Network-RTK Testing & SydNET

Author: Nicolas James Tucker

Supervisor: Dr. Craig Roberts

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Continuously Operating Reference Stations (CORS) networks have experienced a significant growth in numbers over the previous decade.  This has been due primarily to their many applications and ability to overcome issues in real-time positioning.  Sydnet is one such CORS network that operates throughout the Sydney basin (Refer to Figure 2-1).  The development of CORS networks has also enabled the implementation and further advance in Network-RTK techniques.


Figure 2-1: SydNET station locations over the Sydney Basin & regional areas (Yan, 2004).


Sydnet is able to provide its users with consistent centimetre level horizontal accuracies (Roberts et al, 2007).  The services it provides to users include (Rizos et al 2004):

         Post-processed RINEX files

         Single base RTK


         Real-time code-based DGNSS corrections

These corrections are published on the internet, while the real-time data can be accessed via a mobile phone connection in the field.


An integral part of this project is the area in which the observations will take place.  A constraint, however, is that the SNAPper research software is only compatible with Ashtech receivers (At the time of writing).  The three stations selected from Sydnet include Villawood, Mulgrave and Springwood (VLWD, MGRV & SPWD on Figure 2-1), which all use Ashtech receivers (at time of writing June 2008).  Within this area of operations, the triangle formed by the three stations, high order marks, class C and above in the horizontal, have been searched for on SCIMS in 5km spacings from the Villawood station in an approximate bisecting line (Refer to Figure 2-2 below). 


Figure 2 2 : Area of Operations and 5km Markings


The marks will be observed at the same time with both softwares.  This will be achieved through the use of a splitter, where one antenna is connected to two Leica 1200 units (Refer to Figure 2.2 below).  In doing so, a seamless comparison of the two softwares can occur, as both use a VRS solution.


Figure 2 3 : The SNAPper Field Testing Splitter concept that will be used (Yong, 2008).