Backwards approach to kinematic solution?
Posted By Dave Huff on 7/23/2001 at 6:27 PM

Ok, I was thinking today, which on occasion as of late may be a rare condition.
Now, lets suppose I had this big static network, and I wanted to set a few new sites and tie them to the network. Without the usual static observation on the new points, I am thinking this:

Set up "base" Locus on new point. Take second receiver around to known points in the network and perform an initialization on these, followed by a kinematic observation. I could drive right up to most of them, jump out and in just a few minutes have them done.

Now, the question is how will the Locus Processor handles this in giving me values for the "new" point where the "base" is? Think this would be viable? Any takers?




Re: Backwards approach to kinematic solution?
Posted By Nearly Normal PLS on 7/24/2001 at 5:02 AM

I would not use locus processor at all to tie them together.

Just process as a separate job, and rotate into the first using cogo. Rotation should be nearly zero, just a translation.




Re: Backwards approach to kinematic solution?
Posted By William Martin on 7/24/2001 at 11:16 AM

Dave,

Interesting question. Let's see if I can answer it in a way that makes sense.

The approach you propose requires an examination of two separate aspects of the process. The first aspect is the processing of the new kinematic data, the second is the integration of the new points from the kinematic data into the existing network.

Let's start with the processing. We need to look at the initialization. In your example, the kinematic base point is new, i.e. does not have a known position. Therefore, you cannot perform a known-point initialization using a known rover point since a known-point initialization requires a known base and rover position allowing for initialization with a 10+- second observation. Your remaining options are to perform a bar-point initialization at the base (base does not need to be know for a bar-point initialization) or perform a static-survey initialization at the rover. The fact that he rover position is known does not help in this initialization. If you perform a bar-point initialization, be sure to observe at least one of the known points from your static network during the kinematic survey. This will provide the link to the known network. Regardless of the initialization mode used, observing more than 1 known point from the static network during your kinematic survey will help with part 2 of our discussion, ie link to the existing network.

When processing your kinematic data, enter the observed known points of your static network into the Control Sites tab and hold them fixed for processing. This should be done regardless of the initialization method used. Known points peppered throughout your kinematic survey will serve as both a check of the survey and an initialization if loss-of-lock occurs without your knowledge.

Once you have successfully processed your kinematic data, we can proceed to part two of our discussion, integration into the existing network. This will be done simply by performing an adjustment of the new kinematic vectors, holding fixed all of the known points observed as part of the kinematic survey. By holding fixed the known points from the static network, the base point and all new kinematic points will be assigned positions based on these known points. The result in the integration of these new points into your existing network.

Hope this helps.

Bill Martin
Ashtech Precision Products



Re: Backwards approach to kinematic solution?
Posted By Dave Huff on 7/25/2001 at 12:46 AM

Thanks Bill,

I was specifically interested in obtaining a "new" point for elevation purposes; where the ideal scenario would be to set up the "base" receiver so to speak on an unknown point, and then get in the car and drive to the knowns, with a short kinematic observation on those. Loss of lock would be a guarantee between the known points.
I've been putting together this big static network by importing processed vectors of individual jobs, using the "one file per project" method. So far so good, just curious.
Hope you are doing well and Thanks again,
Dave