Creat membership Creat membership
Sign in

Forgot password?

Confirm
  • Forgot password?
    Sign Up
  • Confirm
    Sign In
home > search

Now showing items 1 - 16 of 32

  • Rotations, Transformations, Left Quaternions, Right Quaternions?

    Zanetti, Renato  

    Download Collect
  • Adaptive Kalman Filter for Detectable Linear Time-Invariant Systems

    Moghe, Rahul   Zanetti, Renato   Akella, Maruthi R.  

    A novel covariance matching technique is proposed for estimating the states and unknown entries of the process and measurement noise covariance matrices for additive white Gaussian noise elements in a linear Kalman filter. Under this assumption of detectability (that is, unobservable modes remain stable), the stability and convergence properties of the covariance matching Kalman filter are established. It is shown that the measurement covariance matrix cannot be unambiguously estimated if the measurement model contains linearly dependent measurements. Monte Carlo simulations evaluate the numerical properties of the proposed algorithm.
    Download Collect
  • Rotations, Transformations, Left Quaternions, Right Quaternions?

    Zanetti, Renato  

    Download Collect
  • Sequential Monte Carlo Filtering with Gaussian Mixture Sampling

    Yun, Sehyun   Zanetti, Renato  

    Download Collect
  • Fully Multiplicative Unscented Kalman Filter for Attitude Estimation

    Zanetti, Renato   DeMars, Kyle J.  

    Download Collect
  • Automated Splitting Gaussian Mixture Nonlinear Measurement Update

    Tuggle, Kirsten   Zanetti, Renato  

    Download Collect
  • Fully Multiplicative Unscented Kalman Filter for Attitude Estimation

    Zanetti, Renato   DeMars, Kyle J.  

    Download Collect
  • Design and Flight Performance of the Orion Prelaunch Navigation System

    Zanetti, Renato   Holt, Greg   Gay, Robert   D'Souza, Christopher   Sud, Jastesh   Mamich, Harvey   Gillis, Robert  

    The design of National Aeronautics and Space Administration Orion's prelaunch navigation system is introduced, both for the first flight test, Exploration Flight Test 1, and for the first planned Orion mission, Exploration Mission 1. A detailed tradeoff of possible design decisions is discussed, and the choices made by Orion are presented. The actual performance of the navigation system during Exploration Flight Test 1 is presented together with the navigation flight-software data provided by Orion to the ground controllers in telemetry.
    Download Collect
  • Design and Flight Performance of the Orion Prelaunch Navigation System

    Zanetti, Renato   Holt, Greg   Gay, Robert   D’Souza, Christopher   Sud, Jastesh   Mamich, Harvey   Gillis, Robert  

    Download Collect
  • Absolute Navigation Performance of the Orion Exploration Flight Test 1

    Zanetti, Renato   Holt, Greg   Gay, Robert   D’Souza, Christopher   Sud, Jastesh   Mamich, Harvey   Begley, Michael   King, Ellis   Clark, Fred D.  

    Download Collect
  • Absolute Navigation Performance of the Orion Exploration Flight Test 1

    Zanetti, Renato   Holt, Greg   Gay, Robert   D'Souza, Christopher   King, Ellis   Clark, Fred D.  

    Launched in December 2014 atop a Delta IV Heavy from the Kennedy Space Center, the Orion vehicle's Exploration Flight Test 1 successfully completed the objective to stress the system by placing the uncrewed vehicle on a high-energy parabolic trajectory, replicating conditions similar to those that would be experienced when returning from an asteroid or a lunar mission. Unique challenges associated with designing the navigation system for Exploration Flight Test 1 are presented with an emphasis on how redundancy and robustness influenced the architecture. Two inertial measurement units, one GPS receiver, and three barometric altimeters comprise the navigation sensor suite. The sensor data are multiplexed, using conventional integration techniques, and the state estimate is refined by the GPS pseudo- and delta-range measurements in an extended Kalman filter that employs UDU factorization. The performance of the navigation system during flight is presented to substantiate the design.
    Download Collect
  • Dealing with uncertainties in angles-only initial orbit determination

    Armellin, Roberto   Di Lizia, Pierluigi   Zanetti, Renato  

    A method to deal with uncertainties in initial orbit determination (IOD) is presented. This is based on the use of Taylor differential algebra (DA) to nonlinearly map uncertainties from the observation space to the state space. When a minimum set of observations is available, DA is used to expand the solution of the IOD problem in Taylor series with respect to measurement errors. When more observations are available, high order inversion tools are exploited to obtain full state pseudo-observations at a common epoch. The mean and covariance of these pseudo-observations are nonlinearly computed by evaluating the expectation of high order Taylor polynomials. Finally, a linear scheme is employed to update the current knowledge of the orbit. Angles-only observations are considered and simplified Keplerian dynamics adopted to ease the explanation. Three test cases of orbit determination of artificial satellites in different orbital regimes are presented to discuss the feature and performances of the proposed methodology.
    Download Collect
  • Bezier Description of Space Trajectories

    de Dilectis, Francesco   Mortari, Daniele   Zanetti, Renato  

    Download Collect
  • Adaptable Recursive Update Filter

    Zanetti, Renato  

    Download Collect
  • Recursive Implementations of the Schmidt-Kalman ‘Consider’ Filter

    Zanetti, Renato   D’Souza, Christopher  

    One method to account for parameters errors in the Kalman filter is to ‘consider’ their effect in the so-called Schmidt-Kalman filter. This paper addresses issues that arise when implementing a consider Kalman filter as a real-time, recursive algorithm. A favorite implementation of the Kalman filter as an onboard navigation subsystem is the UDU formulation. A new way to implement a UDU Schmidt-Kalman filter is proposed. The non-optimality of the recursive Schmidt-Kalman filter is also analyzed, and a modified algorithm is proposed to overcome this limitation.
    Download Collect
  • Observability Analysis and Filter Design for the Orion Earth-Moon Attitude Filter

    Zanetti, Renato   D'Souza, Christopher N.  

    The Orion attitude navigation design is presented, together with justification of the choice of states in the filter and an analysis of the observability of its states while processing star tracker measurements. The analysis shows that when the gyroscope biases and scale factors drift at different rates and are modeled as first-order Gauss-Markov processes, the states are observable so long as the time constants are not the same for both sets of states. In addition, the inertial-measurement-unit-to-star-tracker misalignments are modeled as first-order Gauss-Markov processes and these states are estimated. These results are used to finalize the design of the attitude estimation algorithm and the attitude calibration maneuvers.
    Download Collect
1 2

Contact

If you have any feedback, Please follow the official account to submit feedback.

Turn on your phone and scan

Submit Feedback