RTK uses a fixed base station, ideally you know exactly where it is so that you know the exact location of your mobile unit (else you will at least get a pretty good relative position).
With the new chips, Broadcom, u-blox and others are bringing to market now you are no longer dependend on a base station to get cm-level accuracy.
Instead they exploit the different properties of the L1/L5 frequencies to infer stuff about e.g. the atmosphere, as the different frequencies are altered in different ways while travelling to earth[2]. The system can thus reduce its margins of errors[1] in the position calculations.
So they are not "interacting" with RTK in any way.
The chips are also much cheaper than your quoted $1K price tag.
Disclosure: I work for u-blox, but not an expert in GNSS calculations
Also, RTK requires tracking the carrier phase. And in turns this requires the receiver being kept on all the time, which is power hungry and just not acceptable for low-power / on battery applications.
Whereas the dual frequency approach can be used in the same way as "regular" GNSS, using all the low-power tricks to sleep as much as possible (with some accuracy vs. power trade-offs). Of course there will be a power consumption penalty vs. a single frequency receiver: the two RF chains, and the extra base-band processing. The later can be mitigated by better nodes (the article mention the chip being 28nm, so low dynamic power). The two RF chains impact of course can't be avoided. But for some application it may be worth it.
I guess my question was more specifically can these be used together for even better accuracy? e.g. if standard RTK on L1 is 1-3cm accurate, and L1/L5 is 30cm accurate, will using two of these new L1/L5 chips in an RTK configuration increase accuracy even more (since they are using different methods of error correction) or are there inherent limits to resolution? Appreciate any insight you might have, thanks.
With the new chips, Broadcom, u-blox and others are bringing to market now you are no longer dependend on a base station to get cm-level accuracy. Instead they exploit the different properties of the L1/L5 frequencies to infer stuff about e.g. the atmosphere, as the different frequencies are altered in different ways while travelling to earth[2]. The system can thus reduce its margins of errors[1] in the position calculations. So they are not "interacting" with RTK in any way. The chips are also much cheaper than your quoted $1K price tag.
Disclosure: I work for u-blox, but not an expert in GNSS calculations
[1] https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_... [2] https://www.e-education.psu.edu/geog862/node/1715