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Version 6.5 by Sima Mousavi on 2024/01/29 14:36
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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 (% class="box warningmessage" %)
9 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.
10 \\Cables and fibers may create tripping hazards. Ensure that the routing of cables is done in a way that minimizes the risk of accidents.
11
12 ----
13
14 = **DAS Data Collection System** =
15
16 ==== **1. Interrogator Unit** ====
17
18 * **Function:** The interrogator unit is the core component of a DAS system. It sends laser pulses through the optical fiber and measures the backscattered light.
19 * **Recording Information:** It records various settings such as the optical system configurations, spatial sampling rates, and the duration of data acquisition.
20 * **Multiple Interrogators:** More than one interrogator may be used in an experiment. Each unit should have a unique identifier and is described in its respective metadata block.
21
22 ==== **2. Surface Installation** ====
23
24 * **Cable Arrangement:** The optical fiber cable can be a single long continuous cable or multiple cables with connectors, used across different installation environments.
25 * **Cable Types:** Cables may vary in construction types based on the installation environment.
26 * **Geographical Metadata:** Parameters related to geographical location are specified for easy searchability in databases.
27
28 ==== **3. Fiber Optic Cable** ====
29
30 * **Cable Composition:** Several optical fibers may be enclosed within one cable.
31 * **Metadata Identification:** The metadata identifies each individual fiber used in the acquisition, including its intrinsic properties.
32
33 ==== **4. Installation Environments** ====
34
35 * **Shallow Burial:** The cable can be shallowly buried.
36 * **In-Conduit Installation:** The cable can also be installed within a conduit.
37 * **Water Installation:** Suitable for underwater environments.
38
39 ==== **5. Channels** ====
40
41 * **Sensor Distribution:** Channels represent sensors distributed along the fiber array at fixed intervals.
42 * **Physical Location Determination:** The physical locations of these channels are ascertainable through methods like tap tests and GPS tracking.
43 * **Metadata for Channels:** Each channel or group of channels has its own metadata block, detailing specifics like location and properties.
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45
46 [[image:1706489800616-982.png]]
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48
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50 [[image:1706488566274-805.png]]
51
52 ----
53
54 = **DAS Metadata Schema** =
55
56 ==== **1. Interrogator** ====
57
58 * **Required:** Interrogator ID, manufacturer, model.
59 * **Optional:** Serial number, firmware version.
60
61 ==== **2. Acquisition Parameters** ====
62
63 * **Required:** Interrogator ID, acquisition ID, unit of measure, acquisition start and end time, acquisition sample rate, gauge length, number of channels, spatial sampling interval.
64 * **Optional:** Pulse rate, pulse width.
65
66 ==== **3. Overview** ====
67
68 * **Required:** Network code, location, start date, end date, point of contact.
69 * **Optional:** Digital Object Identifier (DOI), purpose of data collection, funding agency.
70
71 ==== **4. Cable Information** ====
72
73 * **Required:** Cable ID, cable bounding box.
74 * **Optional:** Cable owner, cable installation date, cable characteristics.
75
76 ==== **5. Fiber Information ('Native format')** ====
77
78 * **Required:** Cable ID, fiber ID, fiber geometry, fiber mode, fiber refraction index.
79 * **Optional:** Fiber optical length, fiber start and end location, fiber one-way attenuation, fiber winding angle.
80
81 ==== **6. Channel Group** ====
82
83 * **Required:** Interrogator ID, acquisition ID, channel group ID, cable ID, fiber ID, coordinate generation date.
84 * **Optional:** Location method, coordinate reference frame, first/last usable channel ID, uncertainty of various coordinates (x, y, latitude, longitude, elevation, depth, strike, dip).
85
86 ==== **7. Channel** ====
87
88 * **Required:** Channel group ID, channel ID, coordinates (x, y, latitude, longitude).
89 * **Optional:** Elevation above sea level, depth below surface, distance along fiber, strike, dip.
90
91 ----
92
93 === ===
94
95 = **Pre-processing Steps for DAS Data (2.5 months, 90 TB)** =
96
97 1. (((
98 **Create a Deployment Log**
99
100 * Document key details like photonics settings, duration of data collection, instances of hard disk failure, power outages, etc.
101 )))
102 1. (((
103 **Generate Geographic Coordinates**
104
105 * Assign latitude and longitude coordinates to each DAS channel for spatial referencing.
106 )))
107 1. (((
108 **Data Conversion**
109
110 * Convert the raw DAS time series data from counts to strain rate, which is more meaningful for seismic analysis.
111 )))
112 1. (((
113 **Data Decimation**
114
115 * Reduce the sampling rate from 1000 Hz to 100 Hz. This step is essential to manage data volume and focus on frequencies of interest for seismic activities.
116 )))
117 1. (((
118 **Extract Specific Time Series**
119
120 * Isolate time series data of special interest, such as those related to earthquake events, for detailed analysis.
121 )))
122 1. (((
123 **Data Hosting**
124
125 * Store the processed data on Research School of Earth Sciences (RSES) clusters and the National Computational Infrastructure (NCI) for accessibility and further analysis.
126 )))
127 1. (((
128 **Extract Data and Instrument Response from Seismic Nodes**
129
130 * Retrieve both the raw data and the corresponding instrument response characteristics for accurate interpretation of the seismic signals.
131 )))
132 1. (((
133 **Long-term Archiving and Data Sharing**
134
135 * Ensure that the data is archived in a format and location that supports long-term preservation and accessibility, such as the AuScope Distributed Acoustic Sensing (DAS) Collection.
