ok, i will apologize in advance for starting this topic, but it seems relevant to recent dialog. we are static users now, and will be moving to RT in the near future. having said that, i want to clarify my future expectations/plans.
rambling thoughts and questions:
1 do you use RT for control in ALL of your projects?
2 when you record a point, isn't the norm to get the coord from the computed vector, (and with the vector is the VCV matrix)? now the VCV matrix is the indicator of three dimensional quality of that measurement, right?
3 if you do use RT for control, how often do you record your data? do you just get the measurement and keep getting up? how many record your data, and filter later, for improved quality (similar to static)?
4 how many record your data, just to know you have it in the event of needing to investigate future problems/issues?
i want to make sure our data and published coordinates are good, in future RT work.
possible scenario for the future; there is a disparity with a coord triplet or several of them. we get the call, but can't investigate any raw data, BECAUSE WE NEVER LOGGED IT. now we got to hustle out to the project and redo the work. my expectation is the odds of this is possible. since we are local gov't we will be making coord's of markers published for others to use. many of our retracement projects are big, many markers, etc. i want to make sure we start on the proper foot.
1 do you use RT for control in ALL of your projects? Network to bring control into the project 95%. Base rover to spread it around 95%. Lots of stakeout or overhead obstructions - use total station. Lots of topo detail - use scan station. Usually during the course of the project the total station or scan station work will check the less dense RT control .
2 when you record a point, isn't the norm to get the coord from the computed vector, The phase center rover NEZ position is calculated from the known NEZ position of the phase center of the base or reference station using the corrected observed delta differences in N, E and Up between the two.
3 if you do use RT for control, how often do you record your data? 15 second observations every 2 hours for 5 sessions. do you just get the measurement and keep getting up? Not sure what the question is. how many record your data, and filter later, for improved quality (similar to static)? Raw data saved is time, observation quality data (RMS)and deltas between phase centers of rover and base. If the raw data has any red flags such as a VDOP of over 2 for the vertical delta we might consider an additional observation. Also if the deltas of one observation are unreasonably different that the others it may be thrown out and re observed.
4 how many record your data, 100%
Note to self: Don't use RT for control until you are comfortable that your process results in the same quality you would get through other means. i.e. the RT checks leveling and total station enough that you have confidence that your process works. Mistakes can be made using any process. If you develop a process that produces repeatable results, RT works as good as an other measuring method for most projects. IMO
>
> 3 if you do use RT for control, how often do you record your data? 15 second observations every 2 hours for 5 sessions. >
ok, so it sounds like you prefer static for control, then. five sessions, ten hours total, is a good amount of data. thanks for your response.
Moe
No
5- 15 second RT sessions two hours apart. 1 minute and 15 seconds total data.
copy that. sounds good
>
> 3 if you do use RT for control, how often do you record your data? 15 second observations every 2 hours for 5 sessions. do you just get the measurement and keep getting up? Not sure what the question is. how many record your data, and filter later, for improved quality (similar to static)? Raw data saved is time, observation quality data (RMS)and deltas between phase centers of rover and base. If the raw data has any red flags such as a VDOP of over 2 for the vertical delta we might consider an additional observation. Also if the deltas of one observation are unreasonably different that the others it may be thrown out and re observed.
wait a minute,now that i think of it, time, RMS, and phase center deltas are not raw data. these are supporting criteria for the measurement only. isn't the raw data the observable (aka the range measurements to SV's) ??? if the above is the case, you have not much to recompute in the future, should there be a doubt in a measurement. right?
Good catch! Unfortunately the data about the observation is all that is available from most RT manufacturers.
The title of the thread contains the premise that you have to defend RT observations. I submit that you might have to defend the results of the survey at some point, not the technical procedure you followed to obtain those results.