As has been mentioned before, this library is for low-level GPS data processing. GPS receivers measure the distance to GPS satellites. Out of the ephemeris data, the satellite positions are calculated, and with the distances, the position of the receiver can be calculated. This is a pretty straightforward process, implemented in every GPS receiver and taught to geodesy students in the first semester. The tricky part is getting the distances. Using the codes (the military P(Y)-Code or the civilian C/A-Code) only yields a distance precision of several meters. Using phase measurements, you can improve your accuracy to a few millimeters, but this requires lots of difficult math (like the cycle slip detections mentioned in the article). GPS receivers who can do this cost 10.000 Euros/Dollars and more. This functionality is also implemented in GPS processing software for geodesy uses, such as SkiPro by Leica and GeoGenius by Trimble. But this software is very expensive.
So what does the average GPS user get from this? Not much - unless you have one of the higher priced Garmin Etrex units, which can do phase measurements, but not calculate a position out of them. What's so special about this is that algorithms previously only available in expensive black-box software are now publicly available. For geodesists, this is just wonderful, like Microsoft opening the Windows source code to computer scientists. So I think this is truly worth a/. article.
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As has been mentioned before, this library is for low-level GPS data processing. GPS receivers measure the distance to GPS satellites. Out of the ephemeris data, the satellite positions are calculated, and with the distances, the position of the receiver can be calculated.
/. article.
This is a pretty straightforward process, implemented in every GPS receiver and taught to geodesy students in the first semester. The tricky part is getting the distances. Using the codes (the military P(Y)-Code or the civilian C/A-Code) only yields a distance precision of several meters. Using phase measurements, you can improve your accuracy to a few millimeters, but this requires lots of difficult math (like the cycle slip detections mentioned in the article). GPS receivers who can do this cost 10.000 Euros/Dollars and more.
This functionality is also implemented in GPS processing software for geodesy uses, such as SkiPro by Leica and GeoGenius by Trimble. But this software is very expensive.
So what does the average GPS user get from this? Not much - unless you have one of the higher priced Garmin Etrex units, which can do phase measurements, but not calculate a position out of them. What's so special about this is that algorithms previously only available in expensive black-box software are now publicly available. For geodesists, this is just wonderful, like Microsoft opening the Windows source code to computer scientists. So I think this is truly worth a
Toby