Float Solution

How long is the base line, Aryo?

At least 30-40 km, with the long observation between 1 hour - 1 h 15m

When you say dense, do you mean there is a lot of overhead obstructions, such as trees or buildings? If there is, you probably can't get a fixed solution.

Increase your occupation time to 4 hours and reprocess.

Thanks for your sharing. yes, my working area are mountain and forest. Maybe it will work if i try increase my occupation time

On some occupation sites under cover I have obtained better results by raising my antenna height by adding more sections to the pole.

I've had height as much as 6 meters to get better horizon to work in.

If you are under dense foliage, you will need to set control in the open with GPS and run conventional in to the site. Alternatively, you could clear the site around your GPS if that would be possible.

There are many things that can go wrong.

I'd say that your problems, (like others have said) are the obstructions, and the length of baselines.

The obstructions are going to hurt you more, but long baselines, are not going to help. It sounds like this is your first foray into Post processed GPS.

My advice is: Reduce those baselines. All this means is to set control in fields, with no obstructions, and work off of those. I think the longest observation I did was 36 hrs. This was for a short baseline. To overcome obstructions. Once you get 12+ hrs of observation in your computer, you can LOOK at the data, block out part of the time, compute it. Then, block out another part of the time, and compute it.

I know such an activity is not generally cost effective, in the "get er done" work world. BUT

It is very effective in educating yourself, as to what happens with obstructions.

And, that is what you are after. You want to KNOW what you are doing. And this will help.

N

While the problems of multipath and obstructions to the signal seem the likely cause, I suggest submitting your data to one of the many free on-line GPS observation processors. See the links at: http://geodesyattamucc.pbworks.com/w/page/13931102/FrontPage#Lab5AutomatedGPSProcessingToolsbeyondOPUSdue27March2013nbsp

I would also recommend running the teqc program on your data using the quality checking option. The program, teqc, will graphically depict which satellites are being tracked and show cycle slips and loss of lock. It will also show the magnitude of multipath. Your software may already include a similar feature. The program is available for free download from UNAVCO. There should be a link to the software on the same web page.

The automated processors are very robust. They can be used to verify your processing results.

Fixed integer solutions are always best when the integers are fixed to their correct values; fixing them to the wrong values is worse than a float solution.

Hope this helps,

DMM

On some occupation sites under cover I have obtained better results by raising my antenna height by adding more sections to the pole.

--

Yes, I have raised my antenna height to 4.6 m with stick pole and increasing my occupation long time. It is better than before. thank you