C9 24Q4037 Question and Answer 001.pdf
PDF 103 KB Posted
- Attached to
- Crane Rail Survey Federal contract opportunity
- Solicitation number
- N4523A24Q4037
About this file
This document is Question and Answer #001 regarding a federal contract opportunity for a Crane Rail Survey. The contractor inquired about performing a manual survey by walking the rail instead of using a robotic survey, citing concerns about the accuracy of 360-degree prisms on robotic carriages. The government responded that they are amenable to the contractor's proposed manual survey method.
The related federal contract opportunity is for the Regional Maintenance Center at Puget Sound Naval Shipyard and Intermediate Maintenance Facility (PSNS & IMF) to award a Firm-Fixed-Price contract for crane rail surveys. The anticipated period of performance is 10Jun2024 through 19Aug2024, and the contract will be awarded to a responsible small business contractor on a lowest price, technically acceptable basis in May 2024.
View the file
Other files for this federal contract opportunity
| File | Type | Posted |
|---|---|---|
| C9 24Q4037 Question and Answer 002.pdf | ||
| C9 24Q4037 Question and Answer 001.docx | DOCX document | |
| C8.2 24Q4037 Attachment 2 Wage Determination - Kitsap County.pdf | ||
| C8.1 24Q4037 Attachment 1 Contractor Badging and Access Requirements.docx | DOCX document | |
| C8.0 24Q4037 RFQ for Crane Rail Survey.pdf | ||
| C8.3 24Q4037 Attachment 3 Corporate Experience Data Sheet.docx | DOCX document |
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Text version
Question and Answer #001
Question:
It looks like you are requiring a robotic survey. Is it possible for us to walk the rail instead to avoid using man lifts? This is what we did for the survey we performed at Bldg 491. Any robotic survey will still require a total station at the floor level and multiple setups which may not meet your goal to avoid shop disruption.
Also, we have been tracking the issue of using 360deg prisms on robotic carriages and have found that they do not meet the accuracy requirements for a crane rail survey. As you can see in the abstract below, just the 360deg prism itself can introduce several mm of error into the measurement. An error of 1.5mm is ~ 1/16” which is enough to completely throw off a rail survey. We only use circular prisms with our own fixture to center the prism on the head of the rail. Please reconsider this robotic requirement.
Impact of Prism Type and Prism Orientation on the Accuracy of Automated Total Station
Measurements
Investigations performed several years ago showed that for high-accurate surveying tasks it is indispensable to use circular prisms instead of 360° prisms. The deviations depending on the orientation of the 360° prism can rise up to several millimeters, which was demonstrated in several tests at different research institutions, see e.g. Favre & Hennes (1999), Stempfhuber & Maurer (2001), Ingensand (2001) or Krickel (2004). Mao & Nindl (2009) give an overview of possible measurement errors when using different prisms types and describe the sources of these errors. Relevant factors are the prism construction
(glass quality, geometry, coatings), the prism alignment with respect to the line of sight of an instrument and the used electronic distance measurement (EDM) unit.
Answer:
We are ok with the method that this contractor would like to conduct the rails surveys.
File details come from the government source that posted it. Updated .