After a lengthy trial of over a month, I think we now feel quite confident in the LOCUS static system. And so now we have decided that the Kinematic will be a great addition to our system. My questions are for kinematic users.

1. What accuracies have you found with say 6 sv's and pdop of 4 or less with say 30 sec's of occupation at 5 sec intervals?

2. Have you found that re-initializing on a previous point determined by kinematic observation weakens the strength of the following observed points?

3. I realize now that the question of capability under canopy is impossible to answer because everyone's idea of "canopy" is different. But by our own testing we have found that in what we would call medium foliage that a static observation came out as well as out of canopy (8 sv's pdop less than 3, 30 min obs.). But I would like any comments on canopy.

4. We have no clue what accuracies to expect but guessed that for topo shots (where .1' horz and vert are desired) the 30 sec obs. at 5 sec int. would do nicely. And for more stringent accuracies (.05' horz and .1' vert or better) were desired a 2 min obs at 5 sec int would do. Does this sound good?

5. How do you keep up with notes on points while doing your measurements?

6. I remember in the training video provided by Sokkia that the guy doing his static work kept the pole near perfectly vertical. While I understand that you have to stay mindful of your lock is this really necessary?

Thanks for all input. This stuff sure is slick. By the way-why is it that so many of you wish for LOCUS processor to give ground measurements? It seems fairly easy to do conversions from grid to ground in almost any COGO package.

Looking forward to my
coming education,
Shawn P.C. Texas

I think on yout question #6 you mean "the guy doing kniematic work"...while he's moving from one point to the other. Right?

your not yout...must be the genes...

1&4 We are using Locus Kinematic for a half an year, usually with 16-20 seconds site ocupation at 4 s interval and the maximum length of vectors about 3 km. Excepts fail vectors (under 1% of total kinematic), the positional accuracy is between 0.005-0.03 m.
2. Re-initialization on a previous point (P0) determined by kinematic measurement involve for next points (PI) an additional error. In a simplistic way, if the error of Po is Mo, and the error of measurement i is Mi, then the total error for Pi = sqrt(sqr(Mo)+sqr(Mi)).
3. Under any type of canopy you have almost no chance with kinematic, due to frequently loosen of locked sat.

Hope this help,
Alec Sturza

5) I use a digital recorder for note-taking, but usually don’t need to refer to it very much as it is remarkably easy to recall 95% of the descripions recorded once they are plotted into CAD. At least, this is true for most projects where there is a lot of redundancy in the descriptions.

3) Sub-canopy results vary so widely as to seem almost random. But, I have noticed that as the number of small blocking objects (branches and leaves) increases the probably of poor results increases as well if the objects are more or less evenly distributed. An example would be 50% admitted light in an oak-woodland forest. Given the same number of blocking objects, uneven object distribution seems to produce better results. At times, solutions generated are correct under either condition; at other times, not, even though the pdops may be suitable and the satellites are not clustered, and even though the processor may indicate strong statistical confidence in the results.

It would be interesting to find out if the solution generator uses an ordinary trigonometric method with some of the satellite data or an iterative convergence algorithm with all of the satellite data. Knowing this might be helpful when theorizing about which canopy arrangement produces the best results.