Digital phase-locked loop (DPLL) and Kalman filter both have been widely used as the clock tracking and clock correction
schemes for the similar structure and properties.
The satellite clock correction
is calculated based on parameters transmitted in the satellite navigation message.
The accuracies of orbit and clock correction
products and error models to be used in determination have significant importance on the point positioning accuracies to be achieved in PPP method.
To achieve better curve fitting, here, we design the "satellite-clock-aided curve fitting" strategy which applies the satellite clock correction
. First, we extract the high-precision satellite clock information from the International GNSS Service (IGS) clock file.
Car clockers are so blatant that they openly advertise their "car clock correction
" services on the internet.
Caption: Figure 4: RTS clock correction
and prediction result (PRN 08, January 18, 2016).
The REFSV field contains the satellite clock correction
. The software obtains this information in one of two different ways, depending upon the OEM receiver board in use.
We introduced Kalman filter (Strang and Borre, 1997) in the final phase of data processing for dynamic recursive estimation of set of unknown parameters--site coordinates, correction to initial ambiguities and actual receiver clock correction
are given as offsets to the Broadcast Ephemeris satellite clock corrections
Where [[DELTA].sub.C] contains various clock corrections
, r is a vector from the barycentre to the telescope, [??] is a unit vector pointing from the barycentre to the pulsar, c is the speed of light, d is the distance to the pulsar, D is the interstellar dispersion constant,/is the radio frequency, [A.sub.E[?]] is the Einstein delay comprised of the gravitational red shift and time dilation, [[DELTA].sub.S[?]] is the Shapiro delay characterising the curvature of space time near the Sun and [[DELTA].sub.A[?]] is the aberration delay as a result of the Earth's rotation (Bell, J.F., 1996; Kaspi V.M; Lorimer D., 2008)
The StarFire system uses a network of more than 50 GPS reference stations around the world to compute GPS-satellite orbit and clock corrections
. These corrections are broadcast via three geosynchronous satellites to the GPS receiver, enabling precise real-time navigation without the need for a ground base station.