Results of Real-Time Kinematic Positioning Based on Real GPS L5 Data

The Global Positioning System (GPS) is currently being upgraded from a dual- to a triple-frequency constellation. Although a full triple-frequency constellation will not be realized before 2021, we can already make use of these new signals for positioning. This letter presents the initial results of real-time kinematic (RTK) ambiguity resolution and positioning based on real L5 measurements combined with L1 and L2C measurements. The L2C is the new second civil signal that is like L5, also transmitted by the GPS Block IIF satellites. The results, obtained for a zero baseline and short baselines between some MGEX receivers, demonstrate that the L5 data indeed improve the time-to-first-fix ambiguities, with 24%–49% with respect to dual $\text{L}1+\text{L}2\text{C}$ , to, on average, less than 1 min based on $\text{L}1+\text{L}2\text{C}+\text{L}5$ with four to five satellites. It is also shown that single-frequency RTK is performing better when, instead of L1, the L5 frequency is used, provided that the baseline is not too long. Positioning accuracy, especially the float, is improved when going from dual- to triple-frequency measurements, despite the large position errors that occur at some times, caused by a poor geometry based on only four satellites. In the near future, with more Block IIF satellites launched, these geometry defects will occur less frequently.