Simulation and evaluation of the performance of the proposed Mars network constellation for positioning, orbit improvement, and establishment of a spatial reference frame for Mars
In 1999, the NASA Jet Propulsion Lab presented a proposal for a six satellite navigation and communication network for Mars called the Mars Network. This thesis investigates the performance of the Mars Network both theoretically, using figures of merit commonly applied to satellite navigation systems on Earth, and in the position domain using simulated observations. The Mars Network is evaluated in terms of availability, accuracy, and reliability as a function of position and time by simulating network geometry for users distributed across the planet. The Network is found to provide the best service to users in equatorial and polar regions. Instantaneous positioning is limited due to the small number of satellites in the constellation. The addition of a height constraint is shown to increase the availability of instantaneous positioning. End-to-end simulation tools are developed for the simulation of Mars Network observations. The trajectories of the satellites are precisely modelled using numerical methods. Models are developed and implemented for the most significant error sources, including the effects on the navigation signals of the Mars ionosphere and troposphere. After the effect of orbital errors, the ionospheric effect is found to be the next largest error source. A positioning and orbit determination algorithm is developed based on a decentralized processing strategy that only requires network elements to exchange state vectors and covariance matrices while making observations of each other. The algorithm is tested in several scenarios using a simulated range and Doppler observations between the six Mars Network satellites and eight simulated landers. The ability of the Mars Network to position landers with sparse observations is demonstrated. The Mars Network is shown to be able to position landers on Mars to accuracies of 10 m after several hours of intermittent tracking. The limiting factor is found to be the growth of orbital errors. The ability of current and future lander missions to provide ground control for improving orbits and to improve lander positioning performance is demonstrated. The effect of inter-satellite observations is investigated. Recommendations are given for ways to improve the navigation performance of the constellation and areas of future research are discussed.
Bibliography: p. 175-182
O'Keefe, K. (2004). Simulation and evaluation of the performance of the proposed Mars network constellation for positioning, orbit improvement, and establishment of a spatial reference frame for Mars (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/19212