USGS CMG S-5-10-PS Navigation

 S510PS   Nooksack RTK GPS base station (BEL1) information
 The following information pertains to the GPS base station "BEL1" used for the SWATH bathymetry survey at Nooksack River delta (Bellingham, WA), February 2010.
 The base station was programmed using the following coordinates: (see also "nooksack-base-setup.JPG")
 Reference Frame: WGS84 (G1150)
 Epoch: 2010.1257
 Latitude: N 48 45' 58.65444"
 Longitude: W 122 31' 19.75486"
 Ellipsoid Height: 1.886m
 
 The average values for the derived OPUS solution for "BEL1" are:
 Reference Frame: ITRF00 [same as WGS84 (G1150)]
 Epoch: 2010.1257
 Latitude: N 48 45' 58.65429"
 Longitude: W 122 31' 19.75388"
 Ellipsoid Height: 3.613m
 
 The differences to be added to the RTK broadcast locations are:
 Latitude: -0.00015"
 Longitude: -0.00098"
 Ellipsoid Height: 1.727m
 
 Using UTM coordinates as a comparison:
 The base station was programmed using the following coordinates: 
 Reference Frame: NAD83, UTM zone 10
 Epoch: 2002.0000
 Northing: 5401585.847m
 Easting: 535115.318m
 Ellipsoid Height: 2.207m
 Orthometric Height: 23.780m (based Geoid09)
 
 The average values for the derived OPUS solution for "BEL1" are:
 Reference Frame: NAD83, UTM zone 10
 Epoch: 2002.0000
 Northing: 5401585.842m
 Easting: 535115.338m
 Ellipsoid Height: 3.934m
 Orthometric Height: 25.507m (based Geoid09)
 
 The differences to be added to the RTK broadcast locations are:
 Northing: -0.005m
 Easting: 0.020m
 Ellipsoid Height: 1.727m
 Orthometric Height: 1.727m
 
 2/4/2011 
 Here's the information you requested about the control at Nooksack and Sandy Point.
 
 The Excel file contains all of the OPUS summaries for the Nooksack points occupied.
 
 The primary control at Nooksack was "BEL1". This was the top of a fence post put into a ridge, overlooking the bay.
 Its companion point "BEL0" is a benchmark that I installed in a mass of concrete at the back edge of the grassy lawn, near "BEL1".
 "BEL0" was meant to be permanent while "BEL1" was meant to be a stable point for the duration of the SWATH survey.
 
 You should remember that there is a significant offset (~1.7+m) in the vertical from what I was broadcasting as "BEL1"'s elevation and its actual elevation.
 This was my fault as I didn't catch a software mistake in the post-processing of the original occupation (OPUS wouldn't process the data at the time).
 The actual amounts of offset can be seen at the bottom of the excel sheet for "BEL1".
 As a result, the 1.8m tripod height reverted to 0.000m. The remaining 0.1m was due to a difference in the antenna types used.
 In any case, Dave F. was made aware of this at the time of SWATH processing and should have taken it into account.
 You should verify this with him to be sure. The correct OPUS values for ITRF00 (lat, long, ellipsoid height) should be used in the future.
 
 We occupied two points at Sandy Point; "SP00" and "SP01".
 "SP00" is a benchmark we installed near the shoulder of the road (see attached images).
 It is the primary reference point for Sandy Point
 "SP01" is its companion point and is a bolt on the foundation of an incomplete house near the water (see attached images).
 "SP01" was to be used as a verification point and was not meant to be permanent.
 
 We only occupied these points once but the OPUS values look acceptable.