Reflectorless Accuracy determination

RSAsurv, post: 389942, member: 10950 wrote: Hi all,

A collegue and fellow student of mine has taken the module "resesrch metholody" and requires him to pick a topic and do a research proposal on said topic.

He chose "reflectorless accuracy on different surfaces,different angles of incidence,different colour,different temperature and shade/unshaded" as a topic.

I recommended he be more spesfic example
" trimble s5 reflectorless measurements accuracy on steel vs traditional prism edm". This could include different colours,angles,temp,shade/unshaded. Going to broad complicates things at this stage.

Does this sound reasonable? Are than any other factors that he could consider? I know Kent and Bill should have some advise in regard to how to calc the MRMS,bubble errors etc so this will be appreciated.

Thanks

Dirk

Interesting. Others will have ideas about specific setups to test, but I'd say don't compare reflectorless to prisms...any results would likely be a combination of systematic as well as random errors.Prisms have their own errors you'd then have to weed out.

He's on the right track to compare different surfaces, different angles etc. (reduce the number of options to test if necessary), but do it on a test range of known distance and compare the reflectorless results to "reality", i.e. the known distance between the gun and the target.

To eliminate most prisms error I suggested be use an SMR that fits into 5/8" flange hole. Then survey from concrete beacon without removing tribrach for as long as possible.

Lets say he does 500 2D and 2R measurements then reduces that to 2mm RMS and the dist is 100,000m. How do you then replace the prism with a steel or concrete something without changing the centring of the "prism"? So how does he replace prisms with concrete?

Thanks

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Below is an extract from a previous article that also did some other research. Interesting about the battery power influence and the sun influence on the level

Based on the analysis of the theoretical and experimental study, the following conclusions can be summarized:

(1)
The appearance of precise digital level will make the process of leveling easier and automatic and will save the observation time and also more accurate by 10‰ÛÒ15% than optical leveling.
(2)
The influence of the sun position on the errors of leveling observations resulted from digital leveling is significant. So during the high-precision leveling by using digital levels, for example monitoring the structural deformation, it is important to take into consideration the position of the sun above the horizon, because the error of the digital level observations when the telescope is placed in the direction of the sun increases the observations errors at an average of 30‰ÛÒ35%.
(3)
Total station Leica TCR 405 Power can perform reflectorless slope distances on different surfaces made from different materials and painted with different colors. The accuracy of slope distances and angles measurements by this instrument is less than the specified value of accuracy in its specifications.
(4)
It is found that the battery capacity of electronic surveying instruments has a clear effect on the measurements because practical tests proved that decrease in battery capacity increases the measurements errors.
(5)
Accuracy of reflectorless total station observations depends mainly on the power of the signal, which is reflected from the reflecting surface. The intensity of the returning signal depends on the distance from total station, the angle of inclination of the reflecting surface, the angle of incidence, and reflectivity of reflecting surfaces which have different color and made from various materials. It is found that the white reflecting surface has a stronger reflectivity than any other surface. Increasing the angle of inclination of reflecting surfaces also provides an increase in measurement errors.

http://www.sciencedirect.com/science/article/pii/S1110016812000075

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A factor I did not see mentioned could be weather conditions. High humidity, fog type conditions, dust (working on a construction site) or ideal light working indoors.

Hi Brian,

Those are good factors to look into,however our geographic location would make natural fog or high/low humidity an issue,we just dont have much of that around here. Fog only in winter and only maybe once or twice a year. Humidity varies at between 45% to maybe 60% year round.

Dust is a smart one. Be good to remember that. Would internal/external not bee similar to shaded/unshaded?

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You would be surprised how good the reflectorless is. Almost all my reflectorless shots are less than 200 feet and at that distance it's impressive. My new s7 can aim horrid angles at corners and it's dead on. I test it all the time and it's insane.

RSAsurv, post: 389953, member: 10950 wrote: Hi Brian,

Those are good factors to look into,however our geographic location would make natural fog or high/low humidity an issue,we just dont have much of that around here. Fog only in winter and only maybe once or twice a year. Humidity varies at between 45% to maybe 60% year round.

Dust is a smart one. Be good to remember that. Would internal/external not bee similar to shaded/unshaded?

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I guess inside and out would be similar to shaded and not. Is the inside of a low lit building the same as a tree canopied environment? Depends how deep you want to dig I guess?