Real time kinematic (RTK) global positioning system (GPS) technology is integrated with precision farming methodologies to provide highly accurate seeding, cultivating, planting and/or harvesting operations. RTK GPS systems are used to control fully or semi-autonomous vehicles in these operations and may allow for precision planting of seeds (e.g., from a seeder equipped with an RTK GPS receiver and related equipment) and/or precision weed removal (e.g., using a vehicle fitted with weed eradication mechanisms such as augers and/or herbicide sprayers). Crop specific fertilizer/pesticide application is also enabled through the use of centimeter-level accurate positioning techniques.

Methods and apparatus for precision agriculture operations utilizing real time kinematic global positioning system systems

A method for steering an agricultural vehicle comprising: receiving global positioning system (GPS) data including position and velocity information corresponding to at least one of a position, velocity, and course of the vehicle; receiving a yaw rate signal; and computing a compensated heading, the compensated heading comprising a blend of the yaw rate signal with heading information based on the GPS data. For each desired swath comprising a plurality of desired positions and desired headings, the method also comprises: computing an actual track and a cross track error from the desired swath based on the compensated heading and the position; calculating a desired radius of curvature to arrive at the desired track with a desired heading; and generating a steering command based on the desired radius of curvature to a steering mechanism, the steering mechanism configured to direct the vehicle.

Satellite based vehicle guidance control in straight and contour modes

An automatic steering system and method are provided for a vehicle including an hydraulic primary steering system. The automatic steering system includes a guidance module with a GPS receiver and a microprocessor adapted to process and store GPS data defining travel paths, which can be associated with a cultivated field in an agricultural vehicle application. An automatic steering module is connected to the guidance module and to a steering valve control block, which provides pressurized hydraulic fluid in parallel with the vehicle's primary hydrostatic steering system. The automatic steering system utilizes a constant factor, such as steering rate, for predictability and simplicity in the operation of the automatic steering system. A feedback loop from the vehicle hydrostatic steering system uses the vehicle's actual turning rate for comparison with a desired turning rate. The system is adapted for original equipment installation and retrofitting on vehicles, such as farm tractors, with various primary hydrostatic steering system configurations. An automatic steering method includes the steps of: initializing the system; adjusting the steering with an hydraulic valve to provide a constant steering rate; providing feedback corresponding to the vehicle's actual turning rate and combining the feedback with other input signals to provide automatic steering.

Automatic steering system and method

A global navigation satellite sensor system (GNSS) and gyroscope control system for vehicle steering control comprising a GNSS receiver and antennas at a fixed spacing to determine a vehicle position, velocity and at least one of a heading angle, a pitch angle and a roll angle based on carrier phase position differences. The roll angle facilitates correction of the lateral motion induced position errors resultant from motion of the antennae as the vehicle moves based on an offset to ground and the roll angle. The system also includes a control system configured to receive the vehicle position, heading, and at least one of roll and pitch, and configured to generate a steering command to a vehicle steering system. The system includes gyroscopes for determining system attitude change with respect to multiple axes for integrating with GNSS-derived positioning information to determine vehicle position, velocity, rate-of-turn, attitude and other operating characteristics. A vehicle control method includes the steps of computing a position and a heading for the vehicle using GNSS positioning and a rate gyro for determining vehicle attitude, which is used for generating a steering command. Alternative aspects include multiple-antenna GNSS guidance methods for high-dynamic roll compensation, real-time kinematic (RTK) using single-frequency (L1) receivers, fixed and moving baselines between antennas, multi-position GNSS tail guidance (“breadcrumb following”) for crosstrack error correction, guiding multiple vehicles and pieces of equipment relative to each other and earth-moving equipment and method applications.

Gnss guidance and machine control

A navigation system (20) permits the user to designate certain roads or area to avoid when planning a route. The navigation system generally includes a database (28) of road segments and a cost associated with the road segments, such as estimated time or travel across that road segment and estimated length of travel across that road segment. The navigation system (20) determines a route from a selected beginning point to a desired destination by evaluating the cost of the road segments to be traveled in several potential routes and recommends the potential route having the lowest total cost. The user can selectively modify the cost of selected road segments to indicate a preference or avoidance of such roads. By increasing the cost of a road segment, the navigation system (20) is less likely to recommend a potential route which includes that road segment. Similarly, by decreasing the cost of a selected road segment, the navigation system (20) is more likely to recommend a potential route which includes that road segment.

Navigation system with user definable cost values

A method and apparatus for continuously prompting a pilot to manually control and guide a vehicle along a selected line segment of a pattern of coverage of a target area. An on-board receiver and computer receives navigation reference signals, computes navigation parameters and generates navigation signals to an indicator. The indicator is placed within the normal forward field of outside vision of the vehicle's pilot. In a virtual flagman mode, the indicator has lower and upper horizontal lightbars on which discreet lights are illuminated to the left or right of the centerpoint to simulate the relative lateral position of actual flagmen at the beginning and end points of the line segment being tracked. In a flight director mode, the indicator shows a composite sum of factored navigation parameters including angle of intercept between the line segment and vehicle track, perpendicular distance of the vehicle from the line segment, and rate of turn of the vehicle, as a control instruction to the pilot. The system may include audible tone or voice prompts as well.

Michael E. Gvili

Papers

Lane guidance system