Invention | Free Full Text | Innovative maritime unmanned systems and satellite solutions for shallow water bathymetry assessment

figure 1.
Overview of the survey area.

figure 1.
Overview of the survey area.

Invention 09 00020 g001

figure 2.
Meteorological conditions in the study area – significant wave height (Hs), wave period (T02) and wave direction (Dp) in the WW3 model during the survey period (red area).

figure 2.
Meteorological conditions in the study area – significant wave height (Hs), wave period (T02) and wave direction (Dp) in the WW3 model during the survey period (red area).

Invention 09 00020 g002
image 3.
Siebel CAMCOPTER® S-100 equipped with Areté PILLS (RAMMS) lidar system [41].

image 3.
Siebel CAMCOPTER® S-100 equipped with Areté PILLS (RAMMS) lidar system [41].
Invention 09 00020 g003

Figure 4.
Hydrographic measurements by the DriX USV during the REPMUS23 exercise.

Figure 4.
Hydrographic measurements by the DriX USV during the REPMUS23 exercise.

Invention 09 00020 g004

Figure 5.
DriX USV’s patch test survey line.

Figure 5.
DriX USV’s patch test survey line.

Invention 09 00020 g005

Figure 6.
A subset of the DriX USV multibeam data shows that sound speeds have been sampled and applied correctly, resulting in a correct representation of the flat seafloor (each color represents a different survey line).

Figure 6.
A subset of the DriX USV multibeam data shows that sound speeds have been sampled and applied correctly, resulting in a correct representation of the flat seafloor (each color represents a different survey line).

Invention 09 00020 g006

Figure 7.
A subset of the reference survey multibeam data shows that sound speeds have been correctly sampled and applied, resulting in a correct representation of the flat seafloor (each color represents a different survey line).

Figure 7.
A subset of the reference survey multibeam data shows that sound speeds have been correctly sampled and applied, resulting in a correct representation of the flat seafloor (each color represents a different survey line).

Invention 09 00020 g007

Figure 8.
Overview plots depict the general location of the offshore areas, as well as a detailed plan representing the bathymetric coverage for each data set.

Figure 8.
Overview plots depict the general location of the offshore areas, as well as a detailed plan representing the bathymetric coverage for each data set.

Invention 09 00020 g008
Figure 9.
Tide tables used to show tide heights during measurements.Can be used as [57].

Figure 9.
Tide tables used to show tide heights during measurements.Can be used as [57].
Invention 09 00020 g009

Figure 10.
Reference bathymetric surface.

Figure 10.
Reference bathymetric surface.

Invention 09 00020 g010

Figure 11.
Reference bathymetry statistics, (A)——Node density, (Second)——node standard deviation.

Figure 11.
Reference bathymetry statistics, (A)——Node density, (Second)——node standard deviation.

Invention 09 00020 g011

Figure 12.
USV MB bathymetric surface.

Figure 12.
USV MB bathymetric surface.

Invention 09 00020 g012

Figure 13.
USV MB bathymetry statistics, (A)——Node density, (Second)——node standard deviation.

Figure 13.
USV MB bathymetry statistics, (A)——Node density, (Second)——node standard deviation.

Invention 09 00020 g013

Figure 14.
Drone lidar bathymetric surface.

Figure 14.
Drone lidar bathymetric surface.

Invention 09 00020 g014

Figure 15.
UAV lidar bathymetric survey statistics, (A)——Node density, (Second)——node standard deviation.

Figure 15.
UAV lidar bathymetric survey statistics, (A)——Node density, (Second)——node standard deviation.

Invention 09 00020 g015

Figure 16.
(A)—the position of the vertical transverse profile between the shallow surface and the deep surface (Second)—Inconsistent step between shallow and deep LiDAR UAV surfaces (for contours selected between two colored squares).

Figure 16.
(A)—the position of the vertical transverse profile between the shallow surface and the deep surface (Second)—Inconsistent step between shallow and deep LiDAR UAV surfaces (for contours selected between two colored squares).

Invention 09 00020 g016

Figure 17.
SDB average in meters.

Figure 17.
SDB average in meters.

Invention 09 00020 g017

Figure 18.
Assessment of horizontal accuracy of bathymetric surfaces. (A)—MB USV, LiDAR UAV and reference survey overlay, focusing on underwater sand layers, (Second)—focuses on the same underwater sand layer, showing matches for all 3 surfaces.

Figure 18.
Assessment of horizontal accuracy of bathymetric surfaces. (A)—MB USV, LiDAR UAV and reference survey overlay, focusing on underwater sand layers, (Second)—focuses on the same underwater sand layer, showing matches for all 3 surfaces.

Invention 09 00020 g018

Figure 19.
Difference surface between reference measurements and drone lidar measurements.

Figure 19.
Difference surface between reference measurements and drone lidar measurements.

Invention 09 00020 g019

Figure 20.
LiDAR drone along-track artifacts are displayed at 20x vertical magnification.

Figure 20.
LiDAR drone along-track artifacts are displayed at 20x vertical magnification.

Invention 09 00020 g020

Figure 21.
Differences between reference surveys and SDB.

Figure 21.
Differences between reference surveys and SDB.

Invention 09 00020 g021

Figure 22.
Differences between UAV lidar measurements and USV MB measurements.

Figure 22.
Differences between UAV lidar measurements and USV MB measurements.

Invention 09 00020 g022

Figure 23.
LiDAR UAV and SDB surface difference versus reference measurement histograms.

Figure 23.
LiDAR UAV and SDB surface difference versus reference measurement histograms.

