NovAtel’s Tightly-Coupled Solution

To begin, we can extract NovAtel’s tightly-coupled solution from the ${\it{INSPVA}}$ packet. This solution is depticted below as a ground trace in Figure 1.

Fig 1 :: NovAtel's Tightly-Coupled Ground Trace

Through visual inspection, this solutions looks good. However, to quanity the accuracy of the solution, a RTK solution will be generated.

RTK Solution

To generate the RTK solution, which will be used as a “reference truth” for all later comparisions, the open-soure library, RTKLib, will be utilized. This allows use to incorporate precise obrit/clock products with aditional observablse provided via a basestation to iteratively solve for the platforms location. An overlay of the RTK ground trace is provided below in Figure 2.

Fig 2 :: RTK Ground Trace

Comparison Between NovAtel and RTK

Use the RTK solution generated by RTKLib, we can evaluate the estimate accuracy of the solution provided by the NovAtel SPAN system.

Processing With NASA JPL’s Precise Point Position Libraries

Now, we can processing the data using NASA JPL’s Precise Point Positioning (PPP) libraries.

GIPSY - II

First, we will utilize NASA JPL’s GNSS-Inferred Positioning System and Orbit Analysis Simulation Software package (GIPSY-OASIS). This package has been the primary geodetic and positioning software for several NASA missions.

Pseudorange Only Solution

To provide an initial trajectory for iterative processed PPP solution, we will initially generate a solution that utilizes only the pseudorange observables. The East/North ground trace of this solution is shown below.

Fig 3 :: GIPSY Pseudorange only solution

Iterative PPP Solution

RTGx