Вот, нашел то, о чем говорил.
http://www.colorado.edu/geography/gc...gps/gps_f.html

GPS Techniques and Project Costs

Receiver costs vary depending on capabilities. Small civil SPS receivers can be purchased for under $200, some can accept differential corrections. Receivers that can store files for post-procesing with base station files cost more ($2000-5000). Receivers that can act as DGPS reference receivers (computing and providing correction data) and carrier phase tracking receivers (and two are often required) can cost many thousands of dollars ($5,000 to $40,000). Military PPS receivers may cost more or be difficult to obtain.

Other costs include the cost of multiple receivers when needed, post-processing software, and the cost of specially trained personnel.

Project tasks can often be categorized by required accuracies which will determine equipment cost.

* Low-cost, single-receiver SPS projects (100 meter accuracy)
* Medium-cost, differential SPS code Positioning (1-10 meter accuracy)
* High-cost, single-receiver PPS projects (20 meter accuracy)
* High-cost, differential carrier phase surveys (1 mm to 1 cm accuracy)

Правда, в цене ошибся на порядок.