Spatial Services
CORSnet-NSW User Guide
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What is a CORS?
Most people are now familiar with the
use of Global Navigation Satellite
Systems (GNSS) like the ones used
for in-car and handheld navigation.
They calculate position using signals
from GNSS, such as the United
States’ Global Positioning System
(GPS), and have an accuracy of
somewhere between a few and a few
hundred metres. This relatively poor
accuracy is the result of minute
errors in the satellite orbits, the
clocks installed in the satellites and
receivers, as well as the tendency for
the earth’s atmosphere to bend or
delay the GNSS radio signal. There
are, however, GNSS receivers used
by surveyors and researchers which
can be used to accurately calculate
position at the centimetre level. To
obtain this accuracy these receivers
need to be able to include
sophisticated error corrections in
their position calculations.
Short for Continuously Operating
Reference Station, a CORS is a high
precision GNSS antenna/receiver set
on a stable monument and
connected to uninterruptable power
supply and secure communication
facilities. Logging position data
continuously, the CORS are used to
generate the information needed by
high precision GNSS receivers for
error corrections in real-time or post
mission.
CORSnet-NSW
DFSI Spatial Services has invested
in rolling out CORS across NSW to
form a network for state-wide precise
positioning. The rollout will reach 200
stations in 2017 including 11 stations
as part of the national AuScope
network.
CORSnet-NSW network as of July 2016
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Table of Contents
Glossary of Terms ......................................................................................................... 4
Web Portal Instructions ................................................................................................ 5
Logged Out Environment......................................................................................... 5
Logged In Environment ............................................................................................ 6
Real-time Instructions ................................................................................................ 12
Using CORSnet-NSW in Real-time ...................................................................... 12
Network Real-time Solutions ................................................................................ 12
Mount Points ............................................................................................................. 12
Other Features of CORSnet-NSW Real-time services.................................... 13
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Glossary of Terms
Term
CMRp
CORS
CORSnetNSW
DGNSS
GNSS
DFSI
MAC
Machine
Guidance
NRTK
NTRIP
RINEX
RTCM
RTK
SydNET
VRS
Definition
Compact Measurement Record plus - A format for real-time data
streaming, commonly used in agricultural and construction
applications.
Continuously Operating Reference Station - An installation that is
precisely located and continuously observing GNSS data. Arrays of
CORS are often linked together as part of a network to deliver
precise positioning solutions over large areas.
The CORS network infrastructure available in NSW from 1 July
2009.
Differential GNSS - A basic method of processing GNSS data to
achieve sub-metre level accuracies (often referred to as DGPS).
Global Navigation Satellite System - A global network of satellites
producing navigation signals for positioning and navigation
applications on earth.
Department of Finance, Services and Innovation - The NSW
Government Agency responsible for delivering CORS to NSW.
Master Auxiliary Concept - A method of NRTK which provides
CORS data with correction parameters generated from nearby
CORS in order to optimise the solution for a specified location.
A system which utilises positioning information to guide or autosteer machinery along a specified path.
Network RTK - An enhancement of RTK which utilises data from
multiple CORS to provide a uniform level of accuracy across the
network.
Networked Transport of RTCM via Internet Protocol - A method for
streaming RTCM messages over the internet.
Receiver Independent Exchange - An international standard for the
storage of GNSS data.
The Radio Technical Commission for Maritime Services - An
international standard for real-time data streaming of GNSS data.
Real Time Kinematic - A sophisticated method of processing GNSS
data to achieve centimetre level accuracies.
The CORS system offered in NSW prior to 1 July 2009 and as a
back-up system until 2 May 2011.
Virtual Reference Station - A method of NRTK which generates
virtual data from data collected at nearby CORS for a specified
location.
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Web Portal Instructions
The webpage for CORSnet-NSW is available at the following URL:
http://corsnet.nsw.gov.au
Logged Out Environment

CORS Map
The CORS Map shows a live update of station health for
every CORS in the CORSnet-NSW network. Sites in green
are healthy, while sites coloured yellow or red are currently
unhealthy or offline.
You can click on a CORS to display more information.

Login
To login to CORSnet-NSW you are required to enter your
organisation name, user name and password. When an
account is created for you, this information will be provided
through an automated email.

More Information
This link will take you to the CORSnet-NSW information
website to access CORS station details and other useful
information.
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Logged In Environment

Status Messages
Status messages are used to inform users of
important information about CORSnet-NSW. Three
levels of messages exist: Info, Warning and Alert.
These will be highlighted green, yellow and red
respectively to indicate the severity of the message.
Info messages will be used to inform users of
general news and tips for using CORSnet-NSW.
Warning messages will be used to inform users of
planned maintenance and any issues associated with
CORSnet-NSW. Alert messages will be used for
major issues and unplanned outages of service.
Users are advised to subscribe to the RSS feed to
ensure that they keep up to date with the latest
information available. This feed can be accessed
using various apps on smartphones in the field.
The CORSnet-NSW RSS feed is available at:
http://corsnet.nsw.gov.au/StatusMessageFeed.svc/?

