Transcript Hight Accuracy GPS Mapping and VRS

High Accuracy GPS
Mapping and VRS
Lanny Schnipper
Seiler Instrument
2008 IGIC Conference
Indianapolis, IN
Seiler
VRS in Action
• No base setup
–
–
–
–
get to the job
dial in
Check
start working
• MWRTK VRS in Indiana
– save time
– save money
Overview
• Review GPS
• Discuss use of Virtual Reference
Stations (VRS)
• Obtaining highly accurate GIS/GPS
positions
• Continuously Operating Reference
Stations (CORS)
• Real-Time differential results
What is VRS?
• GPSNet, DGPSNet, RTKNet
• Links a network of reference stations
• Provides quality control of incoming
data
• Logs files for post-processing
• Network modeling of systematic
errors
• Real time broadcast of true network
DGPS and RTK solutions
VRS Data Flow
Reference stations
data streams back
to the server
through LAN,
Internet, or radio
links
VRS Data Flow
User’s receiver
sends an NMEA
string back to
server using
cellular modem.
Virtual Reference
Station position is
established.
VRS
NMEA—GGA
VRS Data Flow
Server uses VRS
position to create
corrected
observables and
broadcasts them
to the user end.
VRS
Why use VRS?
• Eliminates the need for Users to
establish DGPS base/reference
station(s)
• More reference stations = shorter
vectors/ baselines
• Shorter baselines = less atmospheric
errors
• Network atmospheric modeling
• Extended operating range with
improved accuracy
Why use VRS?
• VRS provides integrity monitoring
• All users in common, established
coordinate frame
• Eliminates the dependency on single
base/reference station
– Graceful degradation should a reference station
fail
• Uses established communications
Indiana MWRTK
26 Stations
…and growing!
Indiana MWRTK
www.mwrtk.net
Real Time in TerraSync/ArcPad
• External correction source
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Data radio
Beacon-on-a-Belt (BoB™) receiver
GeoBeacon
SBAS (WAAS)
• TerraSync Version 2.30 (2/03) added
VRS
– Network VRS
– Single base
• GPSCorrect Version 1.1 (4/05)
Support VRS corrections
• GeoExplorer CE series with GPS
firmware version 1.03:
– GeoXT
– GeoXM
– GeoXH
• GPS Pathfinder with firmware version
1.52 or later:
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GPS Pathfinder Power
GPS Pathfinder Pro XRS
GPS Pathfinder Pro XR
GPS Pathfinder ProXH
GPS Pathfinder ProXT
Connecting to VRS
• Internet connection to the VRS server
– GPRS-capable cellphone
– WiFi Hotspot
• Serial cable connection
– Data radio
Outside TerraSync
• Start  Settings  Connections
– Make connection to your Phone or other
device
– Test Internet Explorer to insure connection
was successful
Inside TerraSync
• Start TerraSync
• Select Setup section
• Set Real-time Settings
– Choice 1 field select External Source.
•
Configure the external source
– From the Type field, select VRS
– or select the Single Base option
– Connection Method field, select Internet
– Address field, enter the IP address or URL of the
VRS server.
– IP Address: 64.123.250.18
– IP Port: 2101 for MWRTK
for MWRTK
Accuracy
• Submeter with a GeoXT/XH
– Usually subfoot
– We have even seen less than 6 inches!
– No post-processing required
Subscription
• VRS is a paid subscription
• Seiler provides Logon and password
• MWRTK.NET
– Single Day - $20 per day, 3-day minimum per
month maximum monthly charge $200
(Billed monthly)
– Single Month- $150
(Billed monthly and payable in advance)
– Single Quarter- $375 ($125 per month)
(Billed quarterly and payable in advance)
– One Year- $1,200
(Billed $225.00 per quarter and payable in advance)
Questions?
Seiler