Snapshot: who offers terrain compensation?
A number of companies now offer terrain compensation to increase the value of their GPS guidance and autosteer systems.
Posted: March 16, 2006
One thing producers will have to be familiar with is the jargon of terrain compensation. Here are the three basics
Roll: is the side-to-side rotation of the vehicle, as when traveling along a side slope.
Yaw: is the constant steering of the vehicle up a hill. The correction keeps the vehicle in a straight line.
Pitch: is the front-to-back rotation of the vehicle when traveling up and down hills.
Trimble, Case iH, New Holland Trimble's terrain compensation technology is named T2 and T3. The T2 is available as an option for Trimble's AgGPS EZ-Steer assisted steering system and corrects for roll and yaw.
T3 comes standard with Trimble's AgGPS Autopilot. The T3 corrects for roll, yaw and pitch. The Autopilot system is ideal for applications like row cropping where one inch steering accuracy at any speed is a necessity.
Trimble uses accelerometers and laser gyroscopes to give information to the GPS system regarding the position. Laser gyros measure tilt by constantly referencing points measured to check for differences. For more information go to www.trimble.com or contact your nearest independent dealer.
Trimble GPS equipment can be purchased from independent Trimble dealers or through Case iH and New Holland. Both of which have usage agreements with Trimble.
John Deere John Deere's terrain compensation system is called Terrain Compensation Module (TCM), which is available on all StarFire receivers. The TCM enhances the performance of GreenStar Guidance systems when operating in hilly or rough conditions. The TCM compensates for vehicle roll on the side slopes. TCM functionality is a combination of gyro sensor and accelerometer corrections, which smooth out the position data, resulting in more stable system performance.
John Deere believes so strongly in the benefits of terrain compensation in all situations, that it comes standard with their new StarFire iTC receivers. TCM can be added to original StarFire receivers for those farmers who already have a GreenStar system. For more information go to www.deere.com
Terradox Corporation Terradox has named their terrain compensation technology TRC for use with the SiteWinder GPS Guidance System. TRC has a Dual-Axis Tilt Sensor that continuously monitors terrain errors while driving and even when the vehicle is stopped. The Dual-Axis sensor corrects for pitch and roll terrain errors. The yaw steering correction is integrated into their autosteer system.
Terradox says one big difference in the tilt sensor is that it uses liquid sensor technology instead of the laser gyros of other companies. This is essentially a small glass tube with liquid inside. Electrodes inserted along the tube measure how far they are immersed in the liquid and the data is translated into angle. This is an absolute measurement of angle with the calibration advantage to set it and forget it. For more information go to www.terradox.com
Mid-Tech Mid-Tech's terrain compensation is called Tilt Compensation Module. This module mounts solidly to the vehicle and uses an accelerometer to determine the slope the vehicle is on. Using the preprogrammed antenna height, the module adjusts the position data from the GPS receiver before sending the slope-corrected data to the connected guidance device.
The Tilt Compensation Module features three diagnostic LEDs indicating the status of the module; its power status, operating status and the status of incoming GPS data. It is compatible with CenterLine®, Swath XL and GuideLine guidance systems as well as the Legacy 6000 precision farming system. For more information go to www.mid-tech.com
With the increasing popularity of terrain compensation, more companies are developing options. Expect terrain compensation technology to continue to evolve, say these companies.