Reference Data Shop
This is where you can access archived GNSS data as
RINEX files or alternatively in a number of other
formats.
The first time you access the Reference Data Shop
you will be asked to start a new order. After that you
will be given the options of choosing to View/submit
order, Add order items or Cancel order. You can
also view a list of orders not yet downloaded and
already downloaded orders.
When ordering data you are given the option of
ordering Continuously Operating Reference
Station (CORS) data or Virtual Reference Station
(VRS) data. CORS data is the data observed at the
CORS sites while VRS data is virtual data generated for a user specified
location.
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When selecting the Reference Stations for which you would like to download
data, you can either select one or many stations from the list or select them by
clicking on the map (not yet available).
Once your selection is complete, click Next: Time Selection >> and select the
date, start time, duration and interval. Please note that the time system used is
GPS time and not Australian Eastern Standard Time. You will need to
subtract ten hours from Australian Eastern Standard Time (or eleven hours for
Australian Eastern Summer Time) to determine the appropriate GPS time.
Once your Time Selection details are complete click Next: Add to order >>.
Here you can either select to add additional order items through a number of
options. Ensure you book the order under your primary login as real-time logins
do not have access to Reference Data Shop data.
Once your order is complete, click Next: Delivery Options >>. You have the
choice of downloading the data in a number of formats. These are RINEX 2.11,
RINEX 3.0, DAT, TGD, T01 and T02. While the RINEX formats should be
recognised by most software packages, the last four options are not international
standards but may be of use to some users.
When your delivery options selection is complete click Next: Generate Data >>.
A table indicating the Processing Status of the order will appear. You can close
this screen and the data generation will still continue. For large orders it may be
preferable to return at a later time to retrieve the data once this generation is
completed.
Once the data generation is complete, click on Next: Order Details >>. Here you
will see a summary of the order including the completeness of the data. Select an
order item and click on Details to see further information. Click on Remove to
delete an order item from the list. Click on Download to retrieve the data.
The data will be delivered in a compressed zip file. Within the zip file you will find
three RINEX files: the observation file, GPS navigation file and the GLONASS
navigation file. You will also find a text file which summarises the data ordered
including the completeness of the data.

My Account: Personal Data
This link allows you to update your personal details,
including address, email addresses, additional email
addresses and phone numbers. It is important that
this information is kept up to date to ensure you are
kept up to date with CORSnet-NSW related
information.
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
My Account: Change Password
This link allows you to change the password for your
primary login. It is advisable to regularly change your
password for security reasons.

My Account: Logins
Here you are able to view your primary login and
supplementary real-time logins. By clicking on one of
the logins you are to change its password. It is
advisable to regularly change your password for
security reasons.

My Account: Sessions
This link allows you to view your CORSnet-NSW
usage history over varying periods of time. Usage
history is summarised in terms of total organisation
usage, total login usage and total resource usage
(e.g. RINEX or real-time).
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
Active Subscriptions
Click on this link to view your current valid
subscriptions. Click on Details to view further
information.

