Contents
Global Positioning Systems
Global Positioning System (GPS) is a technology that can locate positions or navigate the user to a location. GPS uses a constellation of 24 navigational satellites to determine positions on the earth’s surface. Geographic Information System (GIS) is mapping software that can link information about where things are with information about the location, e.g. soil type, vegetation, topography, roads, etc. Combining GPS and GIS can direct tractors, four wheelers, aircraft, or persons on foot to desired field locations. Additionally, these systems can be programmed to direct mechanical operations, e.g. variable-rate sprayers, fertilizers, or seeders, etc. This technology is revolutionizing many agricultural operations.
Description
GPS units consist of a receiver, antenna, display screen, and/or lightbar for tracking. These units can be handheld, carried as a backpack, mounted in mobile equipment, or an integral part of a desktop computer depending on desired application and accuracy. Differential GPS (DGPS) uses a base station or a special signal to supply a correction value to the receiver’s data. This combination can provide accuracy from 30 feet to inches depending on type of equipment. Base stations use post-processing of data. Differential signals for real-time applications include Omnistar (worldwide L-band satellite signal), Landstar (L-band satellite signal), Coast Guard beacon (where available), WAAS (Wide Area Augmentation System), and RTK (Real-Time Kinematic).
Application
GPS units need a signal from at least three satellites for minimal operation. Current handheld units using WAAS are accurate within approximately 10 feet and cost from $150 to $450 depending on options. These units are popular with hikers, hunters, and fishermen. Real-time applications for mobile equipment can cost $10,000 to $40,000 or more depending on accessories. Aircraft units are capable of displaying maps of fields to be sprayed, guiding each swath, and logging the flight pattern of aircraft. Tractors use GPS to control variable rate applications of agricultural materials, and RTK systems are available to accurately steer the tractor. Brush control projects are using GPS to guide tractors or aircraft during applications to protect wildlife habitat, clear selected areas, and provide aesthetically pleasing landscapes.
GPS automated steering.
Photo courtesy BEELINE Technologies, Inc.
GPS unit in an aircraft. GPS Screen with targeted spray area.
Photos courtesy of Charles R. Hart.
Sources
The manufacturers' websites list information on equipment sizes, accessories, dealers, and their email addresses.
AGCO Corporation
4205 River Green Parkway
Duluth, GA 30096
Phone: 770-813-9200
Fax: 770-813-6158
Website:
www.agcocorp.com
Ag-Nav, Inc.
33122 SH 249 Suite A
Pinehurst, TX 77362
Phone: 866-662-4628
Phone: 281-252-8908
FAX: 281-252-8909
Website:
www.agnav.com
BEELINE Technologies, Inc.
1070 West 124th Avenue
Suite 900
Westminster, CO 80234
Phone: 303-457-9333
Fax: 303-457-9394
Website:
www.beeline.ag
Deere & Company (GreenStar)
John Deere World Headquarters
One John Deere Place
Moline, IL 61265
Phone: 309-765-8000
Fax: 309-765-4225
Website:
www.deere.com
ESRI (ArcGIS)
380 New York Street
Redlands, CA 92373-8100
Phone: 800-447-9778
Phone: 909-793-2853
Fax: 909-7935953
Website:
www.esri.com
Forestry Suppliers, Inc. (catalog)
P.O. Box 8397
Jackson, MS 39284-8397
Phone: 800-647-5368
Phone: 601-354-3565
Fax: 601-292-0165
Website:
www.forestry-suppliers.com
Garmin International Inc.
1200 East 151st Street
Olathe, KS 66062
Phone: 913-397-8200
FAX: 913-397-8282
Website:
www.garmin.com
Magellan –Thales Navigation
960 Overland Court
San Dimas, CA 91773
Phone: 800-669-4477
Phone: 909-394-5000
FAX: 909-394-7050
Website:
www.magellangps.com
NovAtel Inc.
1120 – 68th Avenue N.E.
Calgary, Alberta, Canada T2E 8S5
Phone: 800-668-2835
Phone: 403-295-4500
Fax: 403-295-4901
Website:
www.novatel.com
Omnistar Inc.
8200 Westglen Dr.
Houston, TX 77063
Phone: 800-338-9178
Phone: 713-785-5850
Website:
www.omnistar.com
Satloc LLC
CSI Wireless Inc.
7560 E. Redfield Rd. Suite B
Scottsdale, AZ 85260
Phone: 480-358-9919
Fax: 480-348-6370
Website:
www.satloc.com
Trimble
P.O. Box 3642
Sunnyvale, CA 94088-3642
Phone: 800-827-8000
Phone: 408-481-8000
FAX: 408-481-7781
Website:
www.trimble.com