California Spring Adjustment - May 25, 2013

It is once again time for a broadcast coordinate update in California.  The new broadcast coordinates will be published on Saturday night May 25 at 10:00 PM ET and will ONLY effect California.

Why are we doing this adjustment?

California offers a unique set of challenges for RTK users.  A vast majority of the stations in California have significant positional velocities, which in short means they move.  On average the position of the stations in California move between 30 and 50 mm-a-year, and in some areas even more.  The average shift over the entire network for this adjustment was approximately 18mm.

Without our bi-annual adjustment of station coordinates in California, you would quickly see measurable coordinate differences as you moved throughout the state.  As the velocities of the stations vary from location to location, this can cause issues not only as you cross the plate boundary, but also in the area of influence of the plates themselves.  In California's case this means pretty much anywhere in the population centers of the state.

To get a better understanding of why we are doing this adjustment, please watch our original SmartNet North American Adjustment Webinar - LINK.

What does this adjustment mean to me?

In very simple terms it means the broadcast position of the base is going to move approx. 20 mm.  This is a relative small change that you may or may not realize in the field, however as more time passes between adjustments, the larger the immediate impact would be.  By adjusting twice a year we mitigate the shift from adjustment to adjustment.

What reference frame and epoch are we moving to?

We will still be in the NAD83(NA2011) reference frame to stay consistent with the NSRS and we are moving to a 2013.250 epoch.

How can I get back to my old coordinates?

We have made two (2) transformation sets available.

1. 2013.250 to 2012.750 epoch transformation, which will allow you to transform from the current epoch to the previous epoch.
2. 2013.250 to 2010.000 epoch transformation, which will allow you to transform from the current epoch to the common NSRS epoch.

Please click here to download the transformation information - LINK.

You can also perform your own local transformation, localization or calibration.  For more information about using this technique, please click here - LINK.

How do I see the current coordinates and superseded coordinates?

All current and superseded coordinates are available on the SmartNet User Portal.  You can find a station's information by using the "Site Information Search" tool, then you can see the current broadcast and processing coordinate, as well as find a button that will allow you to view all the superseded positions as well.

Once the new adjustment is published on May 25, we will also update the site database with the new NAD83(NA2011) Epoch 2013.250 coordinates.

For more information on using the "Site Information Search" tool, we encourage you to watch this short video - LINK.

How do I get support to better understand what this adjustment means?