Just got the kinematic kits in the mail. Very disappointed work had to come first and I didn't get to play with it. I have been studying the archives here, and the manuals, and most of my questions have been answered (which by the way is why I like this board so much). Two questions remain though.

1. Do you have to hold the pole vertical as you are walking from point to point as shown on the video to maintain sv lock?

2. I noticed in Mr. Martin's 3 part instruction guide to initialization that to re-initialization on a previously kinematic observed point that nothing except the site id is required and that the software automatically recognizes that it is a re-init. What if I am doing boundary work and I am a cautious guy (which I am) and I observe all boundary control twice-does the software distinguish between repeat observations and re-inits., or do I need to manipulate the observation id?

Thanks for the responses.
Shawn P.C. Texas

Some responses, based on my practice:

1. Some times, if I put the pole/receiver down on the ground, takes some time to lose the locked sattelites and the kinematic sound alarm starts; but I recommend you to keep the pole nearly vertical as you can, because I think is less effort than a new re-initialization.
Maybe somebody from Ashtech helps us here and tell what kind of antenna is (microstrip?) and how it works in this situation (thanks!).

2. As I know, if you give for a kinematic point an ID used previously, the software takes it as a re-initialization. I advice you to use different IDs and in this way you have the possibility to decide later what are you doing with each pair of points (mean value, delete one, etc).
Hope this help,
Alec Sturza

Shawn,

Answers to your questions follow:

1. Your primary goal as you are moving from one point to another is to maintain lock on satellites. Keeping the pole vertical will help maintain satellite lock. If you tip the pole, it is possible that one or more satellites will no longer be visible by the antenna on top of the receiver.

2. Multiple observations with the same Site ID in a Stop&Go Kinematic data file will be combined during processing to produce one solution for the site. Multiple observations will improve the precision of a site except in the condition were the multiple observations are being performed for re-initalization. In this case, the first observation is used to position the site and subsequent observations are used to re-initialize using the position determined by the first observation. The software manages this automatically.

If your goal is to use multiple observations of the same site to produce a more precision solution for that site, use the same Site ID. The software will mark the vector to this site as Failed if the data collected through the multiple observations do not combine to produce a good solution. This serves as a quality check of the data collected for the site.

If your goal is to use multiple observations of the same site in order to produce two positions for the site that you can visually analyze for repeatability and consistency, then you will need to assign different Site IDs. By assigning different Site IDs to the multiple observations, the software is not aware that this is the same site. The software will output the position computed by each observation using the assigned Site ID.

To respond to Mr. Sturza's question about the antenna type, it is a microstrip. If you lay down the pole on the ground, the antenna will continue to see half the sky and track those satellites still visible.

Hope this helps.

Bill Martin
Ashtech Precision Products

Thank you for your response Mr.Martin.
Maybe you help me a little more: I have GPS measurement data from different GPS receivers/antennas and I’ve used for processing the value of 0.125m for the vertical phase center offset for Locus (in GeoGenius software). Could you tell me please if is correct ? I've seen that for other antenna types this value is not so an exactly one. Do I need some calibration constants ?
There is a technical code/identification for antenna/sensor/board for “Locus” ?

Thanks,
Alec Sturza

Alec,

0.125m is the vectical offset from the ARP to the top of the antenna patch. This is the best estimate for the location of the L1 phase center since the exact phase center location for the Locus has not been measured.

Bill Martin
Ashtech Precision Products