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Seymour M.A.,Groupon | Moffat B.,Com Dev Inc. | Mason S.,Com Dev Inc. | Sylvestre B.,Neptec | And 2 more authors.
Proceedings of the International Astronautical Congress, IAC | Year: 2016

The growing issue of space debris in near-Earth orbit is gaining increasing attention and urgency within the international space community. There is a real danger of a "cascading effect" or tipping point being reached, where debris generation rates become self-sustaining and accelerate population growth. The existing debris population is of primary concern, particularly the larger (¿1000 kg mass) objects which, on a per-object basis, present the most significant risk of adding to the total mass and number of debris objects if they collide with other bodies and fragment. In mid-2011, the Canadian Space Agency (CSA) commissioned a study into Active Debris Removal (ADR) missions, under its Exploration Core (ExCore) Studies program, to "define the science and technology developments most likely to be required in future space exploration missions of interest to Canada, and assess potential contributions that Canada could make to such missions." Reference debris object targets included spent rocket upper stages, and large, derelict spacecraft. Our ADR solution is called Project MODEL - the Mission for Orbital Debris ELimination. Project MODEL showcases the application of flight-proven or in-development Canadian technologies, which can be readily applied to an ADR mission with stated goals of being able to remove 2-3 large debris objects from Low Earth Orbit per year, over a mission lifetime of 10 years. Such a mission poses great challenges in several key technical areas, including debris object identification and rendezvous, debris object characterization, then grappling and stabilizing a non-cooperative (not designed to be captured) tumbling debris object, and finally lowering and releasing the debris object in a disposal orbit. COM DEV of Cambridge, Ontario performed the lead system engineering role on the study, with NGC Aerospace of Sherbrooke, Québec providing expertise in orbital rendezvous strategies, Neptec of Kanata, Ontario proposing its flight-proven TriDAR laser-vision system for 3-dimensional debris object spot-cloud imaging and characterization, and ESI Robotics of Toronto, Ontario designing a robotic grappling arm for capture and stabilization operations. The study results were returned to the CSA in 2012, providing a viable mission profile, spacecraft and equipment design using technologies currently available and/or under development in Canada, which can rendezvous with, characterize, grapple, control and de-orbit target debris. We are pleased to present the results of this study to a large and international audience, to demonstrate Canada's ability and readiness to contribute technologies and expertise to future ADR missions which aim to tackle this urgent issue. Copyright © 2016 by the International Astronautical Federation (IAF). All rights reserved.


Kudsia C.,University of Waterloo | Keyes L.,RCA | Stajcer A.,Com Dev Inc. | Douville R.,CRC | Nakhla M.,Carleton University
IEEE Microwave Magazine | Year: 2012

Canada was strategically placed at the end of World War II (WWII). There was a significant core of engineering design expertise, not only in the traditional resource and power industries, but also in the rapidly advancing electronics area, particularly the telecommunications sector. This capability was significantly improved with the arrival of many well-trained engineers and technologists from abroad who were escaping repressive regimes or simply looking for opportunity in the new world. We follow the development of microwave components and systems in Canada from an engineering perspective, highlighting the key programs, evolution of key technologies and research activities in the field of microwave theory and practice. © 2012 IEEE.


Lambert C.,Canadian Space Agency | Kumar B.S.,Com Dev Inc. | Hamel J.-F.,NGC Aerospace Ltd | Ng A.,Canadian Space Agency
Acta Astronautica | Year: 2012

Formation flying using only differential drag forces is possible in low Earth orbit. The effectiveness of this technique is addressed for a practical satellite mission. Formation control algorithms typically rely on knowledge of the mean relative position between spacecrafts but this information is not readily available from sensor data and must be approximated using instantaneous sensor data for position and velocity. Several different approaches of obtaining the mean relative position are presented and compared. Two independent controllers are required to achieve precise formation control, one for secular formation maneuvers and another for periodic motion. The performance of each controller is examined using different methods for obtaining estimates of mean relative positions. © 2011 Elsevier Ltd.


Ismail M.,University of Waterloo | Zhuang W.,University of Waterloo | Yu M.,Com Dev Inc.
IEEE Vehicular Technology Conference | Year: 2012

In this paper, radio resource allocation for mobile terminals (MTs) in a heterogeneous wireless access medium is investigated. Unlike the existing solutions in literature, two types of services are considered in this paper, namely single-network and multi-homing services. In single-network services, an MT is assigned to the best available wireless network, while in multi-homing services an MT utilizes all available wireless access networks simultaneously. With the presence of both services in the heterogeneous wireless access medium, the radio resource allocation objective is of twofold: We aim to find the optimal assignment of MTs with single-network service to the available wireless access networks and to determine the corresponding optimal bandwidth allocation to the MTs with single-network and multi-homing services. The radio resource allocation problem is formulated to guarantee the service quality for both service types. Numerical results are presented to demonstrate the performance of the proposed radio resource allocation scheme. © 2012 IEEE.