Invention 09 00020 g023

Figure 24.
Vertical profile differences between reference measurements, UAV LiDAR, USV MBES and SDB.

Figure 24.
Vertical profile differences between reference measurements, UAV LiDAR, USV MBES and SDB.

Invention 09 00020 g024

Figure 25.
Reference surface depth contours and ENC depth contours.

Figure 25.
Reference surface depth contours and ENC depth contours.

Invention 09 00020 g025

Figure 26.
MBES USV depth contours and ENC depth contours.

Figure 26.
MBES USV depth contours and ENC depth contours.

Invention 09 00020 g026

Figure 27.
LiDAR UAV depth contours and ENC depth contours.

Figure 27.
LiDAR UAV depth contours and ENC depth contours.

Invention 09 00020 g027

Figure 28.
SDB depth contours and ENC depth contours.

Figure 28.
SDB depth contours and ENC depth contours.

Invention 09 00020 g028
Table 1.
PILLS Topographic Bathymetric LiDAR Technical Specifications [39].
Table 1.
PILLS Topographic Bathymetric LiDAR Technical Specifications [39].
Technical specifications Technical specification value
aspect 41″ x 10″ x 6″ (LxWxD) | < 2 sq. ft. volume
weight <13.6 kg (30 lbs)
strength <250 watts
Transmission specifications Wavelength: 532 nm | Repetition rate: 30Hz×2
Energy per pulse: 37 mJ | Pulse width: 5.1 nanoseconds
operating height 300 meters
Width 0.9 nominal height
Running speed Manned: 100–120 knots | Unmanned: 50–60 knots
Regional search rate Manned: 57 km2/h | Unmanned: 31 km2/h
deep penetration 3×d−1
range of working temperature −20°C to 50°C
point density 25,000 points per second
Feature detection 2 m cube feature
IHO command 1A
platform Small Opportunity Aircraft (Cessna Class and Above), Unmanned
(Schiebel S-100, SeaHunter UAS), rotor

Table 2.
LiDAR AITRAC laser measurement parameters.

Table 2.
LiDAR AITRAC laser measurement parameters.

Laser parameters values
scan rate 60 Hz (2 laser combinations)
flight altitude 128 meters
points across strips 850 points/line
Scan width 115 meters
spacing between points along the track 35–50 cm
Cross track point spacing 12cm
point density 15–20 points/meter2
table 3.
Kongsberg EM 712 USV Multi-Beam Technical Specifications [45].
table 3.
Kongsberg EM 712 USV Multi-Beam Technical Specifications [45].
Kongsberg EM712 USV technical specifications
Frequency Range 40 to 100 kHz
maximum ping rate 30 Hz
Strip coverage up to 140°
Beam spacing Equiangular, isometric
roll stabilizing beam ±15°
pitch stabilizer beam ±10°
Sensor launch length 970mm
Sensor receiving length 970mm
Angular resolution 1° × 1° (100kHz)
maximum. No.Number of beams per ping 800 (dual mapping mode)

Table 4.
Water depth measurement parameters.

Table 4.
Water depth measurement parameters.

Refer to MB survey USV MB Survey Drone lidar measurement SDB-cEiiA
Total length of survey line (km) 34.65 37.90 74.20
Area measurement time (hours:minutes) 02:49 03:17 02:21
Measured average speed (knots) 6.62 6.20 40–60
Strip overlap(%) 50 15 15
Coverage area (square kilometers2) 0.78 1.94 4.56 5.08
Sea coverage area (%) 15.37 38.21 89.74 100
Measuring line spacing (meters) 50 60 100
Get period (day/month/year) June 9, 2023 15/09/2023 18/09/2023 April 1, 2023
14/04/2023

table 5.
Description of the bathymetric data set of the system.

table 5.
Description of the bathymetric data set of the system.

Refer to MB survey USV MB Survey Drone lidar measurement SDB-cEiiA Shenzhen Development Bank-Airbus
Dataset type point cloud point cloud point cloud grating grating
Dataset file format Golden Cat Mall Golden Cat Mall CSVXYZ Geography TIFF Geography TIFF
DTM meshing method cube cube basic weighted average
DTM resolution (meters) 1.00 1.00 1.00 10.0 1.20

Table 6.
Reference survey density and standard deviation details.

Table 6.
Reference survey density and standard deviation details.

node density Node standard (meters)
at the lowest limit 1 0.0
maximum Chapter 1683 0.1
meaning is 139.66 0.0
standard deviation 59.39 0.0

Table 7.
USV MB survey density and standard deviation details.

Table 7.
USV MB survey density and standard deviation details.

node density Node standard (meters)
at the lowest limit 1 0.0
maximum 3341 0.1
meaning is 110.33 0.0
standard deviation 61.77 0.0

Table 8.
Drone lidar measurement density and standard deviation details.

Table 8.
Drone lidar measurement density and standard deviation details.

node density Node standard (meters)
at the lowest limit 1 0.0
maximum Chapter 1173 2.6
meaning is 65.60 0.2
standard deviation 17.37 0.1

Table 9.
Surface histogram statistics for LiDAR and SDB relative to the reference survey.

Table 9.
Surface histogram statistics for LiDAR and SDB relative to the reference survey.

Drone lidar SDB-cEiiA
Minimum (meter) −1.3 −1.6
Maximum(m) 0.8 7.2
Average (meters) 0.2 2.1
Sexually transmitted diseases (men) 0.3 2.1

Source link

Leave a Reply

Your email address will not be published. Required fields are marked *