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Australia | The mojoRTK has been initially designed for use with a portable or fixed RTK base-station (provided). This will give the user up to 16miles radius of 'baseline' coverage with no subscription fees. Leica has one of the longest operating RTK baselines on the market. Dual Frequency RTK is by definition a 'repeatable' or "no-drift" solution. Even L1 RTK is repeatable but it has many other limitations that affect its reliability and ultimate usefulness including a poor baseline range.
Many people get RTK 'GPS baseline' range mixed up with RTK 'radio link' range. They are two very separate issues. The best way to think about it is to imagine a cable connecting the base to the machine, transporting the necessary RTK data from the base. Even if this cable was long enough that the machine could drive beyond 16 miles, the mojoRTK would begin to lose accuracy because it has moved outside of its baseline limits. The 900Mhz RTK radio link in the mojoRTK is simply a more practical method of connecting the base to a moving machine than a cable. So even if the 900Mhz radio maintained a perfect link beyond 16miles, the mojoRTK would still lose accuracy because it is still outside its baseline limits. In thinking about range you need to consider 'GPS baseline' issues as separate from RTK link radio line-of-sight issues. Cell networks or even sat phone networks may solve the radio line-of-sight issue, but ultimately the performance of any RTK system will depend on the distance from your base-station or a CORS base-station (baseline) and the time it takes for the data to get to the machine (over the link radio or cell radio).
The mojoRTK also has a CDMA cell modem built in for remote service so problems can be diagnosed and fixed quickly. It is entirely feasible that this modem could be used to connect to a CORS system (of any brand including Leica's) to receive RTK data which would mean you would not have to purchase a base-station. You would have to weigh-up any cell data charges or CORS fees to determine which is a better deal over time. Run two machines off one base and it is hard to justify paying every year for RTK data.
There are two main companies that provide CORS infrastructure around the world. Trimble and Leica.
Another, misconception is that 'waypoints' or the field starting points are required to be stored for 'repeatability'. Storing waypoints is an attempt to make managing repeatability easier. For a CORS network or fixed base-station solution this can be true, but things get very complicated using a portable RTK base. 80% of RTK users’ battle with waypoint storage for a year then abandon the practice because of the management difficulty (explaining why is another post). They end up simply putting their tires back in the lines, or at a fixed mark, and resetting their waypoints each season to make it workable. Because they have true RTK, this is absolutely repeatable across the field, year-on-year, even though they never store waypoints. In non-RTK systems, 'position drift' makes true repeatability (year-on-year) statistically unlikely unless you are happy with 1.5 to 4ft accuracy.
I know this is long-winded, but I hope I have explained things reasonably well as it is a complex topic and is mostly poorly understood at the point of sale.
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DG N. AL - RTK & correction via cell phone?
