Shetland Attack Pony--Digital compass/clino for cave survey

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Shetland Attack Pony - Water proofing

Postby Marbry » Jun 15, 2008 2:10 am

Has anyone that's bought an SAP tried to fit it to a waterproof housing? It looks like the dimensions would easily fit one of the inexpensive housings designed for small digital cameras.

Most of the housing have a number of control buttons corresponding to on-camera controls, and a large window in the back to view the LCD screen. It seems you should be able to line up a housing button to control the SAP, and have it so that the readout is visible in the window.

This would allow it to be used for underwater surveying as well.

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Re: Shetland Attack Pony--Digital compass/clino for cave survey

Postby LWB » Jun 20, 2008 3:29 pm

The latest version of the SAP (the blue one not the black one) is sealed. However that is protection for mud and damp and not for underwater use. The size is slightly different than the black version (I think, I've only seen photos of the black one). It will just barely width wise fit in a Pelican 1030 (which is deeper than needed) or it fits in a Pelican 1040 with extra width remaining. See photos (assuming I attached them correctly).

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Re: Shetland Attack Pony--Digital compass/clino for cave survey

Postby wvcaveman » Sep 9, 2008 3:41 pm

Dear Fellow Surveyors,

Recently, there has been work done to evaluate the Shetland Attack Pony by myself, Rachel Bosch, David Riggs, Lynn Brucker, and Roger Brucker. For the past three months we've collected data on how well the Ponies agree with Suuntos, with the TruPulse 360, with a theodolite, with a TOPCON Total Station, and with each other. In addition, to evaluate cave worthiness, we've taken the Ponies on cave trips that included vertical, mud, swimming, long crawls, and even some nice strolls through Mammoth Cave trunk. ;-)

The initial goals of the work were to determine if digital survey instruments, like the Shetland Attack Pony and TruPulse 360, were up to the job of cave surveying and could survive the cave environment. As we began to learn more and more about the devices, later goals became design and implemention of ideal calibration courses for the Ponies because calibration is the most important step in their successful use.

Results from the first part of this work were presented at the 2008 NSS Convention in Lake City, FL, USA. The presentation is available in PDF format here ->
http://speleo.us/~abird/DigitalSurveyIn ... UG2008.pdf

In addition to evaluation of the instruments, an online questionnaire was conducted asking for feedback on others' use of digital survey tools. The raw data of that survey is available here -> http://speleo.us/~abird/DigitalSurvey_o ... ug2008.pdf

Because of our intention to use the Shetland Attack Ponies on surveys conducted within Cave Research Foundation (CRF) projects, they had to consistently demonstrate frontsight-backsight agreement of +/-1 degree. This level of accuracy is often achieved by experienced users of Suuntos. However, we found that the Ponies' ability to get this kind of accuracy was dependent on the quality of the calibration. Lynn has written several articles on this subject, which will be published in upcoming issues of the Compass & Tape.

In general, the findings are: 1. do not use an indoor calibration course, but instead build one outside (in a forest) or in a cave; 2. use of Suuntos for establishing the legs of a calibration course will likely place errors in the calibration data; and 3. it is beneficial to include several high-angle shots in the calibration data, however, establishing the high-angle shots must be done carefully, i.e. not with Suuntos.

Those who plan to establish a calibration course for the Shetland Attack Pony using Suuntos may wish to read Dale Andreatta's article in Compass & Tape (Vol. 17, No. 1, Issue 57, pg. 20) entitled, "An Analysis of Systematic and Randome Surveying Errors or Better Surveying through Mathematics," in which he presents the statistical case that individual instrument error is the largest source of error.


The abstracts of the presentation and Lynn's articles are included below.


