3 ms·

Dual frequency mitigates the ionospheric delay error of GPS signals, yielding more accurate measurements.

snovv_crash 4y ago
This. Adding a second channel means that without RTK/PPK you can get ~30cm precision. The rest is just technical details.
- lucb1e 4y ago
  For others who are not into that lingo, RTK/PPK are Real-Time and Post-Processed Kinematics. I had an idea of what the word kinematics means (Wikipedia says "describes the motion of [(groups of)] points") so this sounds like you use the accelerometer and gyroscope in addition to GNSS to get better accuracy, but actually no this has nothing to do with measuring your motion. Instead, RTK is something about signals' phase and requires an additional ground station (sounds similar to differential GPS, but by looking at phase data rather than position offset?), and PPK is never mentioned on Wikipedia and I don't understand descriptions from other sources. Post-processing is mentioned in differential GPS, however, to make the difference between the two topics (DGPS, RTK/PPK) even more confusing. If you could elaborate, I'd be interested. It seems very specialistic (though you drop it as if it should be obvious) so I doubt most people here know the terms.
  - snovv_crash 4y ago
    PPK uses exactly the same processing method as RTK, except rather than process in real-time it just logs the information and the merges with afterwards with the data logged from a base station. This is used primarily for remote sensing applications where centimeter accuracy of data is only needed in postprocessing and not at capture time - eg. drones with cameras for 3D reconstruction. The reason to use PPK is weight and cost - it just uses a normal GPS receiver and doesn't need an RTK sideband antenna, since the base station information can be downloaded over the internet at postprocessing time. RTK/PPK gives ~3cm precision, while standard GPS gives 6m precision. This new dual-band giving 30cm precision means it is good enough to not use RTK/PPK except in the most demanding applications.

This. Adding a second channel means that without RTK/PPK you can get ~30cm precision. The rest is just technical details.

lucb1e 4y ago
For others who are not into that lingo, RTK/PPK are Real-Time and Post-Processed Kinematics. I had an idea of what the word kinematics means (Wikipedia says "describes the motion of [(groups of)] points") so this sounds like you use the accelerometer and gyroscope in addition to GNSS to get better accuracy, but actually no this has nothing to do with measuring your motion. Instead, RTK is something about signals' phase and requires an additional ground station (sounds similar to differential GPS, but by looking at phase data rather than position offset?), and PPK is never mentioned on Wikipedia and I don't understand descriptions from other sources. Post-processing is mentioned in differential GPS, however, to make the difference between the two topics (DGPS, RTK/PPK) even more confusing. If you could elaborate, I'd be interested. It seems very specialistic (though you drop it as if it should be obvious) so I doubt most people here know the terms.
- snovv_crash 4y ago
  PPK uses exactly the same processing method as RTK, except rather than process in real-time it just logs the information and the merges with afterwards with the data logged from a base station. This is used primarily for remote sensing applications where centimeter accuracy of data is only needed in postprocessing and not at capture time - eg. drones with cameras for 3D reconstruction. The reason to use PPK is weight and cost - it just uses a normal GPS receiver and doesn't need an RTK sideband antenna, since the base station information can be downloaded over the internet at postprocessing time. RTK/PPK gives ~3cm precision, while standard GPS gives 6m precision. This new dual-band giving 30cm precision means it is good enough to not use RTK/PPK except in the most demanding applications.