Time Delay of Arrival Location Assessment Using Four Satellites

摘要

The Time of Arrival (TOA)/Time Delay of Arrival (TDOA) concepts for locating a source are reviewed. The Vela satellite program and how they used in conjunction with the TOA concept is discussed. NAVSTAR/GPS is reviewed next and how this interrelates with the other concepts discussed is mentioned. The last concept mentioned is that of nuclear detection. Again, examples on how this idea interrelates with the previous mentioned concepts are shown. The problem addressed here is to develop mathematical formulas that describe the problem of having four satellites viewing an event. The first method uses a TOA technique to solve for the event's location and time. The second method employs the solution from the first method to predict uncertainty in location and time. Also this uncertainty is determined through the use of implicit differentiation. These results are then compared with the projected difference from the standard solution when the associated value is varied by an equivalent amount, in the first method. Results from one example are discussed. (Author)