Presentation: Survey Instruments, Digital or Manual? A field comparison of relative accuracy and practicality of usage.
2008 NSS Convention, Lake City, FL, USA
Aaron Bird, Rachel Bosch, David Riggs, and Lynn Brucker
http://speleo.us/~abird/DigitalSurveyIn ... UG2008.pdf
Abstract: This project served to investigate the use of digital hand-held devices compared against manual devices outside of traditional, professional surveying, in environments including caves. In recent years, the number and sophistication of hand-held surveying tools used in applications outside of professional surveying has increased. These tools have seen greatest use in construction and include laser range finders; digital inclinometers; and full-spectrum devices outputting distance, inclination, and azimuth. Specific devices include: Leica DISTO laser range finder, Shetland Attack Pony, TruPulse 200 range finder and inclinometer, and TruPulse 360 multi-function surveying tool. In the past, non-traditional surveying has been successfully conducted using survey tapes and hand-held manual survey instruments, such as Suuntos liquid-filled precision compasses and inclinometers. While very cost effective, manual instruments are subject to a number of errors. These include recording blunders, instrument variability, and instrument-reader variability. Furthermore, accuracy when using manual approaches decreases as shot distances increase. Results of this work show that the above can be largely eliminated by using digital surveying devices. The most significant finding may be that errors from instrument-reader variability are nonexistent for well-aligned shots due to the deterministic nature of making measurements with digital survey devices. There are, however, two significant downsides to digital survey tools: (1) their unreliability in harsh environments, and (2) their high cost in comparison to manual precision instruments. The key conclusions of this work are that digital survey tools applied outside of professional surveying are accurate, reliable in most environments, and relatively easy to use.


Article: Underground Calibration of the Shetland Attack Pony
To be published in future issue of Compass and Tape
by Lynn Brucker
Abstract: The Shetland Attack Pony is an electronic compass / clinometer designed for cave surveying. It is manufactured in the UK and is described as accurate to 1 degree1. It requires calibrating to produce accurate results. Calibration requires the establishment of a master station and 12 or more stations in the surrounding 360 degrees with elevation angles between +30 and -30 degrees inclination. This proves to be difficult outdoors, since stations at high vertical angles are difficult to establish. The manual1 suggests that indoor calibration should work well, if a master station can be established away from magnetic materials. After performing several indoor calibrations in a very large room, a check for magnetic interference revealed it may be a significant problem. So the best choice is to calibrate in a cave, where magnetic interference is less likely. This paper documents the process and the station locations of one cave calibration course so future Pony calibrations can be made at the same location. Information on the Shetland attack Pony can be found at: http://www.shetlandattackpony.co.uk.


Article: Accuracy and Precision of the Shetland Attack Pony
To be published in future issue of Compass and Tape
by Lynn Brucker
Abstract: The Shetland Attack Pony is an electronic compass/clinometer designed for cave surveying. It is manufactured in the UK and is described as accurate to 1 degree. It requires calibrating to produce accurate results, a process previously described, and during which some issues were noted. This paper serves to quantify the accuracy and precision of the Shetland Attack Pony and to investigate the source of a constant bias found during the process.. If this bias is recognized and corrected, the Pony appears to be capable of accuracy of plus or minus 0.5 degree. General information on the Shetland Attack Pony can be found at: http://www.shetlandattackpony.co.uk.


Article: Calibration Improvements for the Shetland Attack Pony
To be published in future issue of Compass and Tape
by Lynn Brucker
Abstract: The Shetland Attack Pony is an electronic compass/clinometer designed for cave surveying. It is manufactured in the UK and is described as accurate to 1 degree. It requires calibrating to produce accurate results, a process previously described. This paper documents three approaches to improving the calibration process. These are: 1) Using a fixture to stabilize the Pony during calibration data collection, 2) Realigning the laser in the Pony and 3) Processing two sets of data together. Then the instrument accuracy and precise is investigated based on the improvements made. Also described is experience with in-cave use and a 500 ft closed loop survey. General information on the Shetland attack Pony can be found at: http://www.shetlandattackpony.co.uk.
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Re: Shetland Attack Pony--Digital compass/clino for cave survey

Postby Laura » Apr 28, 2010 7:16 am

Hello to all,
the posts in this topic are relatively old but I don't know where else I could ask this question: does anybody knows how I could contact with Phil Underwood regarding the Pony? I tried to send messages to his email given in his site http://www.shetlandattackpony.co.uk/order.html for couple of times, but I got no answer :(
We would like to order one device, maybe he doesn't make them anymore?..

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Re: Shetland Attack Pony--Digital compass/clino for cave survey

Postby lleblanc » Apr 28, 2010 10:13 am

Try beardydoc@googlemail.com to reach Phil Underwood.
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