A robust trajectory optimization approach for rendezvous and proximity operations in perturbed elliptical orbits with uncertainties is proposed. For robust trajectory design, a new discrete-time linear dynamics model ...
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A robust trajectory optimization approach for rendezvous and proximity operations in perturbed elliptical orbits with uncertainties is proposed. For robust trajectory design, a new discrete-time linear dynamics model describing the relative equations of motion for powered flight in perturbed elliptical orbits is developed. The linear dynamics model is used to formulate a stochastic trajectory optimization problem that takes into account navigation sensor errors, maneuver execution errors, and trajectory and control dispersion. The objective of the stochastic optimization problem is to minimize the sum of the expected maneuver and the maneuver dispersion subject to a 3-sigma constraint on the final state dispersion. A genetic algorithm is used to solve the stochastic trajectory optimization problem, and a series of examples demonstrate that the stochastic maneuver solution can be significantly better than the solution corresponding deterministic trajectory optimization problem. Nonlinear Monte Carlo simulations are used to validate the results.
This research considers the technological components required,in an aircraft to safely perform simultaneous, instrument approaches into an airport with parallel runways spaced less than 2500 ft apart. Monte Carlo simu...
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This research considers the technological components required,in an aircraft to safely perform simultaneous, instrument approaches into an airport with parallel runways spaced less than 2500 ft apart. Monte Carlo simulations were used in order to assess the probability of collision during an unexpected aircraft blunder, but many of the input parameters such as flight technical error, navigation sensor error, and pilot time delay were based on recently generated experimental data. This analysis shows that with the Federal Aviation Administration's global positioning system-based Local Area Augmentation System operational and a reliable data link transmitting full state information between aircraft, it is technically feasible to reduce. runway spacing to 1500 ft or less using the same safety criteria as that used for the recently implemented Precision Runway Monitor program.
Measurements of the Global Positioning System carrier phase can provide the basis for the highest level of satellite-based navigation performance. In particular, the potential exists to exceed even the stringent navig...
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Measurements of the Global Positioning System carrier phase can provide the basis for the highest level of satellite-based navigation performance. In particular, the potential exists to exceed even the stringent navigation requirements for aircraft precision approach and landing. The principal difficulty in this use of carrier phase, however lies in the real-time, high-integrity resolution of the unknown integer cycle ambiguities. A new methodology is introduced, using carrier phase measurements from ground-based pseudolites, for explicit estimation of the cycle ambiguities. The mathematical basis of the new approach is detailed, and high-speed nonlinear information smoothing algorithms suitable for real-time airborne execution are derived. Extensive flight-test data, including the results of automatic landings of a Boeing 737 aircraft, are presented as experimental validation of algorithm performance.
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