YellowScan Surveyor - USGS · YellowScan Surveyor World’s lightest and most accurate LiDAR...

YellowScan SurveyorWorld’s lightest and most accurate LiDAR solution for UAVs

User Manual

Version 1.1 – 26/07/2016

[email protected] ■ T.: +33(0)9 77 72 08 77 ■ www.yellowscan.fr YellowScan ■ 1, chemin du Fescau ■ 34980 Montferrier sur Lez – France

YellowScan Surveyor – User Manual 1/18

Thank you for purchasing YellowScan. The present document aims at giving you simple andstraight forward directions to use the system. Please read the full document before startingoperation.

DisclaimerThe system and all components, including software and this description, have beenmanufactured with great care to ensure its proper function . They are provided on an “as is”and “as available” basis.

The system is guaranteed against malfunction in the framework of a normal use. The housingof the system is sealed and any unauthorized opening will break the guarantee.

Should you encounter any bugs, glitches, lack of functionality or other problems, pleasecontact us by email: [email protected]. Your help in this regard is greatly appreciated.

© 2015 – 2016, YellowScan SAS. All rights reserved. Information in this document is subject to change withoutnotice. Copy or redistribution of this document is forbidden without express authorization of YellowScan.


mailto:[email protected]

Index

.............................................................................................1

Disclaimer..............................................................................2

System Installation.................................................................4

1.YellowScan Surveyor Overview............................................................................4

2.Installing YellowScan Surveyor Processing Software..............................................5

3.Mechanical Installation and Recommendations.....................................................6

4.Lever Arm Measurement....................................................................................7

Real-time Operation................................................................8

5.Running YellowScan Surveyor System..................................................................8

6.Data Files....................................................................................................... 9

7.Simplified Work-flow...................................................................................... 10

8.Advanced settings.......................................................................................... 12

Post-Processing Work-flow.....................................................13

1.Downloading Raw INS Data...............................................................................13

2.POSPac UAV Post-Processing Work-flow..............................................................14

3.Advanced settings in POSPac............................................................................16

Physical Dimensions..............................................................17


System Installation

1. YellowScan Surveyor Overview

1. Power indicator: Lights green when the system is powered on.2. Battery indicator: For future use3. Operation button: Quick press to start/stop recording (Refer to Recording indicator). Long press (more than 3 seconds) to initiate system shutdown.4. Recording indicator: Fast blink when waiting for satellite reception. Solid on when the system is ready to operate. Slow blink when recording data.5. IMU indicator: IMU not aligned when off. Quick blink when coarse leveling. Slow blink infull navigation6. GNSS indicator: Quick blink when tracking 0 to 2 satellites. Slow blink when tracking more that 3 stalellites.7. RTK indicator: Slow blink when operating in RTK mode. Also blinks once when receiving camera synchronization information.8. GNSS antenna connector: SMA connector to plug GNSS antenna.9. Radio communication port: Plug radio modems for RTK operation or communication with the control station.10. Camera synchronization port: Plug synchronization cable to the camera to time-stamp camera triggers.11. External power port: Connect to an external power source (9-18V).


2. Installing YellowScan Surveyor Processing SoftwareYellowScan processing tools are operating under Linux and Windows systems, in the formof a QGIS plugin.

Download QGIS from http://www.qgis.org and install it.

Copy the yellowReaderSurveyor_Plugin directory from the DVD into

/home/username/.qgis2/python/plugins/ (for Linux users) orC:\Users\Username\.qgis2\python\plugins\ (for windows users). Create python andplugins directories if needed.

Start QGIS and go to menu plugins > Install plugin, select yellowReader SurveyorPlug-in, and click Install plug-in.

A new icon appeared in the QGIS panel.


http://www.qgis.org/

3. Mechanical Installation and Recommendations The YellowScan Surveyor must be attached to the UAV using damped mount, to avoid

vibration transmission that could affect the data quality.

YellowScan Surveyor's GNSS antenna should always been mounted on the top of every

other components of the UAV to avoid any mask in GNSS reception that could affectthe data quality.