136 )))
137 1. (((
138 **Data Access and Record Keeping**
139
140 * Maintain records and access paths (e.g., NCI local file path) for the data, including metadata and other associated records, to facilitate future research and data sharing.
141 )))
142
143 === ===
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145 === ===
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147 === ===
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149 === ===
150
151 === ===
152
153 ----
154
155 = **Silixa iDAS Setup Manual for Reoccupying/Duplicating Experiment** =
156
157 = **General Information** =
158
159 * **Experiment Name:** ~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~__
160 * **Local Date:** ~_~_~_~_/~_~__**/202**
161 * **Local Time:** ~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~__
162 * **Personnel:** ~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_
163 * **Site Condition Notes:**
164 ** [Space for detailed notes about the site condition, any upkeep performed, and changes made since the last visit.]
165
166 ----
167
168 ==== **Setup Procedure** ====
169
170 1. (((
171 **Open iDAS Box**
172
173 * Serial Number: ~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~__
174 * IP Address: ~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_~_
175 )))
176 1. (((
177 **Check Laser Lock**
178
179 * Ensure the lever on the LASER/RIGHT side of the iDAS is in the locked position (LEVER UP).
180 )))
181 1. (((
182 **Placement of iDAS**
183
184 * Position the iDAS on a stable surface.
185 * Ensure clear air flow around the fan vents.
186 )))
187 1. (((
188 **UPS Setup** (If applicable)
189
190 * Connect the UPS to a power source.
191 * Plug the NAS into the UPS using the special cable with a rectangular connector.
192 * Connect the monitor to the UPS.
193 )))
194 1. (((
195 **Peripheral Connections**
196
197 * Connect a computer monitor, mouse, and keyboard to the iDAS.
198 )))
199 1. (((
200 **GPS Antenna Connection**
201
202 * Connect the GPS antenna to the left-side socket on the front of the iDAS using a special adapter.
203 )))
204 1. (((
205 **Fibre Optic Connection**
206
207 * Clean both the fibre optic cable and the socket with a 1-click cleaner before connection.
208 * Use the guide/tip for cleaning the fibre and clean the socket without it.
209 )))
210 1. (((
211 **Powering the iDAS**
212
213 * Connect the iDAS to a power socket or UPS.
214 * Note: The iDAS turns on automatically when connected to power. Use the power button at the bottom left if it does not.
215 )))
216 1. (((
217 **Network Drive Mapping**
218
219 * Open File Explorer and select 'This PC' from the left pane.
220 * On the File Explorer ribbon, select 'More' > 'Map network drive'.
221 * Choose a drive letter from the 'Drive' list.
222 )))
223 1. (((
224 **Open iDAS Software**
225
226 * Use the link/shortcut on the Desktop.
227 )))
228 1. (((
229 **GPS Satellite Confirmation**
230
231 * Check for a green light in the top row of the software interface indicating GPS satellite detection.
232 )))
233 1. (((
234 **Lever/Interlock Adjustment**
235
236 * Lower the lever/interlock (as mentioned in step 2) before starting data acquisition.
237 )))
238 1. (((
239 **Configuration File Duplication**
240
241 * Use 'current.cfg' for duplicating previous setup.
242 * The file is located at C:/Silixa/Data/current.cfg.
243 * Copy this file to the desktop and save it with a new filename.
244 )))
245 1. (((
246 **iDAS Configuration Settings**
247
248 * Navigate to the 'Configuration' tab and click 'iDAS configuration'.
249 * Check all values under 'system'.
250 * Under 'application', enable error messages.
251 * In 'saving', select 'acoustic saving', choose 'tdms', and set the file save location and identifier.
252 * Leave default parameters in 'measure'.
253 )))
254 1. (((
255 **Mode Selection**
256
257 * Toggle between Acoustic mode, Waterfall mode, and OTDR mode to check data recording.
258 )))
259 1. (((
260 **Photograph OTDR Mode**
261
262 * Document the OTDR mode settings with a photograph.
263 )))
264 1. (((
265 **Photograph Waterfall Mode**
266
267 * Similarly, take a picture of the Waterfall mode settings.
268 )))
269 1. (((
270 **Configuration File Saving**
271
272 * Save the configuration file in .cfg format in a separate location without overwriting the existing one.
273 )))
274 1. (((
275 **Software Check**
276
277 * Ensure QFinder, Teamviewer, and Microsoft Remote Desktop are installed.
278 )))
279 1. (((
280 **Remote Access Setup**
281
282 * Open Teamviewer or Microsoft Remote Desktop.
283 * For Teamviewer, photograph the ID and password and ensure it remains open.
284 * For Microsoft Remote Desktop, record the IP address and test remote access with a separate laptop.
285 )))
286 1. (((
287 **Final Mode Setting**
288
289 * Switch to OTDR mode for ongoing operation (avoids excessive memory usage of Waterfall mode).
290 )))
291
292 ----
293
294 ==== **Important Reminders** ====
295
296 * Always ensure that the iDAS is connected to a suitably earthed power socket or UPS for safety.
297 * Regularly check the condition of all cables and connectors.
298 * Before leaving the setup, confirm that data saving is active if required.
299 * Keep a log of all actions taken during the setup for future reference and troubleshooting.
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311 [[Caption>>image:1706488806394-168.png]]
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314 [[image:https://photos.fife.usercontent.google.com/pw/ABLVV86phmYsze0lp1yzL-gs6stE23rmgKbOxcpCRhFmK9s25zf5UHBkgbFcOg=w1440-h2556-s-no-gm?authuser=0]]
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318 [[How to clean the optical connector>>image:1706488909085-143.png||alt="How to clean the optical connector"]]
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