A perfect duality exists between the problem of space-based orbit determination from line-of-sight measurements and the problem of designing an interplanetary autonomous navigation system. Mathematically, these two problems are equivalent. Any method solving the first problem can be used to solve the second one and, vice versa. While the first problem estimates the observed unknown object orbit using the known observer orbit, the second problem does exactly the opposite (e.g. the spacecraft observes a known visible planet). However, in an interplanetary navigation problem, in addition to the measurement noise, the following "perturbations" must be considered: 1) light-time effect due to the finite speed of light and large distances between the observer and planets, and 2) light aberration including special relativistic effect. These two effects require corrections of the initial orbit estimation problems. Because of the duality problem of space-based orbit determination, several new techniques of angles-only Initial Orbit Determination (IOD) are here developed which are capable of using multiple observations and provide higher orbit estimation accuracy and also they are not suffering from some of the limitations associated with the classical and some newly developed methods of initial orbit determination. Using multiple observations make these techniques suitable for the coplanar orbit determination problems which are the case for the spacecraft navigation using visible planets as the solar system planets are all almost coplanar. Four new IOD techniques were developed and Laplace method was modified. For the autonomous navigation purpose, Extended Kalman Filter (EKF) is employed. The output of the IOD algorithm is then used as the initial condition to extended Kalman filter. The two "perturbations" caused by light-time effect and stellar aberration including special relativistic effect also need to be taken into consideration and corrections should be implemented into the extended Kalman filter scheme for the autonomous spacecraft navigation problem.

Cathedrals today are no longer sites of just religious worship, they must be many things to many people such as tourist attractions, heritage centres, and meeting places. Today, Durham Cathedral in the north-east of England is home to almost 900 people engaged on site, of which almost 700 are volunteers. Add to that number over 700,000 visitors and about 1,700 religious services annually, and a complex image of life within Durham Cathedral begins to take shape. Drawing on 14 months of ethnographic fieldwork between August 2013 and September 2014, this thesis takes a phenomenological approach in exploring the dynamic relationships that exist between a 900-year-old building and those who regularly come into contact with that building. It will consider the complex negotiations that take place between the many parts of the community and the building in a constantly changing environment, and will focus on the role sound, light, time, and space play in the constant challenge of change and negotiation. Finally, it will consider how buildings are not only constructed but are also cultivated through being built and rebuilt, spaces negotiated and improvised, as well as filled with stories and memories. The importance of this research is not just in observing and understanding the types of change and negotiation that occur between a building and those who inhabit it, but also in understanding the altering roles of religious buildings as they cope with the changing demands of running a site of both historical and continuing social, religious, and financial pressures, Durham Cathedral is a place that gives space to differing communities, allowing people to find in the building what they need from the building and as a result of this, Durham Cathedral is not a place in which life happens, it is a place with which life happens.