The GNSS cable to run as far as possible from power cables and batteries.

A clearance of 30 cm from other active GNSS antenna must be fulfilled in order to

avoid any interference. In case the UAV system uses an active antenna it isrecommended to used a GNSS signal splitter to share a common antenna for both theUAV system and YellowScan Surveyor. In order to maintain flight safety, it isrecommended that the antenna is powered by the UAV flight system. The antenna usedmust be the antenna provided by YellowScan.


4. Lever Arm MeasurementAll lever arms are considered in the YellowScan (body) coordinate frame, and are measuredFROM the YellowScan, TO the GPS antenna. The sign of the value depends on the direction:If Z and z (see picture below) have the same direction, then the value is positive. If they haveopposite direction (Z and z on the example below), then the value is negative.

Lever arm must be measured from the optical center of the scanner.


Xx>0

Yy>0

Z

z>0

Real-time Operation

5. Running YellowScan Surveyor System Make sure the battery is correctly charged

Make sure the USB stick is plugged into the system.

Switch the power ON. The green LED lights continuously. The onborad computer is

starting up.

After a few seconds the GPS and IMU LEDs will briefly light. The INS is ON.

The Scanner light is blinking quickly. The system is waiting for satellite reception.

Once satellite reception is sufficient, GPS LEDs is blinking one per second. Once

synchronized, the scanner LED will light continuously.

The system is now ready for operation.

Quick press the yellow button to start data recording. The scanner LEDs will start

blinking once par second.

Quick press the yellow button to stop recording. The scanner LEDs will light

continuously. The system is ready again for operation. You can come back to theprevious step or go to the next one.

Long press the button to shut the system down. Wait for the scanner LED to turn

off. You can now switch the power off.


6. Data FilesYellowScan data is recorded on the USB stick. It is composed of 2 different files, for eachstart/stop procedure :

*.apx: the INS data, containing both IMU and GPS real-time recordings.

*.puck: the scanner data.

These files share the same name, composed by the date and time of the record:YS-YYYYMMDD-HHMMSS.apx/puck.


7. Simplified Work-flowThe simplified work-flow allows to process the data into point clouds right after flight. Itbrings a convenient way to check the data for coverage and overlapping. However, this solutionprovides data at a lower accuracy than the one expected after trajectory post-processing.

Insert the USB stick in your computer.

Select the data files you want to process and copy them to your hard drive.

Click ([SURVEYOR] Select .apx file / re-open pop-up) to select the .apx file

of your project. This will display the trajectory in green and open the YellowScanSURVEYOR window.

In the YellowScan SURVEYOR window, Processing tab:

You can specify the base name of the output file.

The default format for output file is .las, but you can also export lidar data as .txt

file. In the latter case you can choose which data field to export in the text file.

Click on Change Projection to select the geographical reference system of the output

data.

Select the flight line you want to process based on the GPS time.


To select flight line 1, click on Line 1, then use the tool to select the starting

point of the trajectory you want to process. Click on Set button. The start time willbe displayed in the table. Select the end of the line and click Set button. The endtime will be displayed in the table. Once Line 1 selection is completed, the currentline is displayed in orange.

To select a new line, click + button and process Line 2 as explained previously.

Already selected line will be displayed in grey.

Press Save button to backup your project.

Once your line selection is complete, you can process each individual line, or

multiple lines. Click on their name (Line 1, Line 2...) to selecting them, hold Crtlkey for multiple selection, or click on the upper left cell to select all of them. PressProcess.

Process trajectory will output a space delimited text file containing the position,

orientation and accuracy of the laser center of measurement.

The above process will create the following structure in the directory containing theraw lidar files:

YS-YYYYMMDD-HHMMSS.puck (lidar file)

YS-YYYYMMDD-HHMMSS.apx (INS file)

YS-YYYYMMDD-HHMMSS.ysc (project file)

YS-YYYYMMDD-HHMMSS (directory created at launch of the YellowScanSURVEYOR plugin)

➔ apxtxt

YS-YYYYMMDD-HHMMSS_apx.txt (trajectory file)

➔ las (directory containing output LAS files)

➔ txt (directory containing output TXT files)

Output files are located in YS-YYYYMMDD-HHMMSS/las for LAS files or in YS-YYYYMMDD-HHMMSS/txt for text files.


