board disappointment
Posted By cliff wagner on 7/25/2001 at 9:16 PM

Jeez guys I posted on monday and have had no responses to my question. Iam trying to get an idea about the accuracy of the GG24 with glonass real time system. I bought a used system and thus far I am disappointed in the autonomous positioning...I would think that I could get a positional accuracy in the meter range with enough occupation time at the base...I really would like to here from users or ashtech about what accuracy I could expect from this system...any advice would be appreciated


Re: board disappointment
Posted By William Martin on 7/26/2001 at 9:20 AM

Cliff,

Sorry for the late response.

Unfortunately, autonomous positioning at the meter-level is not possible with the GG24, or any other GPS system for that matter. Yes, if you sit long enough on a point, you may get a meter-level position. But, you cannot depend on this to occur every time. The next time, you may find that your position is only good to 5 meters or more. There was a time when GPS+GLONASS receivers had advantages over GPS only receivers in autonomous positioning. This was when Selective Availability was enabled. Since it has been disabled, the GG24 no longer has this advantage. The GG24 will provide the same autonomous positioning accuracy as a GPS-only system now with SA disabled. There was a couple of posts on the general message board a while back showing the current expected accuracy of autonomous positioning with SA disabled.

Sorry I don't have better news.

Bill Martin
Ashtech Precision Products


Re: board disappointment
Posted By Rod Johnson on 7/26/2001 at 11:38 AM

Cliff,

This board is great. I love to see what people are saying. It is NOT however, an official Ashtech web site.

While the site is a good resource, you are welcome to make Ashtech customer support (1.800.229.2400) another resource for your questions. You might get the answers about the receiver "from the horse's mouth", and the answer may come quicker.

Best Regards,

Rod Johnson
Thales Navigation
Ashtech Product Marketing


Re: board disappointment
Posted By Bill Cottrell on 7/31/2001 at 3:28 PM

Cliff
Please see my response to your posting re "Autonomous Positioning" on the general discussion board.

Also you may want to download the "Evaluate" software from the Ashtech website. Among other things, it has an analysis feature that will enable you to perform an autonomous position averaging on a static antenna and will compute error statistics for the position solution.
The software is free.

Rod Johnson makes a good point, you can usually get rapid response to questions like this by contacting Ashtech tech support directly. Along with the phone number Rod posted above, you can also email to [support@ashtech.com]

BC