The proposed GDE System management plan is to 
license regional franchise affiliates which are linked 
with imagery reception sites. These regional partners 
will maintain local imagery archives and provide value- 
added image product and distribution capabilities. 
The primary processing center and master archive will 
be managed by GDE in the USA. Their plan is to 
provide Internet accessibility and two-day delivery 
from time of image acquisition. The product suite 
plan is to provide system corrected images; geometric 
corrected images; monoscopic scenes tailored to 
customer needs; stereo image pairs; DTM's; 
orthophoto and special image products; and volume 
discounted pricing. 
RESOURCE 21 
Resource 21 is a commercial remote sensing 
information systems and services company which has 
obtained a commercial license to develop and operate 
a constellation of ten meter resolution multispectral 
satellites for initial operational capability in the early 
months of 1999. Resource 21 was created in 1994 by 
the Institute of Technology Development (ITD) based 
on four years of market testing of an aircraft-based 
remote sensing product. Resource 21 is now a 
coalition of six business partners which are designing 
their system to support the growing "precision 
farming" industry. Dr. Herb Satterlee is President of 
Resource 21 which has offices in Gulfport, Mississippi 
and Denver, Colorado. 
Precision farming is the determination of precise field 
conditions for managing the dispensation of precise 
nutrients to precise locations for improvement of crop 
productivity. 
In October 1996, Resource 21 will make a go-ahead 
decision to begin construction of five satellites. Its 
initial constellation will have four satellites in orbit by 
early 1999. The four satellites will be placed in exactly 
the same orbital plane, but with tightly controlled 
phasing. The phasing will result in two satellites in 
each of two ground tracks that repeat every seven 
days. Each of the two satellites within a particular 
ground track revisit, with the same access geometry, 
the same ground sites every third or fourth day. This 
strategy results in twice weekly "nadir" access revisits 
of all sites. 
The multispectral, pushbroom sensor called "M10" is 
nominally designed for nadir collection of 205 km 
swaths, but it has adjustable line rates to 
accommodate off-nadir collection. The spacecraft bus 
can roll or tilt the sensor allowing stereo imaging and 
frequency of site revisits up to three times daily! The 
spatial resolution of the MS system is 10m (1/40th 
acre) nominally designed to provide precise monitoring 
of V4 acre sites for 180 acre or larger farms. Precision 
digital processing of the MS bands (e.g. band ratio 
comparisons) provides information about the temporal 
condition of crops and soils for frequent remote 
monitoring of localized variations in site conditions 
such as; moisture content, pest and weed infestations, 
and nutrient needs. 
With the use of ground control points, it is projected 
that spatial accuracies of better than 5 m absolute and 
1 m relative can be provided. A site/region specific 
GIS will maintain site condition history. This potent 
combination of information allows timely allocation of 
water, fertilizer, pesticides, etc. thereby vastly 
increasing site productivity. The system is ideally 
suited for agricultural sites which use farm equipment 
instrumented with GPS. A pilot program using 
airborne MS sensors, conducted since 1991, includes 
more than 180 "beta" sites in six states to demonstrate 
the effectiveness of approach. Future efforts to 
expand into non-agricultural markets are under 
consideration. 
Table 8 provides a summary of the Resource 21 
technical and operational characteristics. Resource 21 
is offering: Products - data, information, and tools; 
Services - custom processing, special studies, training, 
and delivery; and Ordering Options - subscriptions, 
archive retrievals, standard information products, 
custom area quantity and shapes, custom and standard 
formats. The ground processing system is designed to 
provide twice weekly information products to 
subscribing customers within two to six hours after 
image acquisition! Typical costs are $6 to 15 per acre 
cost to the farmer, wherein the price is set per value 
per crop grower type. 
OTHER PROPOSED SYSTEMS 
Although system plans and technical specifications are 
not available at this time, another commercial remote 
sensing satellite system is under development by the 
Geophysical & Environmental Research Corp. (GER) 
of Millbrook, New York. The GER Earth Resource 
Observation System "GEROS" will include a 
constellation of six simultaneous satellites each 
carrying a 10m MS and < 10m pan digital sensor. 
GEROS is being developed for the agricultural market 
with initial emphasis for precision farming. 
Other non-USA commercial digital Earth observing 
systems have been under consideration in several 
countries such as South Africa, Israel, and Russia. 
However, except for the Greensat Program of South 
Africa, most are being funded by governments rather 
than totally funded by private organizations. 
278 
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