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International Review of Aerospace Engineering - December 2011 (Vol. 4 N. 6) - Papers

	Model Uncertainty Approach to Aircraft Angular Rate Estimation using Kalman-Bucy Filtering Designing a GaAs Photonic Crystals Narrow Band Filter Roadmap for Electromagnetic Compatibility Qualification of Payloads for Space Commercialization CDMA Slotted ALOHA in Satellite Communication Weight Optimization of a Solid Propellant Rocket Engine Based in Fuel Formulation

International Review of Aerospace Engineering - Papers

Model Uncertainty Approach to Aircraft Angular Rate Estimation using Kalman-Bucy Filtering
by K. Bousson, Nuno F. L. Maia, António S. Lebres

Vol. 4. n. 6, pp. 307-314

Abstract - Angular rate estimation for gyroless aerospace vehicles has shown a great interest for the sake of mission weight minimization. Besides, even for gyro-equipped vehicles, angular rate estimation is still necessary as it provides means for additional measurements that may be used for accurate attitude estimation through multi-sensor data fusion procedures. Based on the Kalman-Bucy filtering approach, the present paper proposes an angular rate estimation method that uses only the velocity measurements and flight dynamics equations; therefore, it solves the problem of estimating aircraft gyroscopic measurements from accelerometric ones. The key idea that is put forth in the proposed method is the estimation of the system model errors. Two case studies are presented that demonstrate the accuracy of the method in estimating successfully the angular rates of a gyroless unmanned aerial vehicle.

Keywords: Kalman-Bucy Filter, Model Uncertainties, Gyroless Estimation of Angular Rates.

Designing a GaAs Photonic Crystals Narrow Band Filter
by A. Boudissa, M. Benslama

Vol. 4. n. 6, pp. 315-318

Abstract - In this research, we propose a new type of photonic crystal narrow band filter. It is based the coupling between the line defect and point defect in tow-dimensional crystal (2D-PhC). The simulation method used in the present study is the plan expansion method and finite difference time domain methods. Obtained results show that the filter has good capacity to transmit light in an indicated band.

Keywords: Photonic Crystal, FDTD, Coupled Cavity-Wave Guide, Optical Filter, Narrow Band Filter.

Roadmap for Electromagnetic Compatibility Qualification of Payloads for Space Commercialization
by Bartel van der Veek, Hector M. Gutierrez, Daniel R. Kirk, Fredric M. Ham

Vol. 4. n. 6, pp. 319-327

Abstract - A major challenge that new space commercialization companies are facing is the qualification of their space-based payloads for electromagnetic compatibility during launch operations. Electromagnetic compatibility (EMC) qualification is typically a lengthy and expensive procedure from the point of view of alternative launch providers, who typically lack the dedicated expertise as well as historical and often proprietary databases of legacy vehicles. When a payload is completed, it is usually submitted for EMC qualification to a testing laboratory that provides a report stating whether or not the payload complies with required standards. A negative result typically provides little insight to the alternate launch provide in terms of what corrective measures and design modifications are required to make the payload pass the EMC tests on a subsequent iteration. For this reason, it is of great value to a customer to have better insight into the EMC qualification procedure. The roadmap for EMC qualification presented in this study is intended to help guide an alternative launch provider through the payload design and qualification process. Furthermore, the roadmap presented here will show options for performing preliminary tests and how to iterate the payload design to increase the likelihood of successful EMC compliance testing.
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Keywords: Space Commercialization, Electromagnetic Compatibility, Payload Qualification.

CDMA Slotted ALOHA in Satellite Communication
by M. Belattar, D. Benatia, M. Benslama

Vol. 4. n. 6, pp. 328-332

Abstract - In this paper the case of finite users in Slotted Aloha System is studied, the scheme of two channels, uplink and downlink in satellite communication in presented, the error probability, signal to signal plus interference ratio and the probability of a successful transmission using the CDMA Model are also presented.

Keywords: CDMA Model, Slotted ALOHA, Signal To Noise Ratio, and Bit Error Probability.

Weight Optimization of a Solid Propellant Rocket Engine Based in Fuel Formulation
by Francisco J. F. Carande, Francisco M. Brójo

Vol. 4. n. 6, pp. 333-338

Abstract - The total weight of a rocket has an important influence on its performance, i.e., when the weight decreases, the performance is improved. This work is carried out to optimize the weight of the sustainer of a sounding rocket based on the formulation of the solid propellant motor. Influential factors were calculated in the performance of the set and verified the most influential ones.

Keywords: Performance, Sounding Rocket, Solid Propellant.