I have a Bad-Elf Surveyor (with what I’m pretty sure is a ublox Neo-7P module) and am experimenting with the kind of accuracy I can get from it by collecting raw data logs (RINEX) from the Bad-Elf app. I’ve figured out how to apply post-processing corrections using RTKLib’s RTKPost, which I’ve described at What will post-process differentially correct raw Bad-Elf Surveyor U-Blox NMEA/raw UBX?.
The Bad-Elf page claims that optimal accuracy can be achieved by implementing GPS+PPP+SBAS. The ublox page says, “u‑blox’ PPP technology is made possible by stabilizing measurements of the distance between GNSS satellites and the receiver (pseudo‑ranges) using carrier phase tracking. Additional accuracy is achieved from ionospheric correctional data received from satellite‑based augmentation systems.” The NEO-7P product page says that “u‑blox has implemented PPP in its NEO‑7P GNSS module.” (Emphasis mine.)
The Bad-Elf statement seems to imply that optimal accuracy requires that data be collected while WAAS/SBAS corrections are being received and implemented by the receiver itself and subsequently post-processed using PPP (ephemera and clock inputs). The ublox page seems to suggest that should post-processing should be done with clock and ephemera files, and then the SBAS information used for ionosphere corrections. The 7P product description seems to suggest some sort of mysterious internal PPP algorithm correcting the position readings in the chip itself.
Does anyone know which, if any, of the above three concepts is correct?