With the new guidance technology, receivers are able to receive signals from at least one additional satellite system besides the U.S.-developed GPS system. As a result, companies now use the generic term Global Navigation Satellite System (GNSS) to describe them.

Although GPS continues to be the workhorse for navigation systems in the U.S., many new top-end receivers also capture signals from the Russian GLONASS satellite system. Some also are ready to work with the European Galileo system just getting off the ground.

Being able to access navigation signals from multiple satellite systems will make guidance systems more robust, with fewer dropouts along tree lines and other obstructions.

Both Topcon and Trimble have introduced new second-generation receivers for 2009. Both companies previously offered GNSS receivers, which were used primarily for land-leveling applications. Leica's mojoRTK receiver also offered GPS/GLONASS capability when introduced in 2007.

Integrated and upgradable The latest navigation systems package more components together to simplify installation, reduce costs and build in extra features that allow systems to be upgraded down the road.

Topcon's new AGI-3 receiver packages the antenna, receiver and controller in a compact package designed to be moved easily from vehicle to vehicle. The receiver, which will be used in AGCO's new Auto-Guide2 system, will automatically recognize various vehicles in AGCO's lineup, simplifying the move from vehicle to vehicle.

Trimble's new FmX display takes integration in another direction. Except for an external antenna, the display contains the necessary navigation system hardware, including two satellite receivers. The second receiver can be activated to guide an implement steering or land-leveling system.

Topcon and Trimble didn't invent this trend. To varying degrees, new products in recent years from virtually all guidance system manufacturers have packaged various components together.

Touchy-feely Satellite navigation is not the only game in town. Last fall, John Deere introduced its AutoTrac RowSense steering system, which uses a pair of steel whiskers mounted on the corn head to help refine steering on AutoTrac-steered Deere combines.

Now Reichhardt Electronic Innovations, a relative newcomer to the U.S. market, is offering a range of guidance systems using tactile, sound and mechanical sensors. The systems are designed to improve steering of sprayers, combines and other vehicles that need to cope with the challenges of using satellite guidance in the real world of planter drift.

Falling costs The cost of guidance continues to fall for both high-end and low-end systems. RTK systems that cost $50,000 a few years ago now cost half that much. In many cases, new receivers, displays and lightbars have more capabilities than in the past, but cost the same or less.

Here's a look at some of the newest guidance products and capability upgrades, including receivers, displays, lightbars and mechanical sensors.