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Papers by Surendra Ray

Research paper thumbnail of Analytical Study of Hilbert Space and Algebra of Operators

This present paper deals with the study of Hilbert Space and Algebra of Operators. Here, we consi... more This present paper deals with the study of Hilbert Space and Algebra of Operators. Here, we consider R as additive group of reals with discrete topology and several ways of constructing C* algebras Canonically associated with R and π, The Universal representation of R on Hilbert Space H, it is proved in this paper that all C*algebras homomorphism and representation will be * preserving

Research paper thumbnail of Attitude determination using an adaptive multiple model filtering Scheme

Flight Mechanics Estimation Theory Symposium 1995, May 1, 1995

Attitude determination has been considered as a permanent topic of active research and perhaps re... more Attitude determination has been considered as a permanent topic of active research and perhaps remaining as a forever-lasting interest for spacecraft system designers. Its role is to provide a reference for controls such as pointing the directional antennas or solar panels, stabilizing the spacecraft or maneuvering the spacecraft to a new orbit. Least Square Estimation (LSE) technique was utilized to provide attitude determination for the Nimbus 6 and G. Despite its poor performance (estimation accuracy consideration), LSE was considered as an effective and practical approach to meet the urgent need and requirement back in the 70's. One reason for this poor performance associated with the LSE scheme is the lack of dynamic filtering or 'compensation'. In other words, the scheme is based totally on the measurements and no attempts were made to model the dynamic equations of motion of the spacecraft. We propose an adaptive filtering approach which employs a bank of Kalman filters to perform robust attitude estimation. The proposed approach, whose architecture is depicted, is essentially based on the latest proof on the interactive multiple model design framework to handle the unknown of the system noise characteristics or statistics. The concept fundamentally employs a bank of Kalman filter or submodel, instead of using fixed values for the system noise statistics for each submodel (per operating condition) as the traditional multiple model approach does, we use an on-line dynamic system noise identifier to 'identify' the system noise level (statistics) and update the filter noise statistics using 'live' information from the sensor model. The advanced noise identifier, whose architecture is also shown, is implemented using an advanced system identifier. To insure the robust performance for the proposed advanced system identifier, it is also further reinforced by a learning system which is implemented (in the outer loop) using neural networks to identify other unknown quantities such as spacecraft dynamics parameters, gyro biases, dynamic disturbances, or environment variations.

Research paper thumbnail of INVITED ARTICLE: The physics of space research

Research paper thumbnail of Study of Properties of Transition Metal Atoms and Ions by Many-Body Perturbation Theory

Research paper thumbnail of Analytical Study of Hilbert Space and Algebra of Operators

This present paper deals with the study of Hilbert Space and Algebra of Operators. Here, we consi... more This present paper deals with the study of Hilbert Space and Algebra of Operators. Here, we consider R as additive group of reals with discrete topology and several ways of constructing C* algebras Canonically associated with R and π, The Universal representation of R on Hilbert Space H, it is proved in this paper that all C*algebras homomorphism and representation will be * preserving

Research paper thumbnail of Attitude determination using an adaptive multiple model filtering Scheme

Flight Mechanics Estimation Theory Symposium 1995, May 1, 1995

Attitude determination has been considered as a permanent topic of active research and perhaps re... more Attitude determination has been considered as a permanent topic of active research and perhaps remaining as a forever-lasting interest for spacecraft system designers. Its role is to provide a reference for controls such as pointing the directional antennas or solar panels, stabilizing the spacecraft or maneuvering the spacecraft to a new orbit. Least Square Estimation (LSE) technique was utilized to provide attitude determination for the Nimbus 6 and G. Despite its poor performance (estimation accuracy consideration), LSE was considered as an effective and practical approach to meet the urgent need and requirement back in the 70's. One reason for this poor performance associated with the LSE scheme is the lack of dynamic filtering or 'compensation'. In other words, the scheme is based totally on the measurements and no attempts were made to model the dynamic equations of motion of the spacecraft. We propose an adaptive filtering approach which employs a bank of Kalman filters to perform robust attitude estimation. The proposed approach, whose architecture is depicted, is essentially based on the latest proof on the interactive multiple model design framework to handle the unknown of the system noise characteristics or statistics. The concept fundamentally employs a bank of Kalman filter or submodel, instead of using fixed values for the system noise statistics for each submodel (per operating condition) as the traditional multiple model approach does, we use an on-line dynamic system noise identifier to 'identify' the system noise level (statistics) and update the filter noise statistics using 'live' information from the sensor model. The advanced noise identifier, whose architecture is also shown, is implemented using an advanced system identifier. To insure the robust performance for the proposed advanced system identifier, it is also further reinforced by a learning system which is implemented (in the outer loop) using neural networks to identify other unknown quantities such as spacecraft dynamics parameters, gyro biases, dynamic disturbances, or environment variations.

Research paper thumbnail of INVITED ARTICLE: The physics of space research

Research paper thumbnail of Study of Properties of Transition Metal Atoms and Ions by Many-Body Perturbation Theory

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