The new Mobile Mapper upgrade sounds useful and I am looking forward to hearing reports from the field. I downloaded the FAQS from the ftp site but still have questions.

I assume a person could set up a Promark on a known location and it could also serve as a base for post processing against the MM data. I also assume you could use Rinex data from a CORS site or another receiver as long as the epochs matched and you had suitable control and short baselines.

I also assume that you can look at both the real time data and the post processed data for the same project to see how they compare.

I gather that MM post processed elevation numbers are not very good for short occupations. If you set up the MM for occupations of a minute or so does the post processed accuracy reliably come up to submeter for horizontal and vertical and does the software provide methods to determine the reliability of the post processed solution?

Finally if the base unit was set to record data at 10 seconds and the MM was collecting one second data could a person still reliably post process longer (say one minute) static occupations from the MM?

Maybe some of these questions were answered in the FAQ so I apologize if any of this is redundant.

Thanks

LAJ

Check out an application note you can download from the ftp server at

ftp://ftp.thalesnavigation.com

The file that will help answer your questions is named

MM_Accuracy_App_Note


Some answers from Linda:
>I assume a person could set up a Promark on a known location and it could also serve as a base for post processing against the MM data. I also assume you could use Rinex data from a CORS site or another receiver as long as the epochs matched and you had suitable control and short baselines.

Yes, this is correct. You could also use a Locus, Reliance SCA, or any of our L1/L2 receivers. It is preferable, but not mandatory that recording intervals match on both receivers.

>I also assume that you can look at both the real time data and the post processed data for the same project to see how they compare.

You can certainly look at the Map View display and see the improvement in the lines are areas after the data is post-process, but no, there is no way to overlay both results at the same time.

A comment from Phil: You could export the file before and after processing and compare the two results in your mapping software or a spreadsheet.

>I gather that MM post processed elevation numbers are not very good for short occupations. If you set up the MM for occupations of a minute or so does the post processed accuracy reliably come up to submeter for horizontal and vertical and does the software provide methods to determine the reliability of the post processed solution?

No, at this time, the software does not display any accuracies or precision values. The attached PDF documents our test results.

Note from Phil: The most reliable way to determine accuracy is to test a system or a measurement method against known values. The alternative method is to make redundant measurements.

>Finally if the base unit was set to record data at 10 seconds and the MM was collecting one second data could a person still reliably post process longer (say one minute) static occupations from the MM?

Yes, the software will automatically interpolate the intermediate epochs to match the Rover recording interval. Although this is a bit of drift between the 10-second epochs, the effect is negligible when the goal is sub-meter accuracy.

Modified By Phil Stevenson on 4/6/2004 at 2:03 PM