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Last modified by robert on 2024/05/17 16:52
From version 8.1
edited by Sima Mousavi
on 2024/01/29 14:42
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To version 6.3
edited by Sima Mousavi
on 2024/01/29 13:13
Change comment: There is no comment for this version

Summary

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1 -integrated Distributed Acoustic Sensing (iDAS)
1 +Distributed Acoustic Sensing (DAS)
Content
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1 -= **What is iDAS?** =
2 -
3 -**iDAS** stands for **Integrated Distributed Acoustic Sensing**. This advanced system utilizes the principle of Rayleigh backscattering in optical fibers to measure strain rates along the fiber's length. It's a cutting-edge technology predominantly used in fields like geophysics, where it's crucial for monitoring seismic activities, as well as in industrial applications like pipeline monitoring and security systems.
4 -
5 -=== **Safety first!** ===
6 -
7 -=== ===
8 -
9 -(% class="box warningmessage" %)
10 -The iDAS uses a Class 1 laser, which is generally considered safe for most applications. However, direct exposure to the eye should be avoided to prevent any risk of eye injury.
11 -\\Cables and fibers may create tripping hazards. Ensure that the routing of cables is done in a way that minimizes the risk of accidents.
12 -
13 -----
14 -
15 -=== **System Components** ===
16 -
17 -**Interrogator Unit**
18 -
19 -* The heart of the iDAS system, this unit contains the laser source, a detector for capturing backscattered light, and electronics to process this signal. It's critical for generating and interpreting the data collected by the optical fiber.
20 -
21 -**Optical Fiber**
22 -
23 -* This component acts as a long, distributed sensor. Strain rates along this fiber are what the iDAS system measures and analyzes.
24 -
25 -**Data Acquisition Software**
26 -
27 -* This software interfaces with the interrogator unit, allowing users to configure acquisition parameters, initiate data capture, and process the collected data.
28 -
29 -= =
30 -
31 -= =
32 -
33 33  = **DAS Data Collection System** =
34 34  
35 35  ==== **1. Interrogator Unit** ====
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61 61  * **Physical Location Determination:** The physical locations of these channels are ascertainable through methods like tap tests and GPS tracking.
62 62  * **Metadata for Channels:** Each channel or group of channels has its own metadata block, detailing specifics like location and properties.
63 63  
64 -[[image:1706489800616-982.png]]
32 +=== ===
65 65  
66 -
67 -
68 -[[image:1706488566274-805.png]]
69 -
70 70  ----
71 71  
72 -= **DAS Metadata Schema** =
73 -
74 -==== **1. Interrogator** ====
75 -
76 -* **Required:** Interrogator ID, manufacturer, model.
77 -* **Optional:** Serial number, firmware version.
78 -
79 -==== **2. Acquisition Parameters** ====
80 -
81 -* **Required:** Interrogator ID, acquisition ID, unit of measure, acquisition start and end time, acquisition sample rate, gauge length, number of channels, spatial sampling interval.
82 -* **Optional:** Pulse rate, pulse width.
83 -
84 -==== **3. Overview** ====
85 -
86 -* **Required:** Network code, location, start date, end date, point of contact.
87 -* **Optional:** Digital Object Identifier (DOI), purpose of data collection, funding agency.
88 -
89 -==== **4. Cable Information** ====
90 -
91 -* **Required:** Cable ID, cable bounding box.
92 -* **Optional:** Cable owner, cable installation date, cable characteristics.
93 -
94 -==== **5. Fiber Information ('Native format')** ====
95 -
96 -* **Required:** Cable ID, fiber ID, fiber geometry, fiber mode, fiber refraction index.
97 -* **Optional:** Fiber optical length, fiber start and end location, fiber one-way attenuation, fiber winding angle.
98 -
99 -==== **6. Channel Group** ====
100 -
101 -* **Required:** Interrogator ID, acquisition ID, channel group ID, cable ID, fiber ID, coordinate generation date.
102 -* **Optional:** Location method, coordinate reference frame, first/last usable channel ID, uncertainty of various coordinates (x, y, latitude, longitude, elevation, depth, strike, dip).
103 -
104 -==== **7. Channel** ====
105 -
106 -* **Required:** Channel group ID, channel ID, coordinates (x, y, latitude, longitude).
107 -* **Optional:** Elevation above sea level, depth below surface, distance along fiber, strike, dip.
108 -
109 -----
110 -
111 111  === ===
112 112  
113 113  = **Pre-processing Steps for DAS Data (2.5 months, 90 TB)** =
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247 +[[image:1706489800616-982.png]]
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328 328  [[Caption>>image:1706488806394-168.png]]
329 329  
330 330