Hi Some other work on the Commensal use of Radio Telescope assets for space junk monitoring.
https://open.uct.ac.za/handle/11427/26890 System design of the MeerKAT L - band 3D radar for monitoring near earth objects http://hdl.handle.net/11427/26890 Theses / Dissertations > PhD / Doctoral Abstract: This thesis investigates the current knowledge of small space debris (diameter less than 10 cm) and potentially hazardous asteroids (PHA) by the use of radar systems. It clearly identifies the challenges involved in detecting and tracking of small space debris and PHAs. The most significant challenges include: difficulty in tracking small space debris due to orbital instability and reduced radar cross-section (RCS), errors in some existing data sets, the lack of dedicated or contributing instruments in the Southern Hemisphere, and the large cost involved in building a high-performance radar for this purpose. This thesis investigates the cooperative use of the KAT-7 (7 antennas) and MeerKAT (64 antennas) radio telescope receivers in a radar system to improve monitoring of small debris and PHAs was investigated using theory and simulations, as a cost-effective solution. Parameters for a low cost and high-performance radar were chosen, based on the receiver digital back-end. Data from such radars will be used to add to existing catalogues thereby creating a constantly updated database of near Earth objects and bridging the data gap that is currently being filled by mathematical models. Based on literature and system requirements, quasi-monostatic, bistatic, multistatic, single input multiple output (SIMO) radar configurations were proposed for radio telescope arrays in detecting, tracking and imaging small space debris in the low Earth orbit (LEO) and PHAs. The maximum dwell time possible for the radar geometry was found to be 30 seconds, with coherent integration limitations of 2 ms and 121 ms for accelerating and non-accelerating targets, respectively. The multistatic and SIMO radar configurations showed sufficient detection (SNR 13 dB) for small debris and quasi-monostatic configuration for PHAs. Radar detection, tracking and imaging (ISAR) simulations were compared to theory and ambiguities in range and Doppler were compensated for. The main contribution made by this work is a system design for a high performance, cost effective 3D radar that uses the KAT-7 and MeerKAT radio telescope receivers in a commensal manner. Comparing theory and simulations, the SNR improvement, dwell time increase, tracking and imaging capabilities, for small debris and PHAs compared to existing assets, was illustrated. Since the MeerKAT radio telescope is a precursor for the SKA Africa, extrapolating the capabilities of the MeerKAT radar to the SKA radar implies that it would be the most sensitive and high performing contributor to space situational awareness, upon its completion. From this feasibility study, the MeerKAT 3D distributed radar will be able to detect debris of diameter less than 10 cm at altitudes between 700 km to 900 km, and PHAs, with a range resolution of 15 m, a minimum SNR of 14 dB for 152 pulses for a coherent integration time of 2.02 ms. The target range (derived from the two way delay), velocity (from Doppler frequency) and direction will be measured within an accuracy of: 2.116 m, 15.519 m/s, 0.083° (single antenna), respectively. The range, velocity accuracies and SNR affect orbit prediction accuracy by 0.021 minutes for orbit period and 0.0057° for orbit inclination. The multistatic radar was found to be the most suitable and computationally efficient configuration compared to the bistatic and SIMO configurations, and beamforming should be implemented as required by specific target geometry. Reference: Agaba, D. 2017. System design of the MeerKAT L - band 3D radar for monitoring near earth objects. University of Cape Town. https://open.uct.ac.za/handle/11427/29617 Mission Planning Tool for space debris studies with the MeerKAT radar http://hdl.handle.net/11427/29617 Theses / Dissertations > Masters Abstract: The Radar Remote Sensing Group at the University of Cape Town is currently investigating the feasibility of building an active radar system employing the MeerKAT radio telescope as receiver for space debris detection, tracking and imaging. This dissertation details the development of a Mission Planning Tool (MPT) to perform sensor scheduling and to support the performance prediction and analysis of the proposed MeerKAT radar. The MeerKAT radar project proposal is made in the context of developing space surveillance and tracking capacities in South Africa. The MeerKAT radar is intended to operate bistatically, with a transmitter located in Bredasdorp (South Africa) and the MeerKAT radio telescope as receiver. The system design and radar signal processing