Monday, February 20, 2012

Low cost RTK performance round-up

Having done quite a bit work since the first Yuan10 was built, I think it's time to write a small summary.

I recently put up a navXperience 3G+C antenna that will serve as reference for all future RTK work in this area. With the support of the reference station University of Pisa and their reference observations at 0.2Hz I run RTKLIB (RTKNAVI and RTKPOST) for several days using several low-cost receivers that I assembled.
This should be somehow considered the best possible scenario, having a short 1.5Km baseline.. nevertheless the results are quite exciting I believe.

Figure 1: Yuan10: Skytraq S1315F-RAW

The plots above show solving of the integer ambiguities in about 5 minutes and reaching an accuracy of about 4cm square.

Figure 2: Rappen10 mMCX version: uBlox NEO-6P (RTK mode)

Again, the NEO-6P brings the position down to 4cm square accuracy in less than 10 minutes.

Figure 3: Denga10: NVS NV08C-CSM

The NV08C-CSM solves the carrier phase integer ambiguities and also brings down the accuracy to about 4cm square.

Each of these receivers has his specialty:
  • the S1315F-RAW has 20Hz raw measurements update rate, which is still unmatched performance by other low-cost receivers
  • the uBlox NEO-6P has integrated PPP for high accuracy standalone mode, no other low-cost receivers claims that
  • the NVS NV08C-CSM has Glonass!

P.S.: I attached a trimmed version of the data used to obtain these results here. Please note how the NVS observations are covered by NDA and therefore not included.

P.P.S.: The latest FW from NVS (dated 27 Feb 2012) improves dramatically the quality of the NV08C-CSM raw measurements: results above are not representative anymore.