[yaantc]

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.