iGage iG9 User Manual
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Horizontal and Vertical Datum; Geoid model choice
Survey style: OPUS-Static, OPUS-Rapid Static, OPUS-Projects
Consider FGDC Standards:
http://www.fgdc.gov/standards/projects/FGDC-standards-projects/accuracy
Are there passive marks available for control?
Will CORS, passive or a combination control the survey?
Are local passive marks recoverable, undisturbed, sufficient quality, stable and GPS
friendly?
Where are the nearby NGS CORS (active) marks? This will determine ‘Rapid Static’ or
‘Static’ availability.
OPUS-Rapid Static Requirements
Find the closest 9 CORS sites with available observations
A minimum of 3 CORS stations within 250 KM are required.
Your site must be within 50 km of a polygon created by the remaining available CORS.
If the eligible CORS count is low, check the past reliability of recent observations to ensure
that there is a high probability of sufficient sites for OPUS-RS to compute a solution. Use
the CORS ‘Data Availability’ to check for recent observations:
Mission Planning: Satellite Availability and Network Planning
How many receivers will you use for simultaneous observations? If you are using OPUS-
Projects then More = More-Better.
Checkout online ‘Mission Planning’ tools for U.S. satellite availability using
reasonable
masks (>15 degrees) during collection periods. If there are any periods with fewer than 6
SV’s or PDOPS higher than 3, plan on occupying points longer.
How long will you observe a site? Again:
Are your sites GPS compatible? Are there obstructions higher than 10 degrees?