Logout
This link will take you back to the logged out
environment home page. Click on Logout once you
have completed accessing CORSnet-NSW data and
information.
Using Virtual Reference Station (VRS) RINEX
Tips for users:
 Use ellipsoidal height. Convert from the Australian Height Datum (AHD71)
using AusGeoid09 here.
 Data available for 28 days.
 Orders take longer to generate than standard CORS RINEX.
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Recommended coverage is within the area for Network RTK published on the
CORSnet-NSW coverage map. The latest map is available from
spatialservices.finance.nsw.gov.au/corsnet-nsw in network information.
Achievable accuracy from VRS RINEX is comparable with CORS RINEX files.
Users are advised to test VRS RINEX to determine whether it is appropriate for
their application.
Absolute Antenna Models from the International GNSS Service (IGS) should be
used for VRS RINEX and all other data used in post-processing. The nominated
physical antenna in the VRS RINEX file is generally that of the closest CORS.
This must be correctly set in your post-processing software.
Site Transformations (or Localisations/Site Calibrations) are still required. Users
should always connect to local survey control to determine the offset from the
Survey Control Information Management System (SCIMS) coordinates.
Ongoing testing is being performed by DFSI Spatial Services to advise users on
the capabilities and limitations of VRS RINEX.
RSS Feed for CORSnet-NSW Status Messages
You can subscribe to status messages from CORSnet-NSW via RSS Feed. The
address of the feed is:
http://corsnet.nsw.gov.au/StatusMessageFeed.svc/?
There are several options available to access the feed.
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OPTION A – Microsoft Outlook
1. Right click on RSS Feeds on the left hand pane and select Add A New
RSS Feed.
2. Enter the address above and click Add.
3. Outlook will ask you to confirm if you want to add the feed. Click Yes.
OPTION B – Web Browser
1. Open the address above in your web browser (tested on IE 8):
2. Click Favourites and then Add to Favourites Bar (make sure the
Favourites Bar is displayed)
3. The link will appear in bold when new status messages are available
OPTION C – Download Program
1. Download RSS Reader available through the following link (alternate
programs available online):
http://www.rssreader.com
2. Install RSS Reader and subscribe to the feed address above.
OPTION D – Smart Phone App
1. Download an RSS feed reader application on your smart phone.
Subscribe to the feed address above.
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Real-time Instructions
Using CORSnet-NSW in Real-time
You can find your login details for real-time access on the CORSnet-NSW Web
Portal at My Account: Logins.
Real-time logins are usually in the format <organisation>/<login>. This login will
differ from the username used to log into the CORSnet-NSW Web Portal. The
number of real-time logins will depend on the number of subscriptions available.
All passwords are configurable within the CORSnet-NSW Web Portal.
In order to connect to CORSnet-NSW in real-time you will also need to enter the
following information into your equipment.
Ntripcaster Address: corsnet.nsw.gov.au
Port: 2101
Network Real-time Solutions
Network solutions are being introduced in NSW and the coverage area will be
extended as LPI continues to roll-out CORS across the state and tests the quality
of solutions in regional areas. For those who have not used a network solution
before, it will look and feel, in a practical sense, like a single base solution. Field
procedures should remain the same, particularly in relation to performing site
calibrations.
In areas tested to date, network solutions perform as well or better than single
base solutions. It is important to ensure that your equipment settings match the
particular mount point you intend to use.
The current network solution coverage is illustrated on the CORSnet-NSW map
(spatialservices.finance.nsw.gov.au/corsnet-nsw/network_information).
Mount Points
A mount point relates to a real-time data stream option. When connecting to
CORSnet-NSW in real-time, a mount point list is usually generated for a user to
select from. The following options are available:
Single Base mount point (eg CHIP-RTCM3 for Chippendale): This allows a user
to specify which CORS they would like to receive data from.
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Nearest Base mount point (eg nearest-RTCM3): This will automatically provide
data from the users closest CORS. An additional Nearest Base mount point is
available for legacy precision agriculture users only (nearest-RTCM2). Users are
advised, where possible, to continue to use the RTCM3 format.
VRS Network RTK mount point (eg VRS-RTCM3): This will provide a network
RTK data stream in Virtual Reference Station (VRS) format.
MAC Network RTK mount point (eg MAC-RTCM3): This will provide a network
RTK data stream in Master Auxiliary Concept (MAC) format.
Virtual Base DGPS mount point (eg DGPS-RTCM2): This will provide a submetre differential solution optimised for the user’s location.
CMRp mount points (eg nearest-CMRp, VRS-CMRp): Two additional mount
points, which use the CMR plus format, have been added to the mount point list.
These are intended for legacy equipment in industry groups where CMR plus has
been used as a quasi-standard format (such as precision agriculture). Users are
advised, where possible, to continue to use the RTCM3 format.
Other Features of CORSnet-NSW Real-time services
Please be advised that CORSnet-NSW adjusts real-time data so that all CORS
antennas are uniformly described as a null antenna (ADVNULLANTENNA). As such,
no base station antenna model needs to be applied to adjust CORS observations
from the Antenna Phase Centre to the Antenna Reference Point. Users will
still need to apply the appropriate absolute antenna model for their rover. All post
process RINEX files and post process files in other formats continue to hold raw
data to the Antenna Phase Centre in line with international standards.
Absolute antenna modelling, instead of relative antenna modelling, is used in
for CORSnet-NSW. These should be the absolute antenna models derived by
the International GNSS Service (IGS) and users are advised to contact their
local GNSS supplier for the required information. Users should also use absolute
antenna models when post processing for both the user and CORS antennas.
Any mix of absolute and relative antenna modelling will introduce significant
systematic errors.
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Contact Details
For more information or assistance please contact CORSnet-NSW Customer
Support at:
Phone:
Email:
Web Portal:
Web Site:
02 8258 7545
CORSnetCustomerSupport@lpi.nsw.gov.au
http://corsnet.nsw.gov.au
http://spatialservices.finance.nsw.gov.au/corsnet-nsw
Information provided in this document is intended as a guide only and its accuracy is not
guaranteed.
CORSnet-NSW Web Portal User Guide Version 2, July 2016
© DFSI Spatial Services July 2016
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