body diffuse aA.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