8. Advanced settingsIn the Advanced tab of the YellowScan Surveyor window, you can:

Apply misalignment angles provided by YellowScan or your local distributor,

Select the scanner angle range to process. Starting with a negative value and ending

with a positive value will process the data looking below the drone. Starting with apositive value and ending with a negative value will process the data looking abovethe drone.


Post-Processing Work-flowIn order to get the highest point cloud accuracy, it is strongly recommended to post-processthe trajectory. This consists of a differential GNSS post-process using a GNSS base stationfollowed by a forward and backward GNSS-Inertial post-processing.

1. Downloading Raw INS DataIn order to download the raw INS data the user must connect to the INS board using anethernet cable.

Connect the INS to your PC using an Ethernet cable.

Set the PC to a static IP address. The address should be in the range 192.168.9.XXX,

with XXX ranging from 1 to 252.

Open a web browser and connect to the IP address 192.168.9.253

Enter login (admin) and password (password).

In the menu on the left side, select DATA LOGGING

Browse the internal memory to find the record with the name corresponding to your

date of acquisition. Please note that time is in UTC reference.

Click on the file name to start downloading the file and save it in your project folder.


2. POSPac UAV Post-Processing Work-flowThe Position and Orientation System Post-processing Package UAV (POSPac UAV) is the post-processing software package from Applanix Corporation. It is a simple to use, integrated suite‐ ‐of software utilities designed to import and process data recorded by the APX-15 UAV boardintegrated in the YellowScan Surveyor. POSPac includes direct exterior orientation generationwith calibration and quality control at a rate of 200Hz.

Launch POSPac UAV software

Create a new project by clicking the icon resulting the following window:

Import T04 file previously downloaded from the INS, by clicking the icon . The

antenna model should be Applanix AV39. The software will check data quality ondisplay the real-time trajectory on the screen.

You can then import the base station data file (Rinex file) or download it using the

on-line service Smart Base or Single Base depending on your license option (Find

base station). The base station should be displayed on the screen and as well as a baseline between the base and the rover position.

In the case of a manually imported base station, left click on the base position to select

the base point. Check base coordinate position (right click, Coordinates manager) andagain right click Set Base Station.

Launch the GNSS-Inertial processor and check lever arm measurements in the

project settings . Once checked you can click on Run button.


Once completed, the post-processed (SBET) trajectory is displayed on the screen.

Export the post-processed solution as an ASCII file, by clicking on the Export icon

Save your POSPac project in case you need to modify it later.

Go back to you project in QGIS and select the exported file as the Post ProcessedSolution, select your flight lines and click again on Process button. This will reprocessLAS files using the post-process trajectory. Please not that previous LAS files will beoverwritten, unless you have changed the Basename field. Save your project.


3. Advanced settings in POSPacIn the project settings , Export area, you can adjust settings related to the mapping frame.

By default, POSPac outputs solution in WGS84/UTM, but you can select a custom mappingframe by un-checking “Default Mapping Frame” and clicking on the “Mapping Frame” buttonon the bottom of the window. Z-reference is selected in the “Height Options” area by selectingeither “Ellipsoid” or “Orthometric” with the proper Geoid Model.

You can then export the post-processed solution as an ASCII file, by clicking on the Export

icon .

Back in QGIS plugin you should check “Use mapping frame form post-processed solution” inorder to process point clouds using the Mapping Frame selected in POSPac. In this case“Change Projection” button has no effects.


Physical Dimensions


For any question or suggestion, feel free to contact us :

YellowScan1, chemin du Fescau

34980 Montferrier sur Lez, France

+33 977 720 877

[email protected]


YellowScan Surveyor - USGS · YellowScan Surveyor World’s lightest and most accurate LiDAR...

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