Shah S.F.A.,Com Dev Inc. | Srirangarajan S.,Nanyang Technological University | Tewfik A.,University of Minnesota
IEEE Transactions on Wireless Communications | Year: 2010

We present the implementation of a directional beacon-based positioning algorithm using radio frequency signals. This algorithm allows each mobile node to compute its position with respect to a set of reference nodes which are equipped with a rotating directional antenna. The use of directional beacon-based algorithm for position location eliminates the need for strict synchronization between the reference nodes and the mobile node. In contrast to positioning algorithms that rely on signal propagation time and bandwidth, the proposed algorithm depends on the beam-width and rotational speed of the directional antenna. We will show that these parameters can be optimized with a low cost solution that provides good positioning accuracy. The system implementation is based on the GNU Radio software platform and the Universal Software Radio Peripheral as the hardware component. We present an enhanced maximum likelihood method for estimating the received signal amplitude profile. To deal with obstructed line-of-sight scenarios, we do not rely purely on the received signal strength and instead formulate a least squares problem to estimate the line-of-sight component in a multipath environment. These advanced signal processing techniques yield a more accurate estimate of the bearing of the mobile node with respect to each of the reference nodes. We also show that the proposed positioning algorithm is tolerant to errors in timing and synchronization. We demonstrate the ability to obtain mobile node position estimates with sub-meter accuracy by transmitting a narrowband signal of 1 kHz bandwidth in the 2.4-2.5 GHz band. The experimental results show a mean position error of 0.759 m, in a field measuring 55m by 43m, using eight 90° rotations of the antenna. © 2006 IEEE.


Yassini B.,Com Dev Inc. | Yu M.,Com Dev Inc. | Keats B.,Com Dev Inc.
IEEE MTT-S International Microwave Symposium Digest | Year: 2012

A TE011 Ka band tunable filter with a stable and continuous tuning performance is presented in this paper. A novel mode-splitter resonator and coupling configuration enabling cross-coupled planar TE011 filter realization is introduced in this work. The concept can be applied to back-to-back coupled TE011 resonator as well. The idea presented in this paper is verified through fabrication of a three-pole Ka-band tunable filter that demonstrates 500 MHz of tuning range with a stable RF tuning performance. © 2012 IEEE.


Yassini B.,Com Dev Inc. | Yu M.,Com Dev Inc.
IEEE MTT-S International Microwave Symposium Digest | Year: 2014

A novel Ka band filter with extremely high quality factor is realized using 22nd and 23rd modes of circular waveguide. A dual mode structure with good spurious performance is presented first time in literature. A cross coupled filter with side launched is demonstrated in this work. The results are supported by measured performance at ambient and over temperature. © 2014 IEEE.


Panariello A.,Com Dev Inc. | Yu M.,Com Dev Inc. | Ernest C.,European Space Agency
IEEE MTT-S International Microwave Symposium Digest | Year: 2012

In this paper, a novel dielectric-resonator filter configuration is presented. The new filter offers superior Q and wider spurious-mode free range at Ku-Band. Moreover it offers 70% mass savings over the TE 114 dual mode design and over 50% foot print reduction compared with the TE 113 dual-mode implementation. These characteristics make this novel technology extremely suitable for output multiplexer used in Ku-Band satellite application. © 2012 IEEE.


Podilchak S.K.,Royal Military College of Canada | Caillet M.,Royal Military College of Canada | Lee D.,Royal Military College of Canada | Antar Y.M.M.,Royal Military College of Canada | And 5 more authors.
IEEE Transactions on Antennas and Propagation | Year: 2013

The development and optimization of a circularly polarized (CP) antenna using an array of four folded-shorted patch elements is investigated. The realized antenna is compact (0.2λ0 by 0.2λ0) , highly integrated, and offers good radiation performance at 400 MHz. A compact coupler-based feeding network for the four elements within the array, integrated into the antenna ground plane, provides a sequential 90° phase difference between the radiating folded-shorted patches. This very compact CP antenna design may be useful for microsatellite and other miniaturized phased array systems for communications. © 1963-2012 IEEE.


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