Propagation Basics: - Signal, tagged with time from satellite clock, transmitted. - About66msec(20,000km) later the signal arrives at GPS receiver. Satellite has moved about 66 m during the time it takes signal to propagate to receiver

Estimation · Summary Examine correlations -Process noise · White noise · Random walk First-order Gauss Markov Processes Kalman filters Estimation in which the parameters to be estimated are changing with time

Examined methods for measuring distances Examined GPS codes that allow a type of distance measurement and phase to be measured Examine how the range measurements are defined Use of carrier phase measurements Examine rinEx format and look at some \raw data

GPS Observables Today's class we start discussing the nature of GPS observables and the methods used to make range and phase measurements Start with idea of remotely measuring distances

Potential field based coordinates: -Astronomical latitude and longitude -Orthometric heights (heights measured about an equipotential surface, nominally mean-sea-level

Coordinate Systems Today we cover: Definition of coordinates - Conventionalrealization of coordinates Modern realizations using spaced based geodetic systems (such as GPS)

so if t is the current time in a real time situation, we cannot compute ()for which is necessary since w, () is nonzero only for>0. But we showed earlier that

where is the linearized system matrix. But this requires the full(same number of equations as finite differencing). In =time when the nominal trajectory

Non-zero power at non-zero frequency If R(r) includes a sinusoidal component corresponding to the component x()=Asin(o41+6) where 0 is uniformly distributed over 2t, A is random independent of 0, that component will be

Summary of the subject (topics) 1. Brief review of probability a. Example applications 2. Brief review of random variables a. Example applications 3. Brief review of random processes a. Classical description b. State space description