design are currently under development in another RRSG project. Before the feasibility study can progress further, a Mission Planning Tool has been developed to assist in scheduling the bistatic radar to perform an observation experiment, to calculate the predicted radar measurements and errors as well as to estimate the orbit of the observed object. This report documents how these objectives were met by the MPT software developed in Python. Given a LEO space object of interest’s Two Line Element set, the MPT performs orbit propagation with an SGP4 method to generate trajectories for radar performance evaluation. The MPT determines the most opportune epoch (the longest possible target dwell-time within the antenna beam) for executing an observation experiment with the MeerKAT radar. Space objects investigated in this project were found to be have spent between 4.5 s to 12.8 s in the transmitter’s illuminating beam. The MeerKAT radio telescopes are tasked to act as receivers at the appropriate antenna pointing and time period. Based on the bistatic geometry of the specific observation experiment, the MPT predicts the signal-to-noise ratio at the radar receiver as well as the bistatic range, bistatic Doppler shift and look angles. The integrated SNR values for the experiments considered in this report ranged from 11 dB to 68 dB. From the coherently integrated SNR, the MPT estimates the radar measurement errors. Finally, the orbit determination module was engineered with two radar measurement schemes: a bistatic range and Doppler shift scheme and a bistatic range and look angles scheme. Monte Carlo experiments were run to evaluate the tracking performance resulting from the two tracking schemes. The Gauss-Newton tracking filter based on the first scheme fails to converge whereas it produces accurate results with the second scheme (estimated position error of 2 m and velocity error of 0.08 m/s). It is therefore recommended to opt for the bistatic range and look angles measurement scheme in future work. Since the current MeerKAT radar design cannot create look angles measurements, an observables estimation scheme was adopted. It was found that this scheme produced accurate elevation and azimuth angles with an estimation error of ±0.04◦ . Since the quoted values result from a preliminary design of the MeerKAT radar, they are bound to change in the final design. Therefore the MPT should be loaded with the final radar design’s parameters and run again to produce useful results. This reports shows that, with the help of the Mission Planning Tool developed in this project, the proposed MeerKAT radar can be feasibly scheduled to observe and track space objects in the LEO regime based on a single target pass. Reference: Dhondea, A. 2018. Mission Planning Tool for space debris studies with the MeerKAT radar. University of Cape Town. On Tue, 3 Sep 2019 at 10:17, Adam Isaacson <[email protected]> wrote: > > Dear Casperites, > > The Red Pitaya hardware is primarily an educational platform for Casperites, > but it can have real world applications - in this case the Sardinia Radio > Telescope acts as a receiver for a bistatic radar system, which detects space > debris. This article has been sent by Andrea Melis and Raimondo Concu from > INAF and have given me the go ahead to publish this paper to the broader > community. Please note that these Red Pitayas are not currently using the > CASPER toolflow. > > From Andrea Melis: "Sure, you can share this work, I have attached the > recently accepted (July 1st) paper that will be shortly published in the IEEE > Antennas and Propagation Magazine; fig. 15 and 16 shows spectra and > spectrograms that we captured with Red Pitayas during two passages of the > Tiangong-1. With regard to the firmware, we slightly modified the wideband > SDR transceiver available at following link (number 10 of the list): > http://pavel-demin.github.io/red-pitaya-notes/"; > > Many thanks to Andrea and Raimondo for sharing this with us! Great work, guys! > > Kind regards, > > Adam Isaacson > South African Radio Astronomy Observatory (SARAO) > Hardware Manager > Cell: (+27) 825639602 > Tel: (+27) 215067300 > email: [email protected] > > -- > You received this message because you are subscribed to the Google Groups > "[email protected]" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CADTJ%3DnHtfTsMr%3DVxVMeUnWB5S1aGC0OYP1BBhMGLOa_PNbJryA%40mail.gmail.com. -- Michael Inggs 10 Devon Street, Simon's Town, South Africa. Tel: +27 21 786 1723 Fax: +27 21 786 1151 Skype: mikings Cell: +27 83 776 7304 "Ex Africa semper aliquid novi" -- You received this message because you are subscribed to the Google Groups "[email protected]" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/CADhK9PEj1tyP4hYzsv2JpbRtyHXKF899a1DKiwyd%3DkYyMDGxQw%40mail.gmail.com.
