Farmers who have long used precision ag tools remember the early days of setting up a tower in a field corner to get that super-precise real-time kinematic, or RTK, correction signal. Over time, that evolved to a tower on a high spot in the region for that correction. In recent years, that tower has gone away for some systems, yet sub-inch accuracy continues and for Trimble the process has been improved again with a new update.

"We've been continually improving our CenterPoint RTX system over the past 10 years, but this is the biggest change for Trimble Ag and RTX in terms of positioning performance we can achieve," says Michael Bruno, strategic marketing manager for ag correction services, Trimble.

A challenge with satellite delivered correction services is convergence, which is the process the in-machine system uses to “see” satellites to provide correction. That process can take up to 20 minutes before you roll in a field. The Trimble upgrade, which includes adding access to a new constellation of satellites, cuts that time by 75%.

"There are two big improvements," Bruno says. "In the tractor receiver, we have new ProPoint technology with a new positioning engine and algorithms the autoguidance can use. And we've added multiple satellites with our RTX algorithm, increasing the amount of satellites we can use now."

Tapping GPS constellations

The world is "covered" by different GNSS satellite constellations — often generically referred to as GPS, since this was the first system launched by different countries, — and all use a similar frequency. The industry long ago added GLONASS satellite coverage, which is the satellite constellation launched by Russia. Trimble has also added the Galileo, which is the European constellation. But for this latest update, Trimble is now accessing the BeiDou-III constellation recently powered up by China.

"We've increased the number of satellites the system uses in its calculations by 25%," Bruno explains. "That's what helps reduce the convergence time, and provide robustness in the field and around obstacles. And we improved the algorithm in ProPoint to bolster that."

With this system, you can get horizontal RTK sub-inch accuracy without the need for a stationary tower correction signal. "It takes out the complexity of the system," Bruno says. "No tower, no radio into the receiver."

This latest upgrade is designed for the Trimble NAV-900 Guidance Controller receiver and involves a relatively simple firmware upgrade. Bruno says tech-savvy farmers can do that themselves with a flash drive, or have their local dealer implement the process. The price for the service is not changing; if you have a subscription, you simply upgrade the software to get improved performance.

"With the NAV-900, using those constellations and the new ProPoint software, you could go from 'seeing' roughly 20 to 25 satellites to well over 30," Bruno says. And with GPS systems, the more satellites the receiver can use, the better overall performance.

You can learn more about the upgrade by visiting Trimble Positioning Services online.