Due to changes made in the default configuration of the Trimble NetR9 receivers that makeup the NSACS network in Nova Scotia, there was an unintended height offset injected into the data streams that all third-party networks receiving data from NSACS station were effected by. This change was unknown to NSACS and unknown to SmartNet until a recent investigation uncovered the issue.
The height offset was approximately 0.20 meters, which corresponds with the difference between the phase center broadcast of the antenna (which is what we and NSACS were expecting) and the ARP (which was what was actually being broadcast, i.e. ADVNULLANTENNA). This change happened due to a firmware upgrade and was not intended by either NSACS or SmartNet. We have contacted Trimble and received the following response:
Directly from Trimble;
"With the release of the NetR9 firmware v4.93, the antenna correction is by default applied to RTCMv3 streams to
normalize the corrections and send a null antenna. This was done to assist third party equipment which may not contain updated antenna types. If a user would still like to receive the IGS antenna name within the RTCMv3 stream, then they need to uncheck this option on the receiver. "
Corrective measures have been taken to confirm what we are receiving and what is being broadcast matches our expectations, as well as NSACS expectations and published information. Other measures will also be taken to assure that this type of issue does not surface again in the future.
Additionally, we are investigating all other data streams that may be effected by this issue in other areas of SmartNet as well.