Choosing Unmanned Surface Vehicles for Hydrographic Surveying

The usage of unmanned surface vehicles (USVs) is rapidly growing in hydrographic surveying. It has revolutionized the field of hydrographic surveying by making things easier and safer for all those involved. USVs help with surveys being more efficient and are also much more cost-effective compared to older methods that were used.

If you are ever planning to take one of these vehicles for a spin and use it for your next survey, you have to know what you are looking for and get as much information as needed. Luckily, we are here to help you understand how things work and will introduce you to the wonderful world of unmanned surface vehicles used in hydrographic surveying.

What are Unmanned Surface Vehicles (USVs)?

USVs are small survey boats that are equipped with all the necessary tools for underwater mapping and taking hydrographic measurements. They operate on the surface of water without the need for a crew. They are operated remotely and can even function autonomously if you programme them with pre-set routes.

They are very useful tools that can help in mapping water depths and underwater features for nautical charting, navigation safety, and marine construction. Usually, they come equipped with such tools as echo sounders, GPS/INS, and other sensors, but depending on the size and type, they can carry much more surveying equipment with them if needed.

In the past, surveying large masses of water traditionally required manned boats used to make passes. This was not only time-consuming, but risky for the crew and all the people involved. Today, USVs allow you to stand safely on land with a remote controller in hand, conducting the survey with ease. You don’t need to put yourself at risk, nor does it require larger crews to conduct a survey.

Beyond hydrography, unmanned surface vehicles are used in various other industries like oceanography and environmental research, dredging and coastal engineering, hydrology and water management, and environmental monitoring.

Popular Unmanned Surface Vehicles

Spec	AQUA M20	AQUA M10
Model	AQUA M20 Autonomous Bathymetric Survey USV	AQUA M10 Autonomous Bathymetric Survey USV
Image
Dimensions (L×W×H)	1180 × 700 × 390 mm	950 × 500 × 350 mm
Weight (without battery)	12.8 kg	6 kg
Material	Nano carbon fiber polymer composite	Nano carbon-fiber polymer composite
IP Rating	IP67	IP67
Wind–wave resistance	Beaufort Cat 3 wind, Cat 2 waves	—
Propulsion	Electric drive, differential/reversible steering	Electric drive; up to 7 m/s; differential/reversible steering
Cruise speed	7 m/s max	—
Endurance	5.5 h @ 2 m/s	—
Battery	33 V, 50 Ah detachable lithium	33 V, 50 Ah, detachable Li-ion
Default echo sounder	200 kHz; 5° beam; 0.15–100 m; ±1 cm ±0.1% D	200 kHz, 5° beam, 0.15–100 m depth, accuracy ±1 cm ±0.1%D
GNSS antennas	Dual (front and rear)	Dual antennas
GNSS constellations	GPS, BDS, GLONASS, Galileo, QZSS, SBAS, IRNSS	GPS/GLONASS/Galileo/BeiDou/QZSS/SBAS/IRNSS
Remote control	Up to 2.5 km; 7.2-inch display	7.2-in screen; up to 2.5 km connection distance

Applications of USVs in Hydrographic Surveying

Modern USVs are created with the aim of being capable of executing various missions. Thanks to the ease of use and all the equipment they are able to carry, these useful surveying tools can help us perform various tasks, no matter how difficult they might be.

Here are just some of the fields where USVs are used:

Bathymetric surveys: The primary use of USVs is conducting bathymetric surveys, which involve measuring water depth and underwater terrain for map creation. This way, safe water navigation is ensured, as well as helping us to better understand underwater geology.
Pre- and Post-Dredging Surveys: USVs are commonly used to survey dredge sites because they can operate in the vicinity of dredging equipment without putting personnel in harm’s way. Dredging projects require frequent surveys before, during, and after dredging to guide operations and verify depths.
Environmental monitoring: USVs can help collect data on water quality, salinity, temperature, and various other environmental factors. The collected data can be further used to assess the health of the water and potentially identify threats to the local marine life.
Port and Harbor Surveys: Port authorities sometimes deploy USVs for routine harbor surveys, berth depth checks, and hazard detection. USVs can operate around busy ports with minimal disruption and even at night if needed, and perform tasks faster and much more safely.
Search and rescue operations: With the help of sonars and various pieces of equipment, USVs can search for submerged vessels or various other objects located underwater.
Offshore energy exploration: Unmanned surface vehicles can be used in offshore energy exploration projects to collect data on the seafloor and thereby help identify potential sites rich in oil or gas.

Benefits of Using USVs in Hydrographic Surveying

USVs are much more helpful in hydrographic surveying than you think. These surveying tools have become popular for a reason, and it is mainly due to all the advantages that they bring to the table and how they make the lives of surveyors easier.

Efficiency: USVs can collect much more data than traditional surveying vessels and even do it in shallow and hard-to-reach places. They can do it faster and with much less effort on your side.
Cost-Effectiveness: Gathering a traditional surveying crew within a vessel costs a lot, compared to a single USV, which is much cheaper to operate and maintain. A single piece of equipment can complete the job of an entire crew, and it even leaves a smaller carbon footprint, lessening the impact on the environment.
Safety: Hydrographic surveys can be quite dangerous, especially during harsh weather conditions, making it much more dangerous for the people involved. The use of a single USV significantly reduces the risk factor and eliminates the potential for injury during surveys.
Quality Data: Unmanned surface vehicles are equipped with all sorts of advanced surveying tools, including high-tech sensors and GPS technologyf. The level of technology ensures that the collected data is precise and more accurate.

Challenges of Using USVs in Hydrographic Surveying

Of course, not everything related to USVs is great. Some situations or parts of its usage represent a challenge, even for the most experienced surveyors. While there are many benefits, there are still a few disadvantages that USVs represent for hydrographic surveying.

Navigation: To navigate safely, USVs rely on GPS technology. Unfortunately, potential signal interferences can greatly impact their ability to collect accurate data.
Weather Conditions: USVs can be impacted by bad weather conditions, such as waves and wind. It could cause signal interference and prevent them from gathering accurate data in those types of situations.
Data Processing: To correctly process the collected data, you are going to require specialized software. USVs are capable of collecting enormous amounts of data, and you need to make sure you have a way of interpreting it correctly.

How to Choose the Right USV for Hydrographic Surveying

Now that we have all the details about hydrographic surveying and the usage of unmanned surface vehicles out of the way, it is time to explain the steps of picking the one that you need. Being that there are different models out there, you will need to concentrate on a few key characteristics that will benefit you.

Sensors: Make sure that the USV has the required sensors for the type of survey you are planning to do. For instance, if you are conducting bathymetric or environmental monitoring, be sure to get one that has the needed sensors for those types of surveys.
Size and maneuverability: The size and the effective movement of the USV depend on the shallowness of the mass of water you are covering or its size. If you are planning to cover a much vaster portion of water, you will need a USV that is stronger and can deal with waves and water impacts.
Data processing: Every piece of software that you are working with has to be compatible. So make sure that the USV matches the type of software that you are using in order to interpret and analyse the collected data later on.
Autonomy: Some USVs operate via remote control, while others can do so autonomously. Depending on the type of project and your convenience, you can pick one that is more suitable for you.
Cost: The final and, in most cases, most important thing that you have to think about is cost. The best way to go about it is to determine if the overall cost of using a USV will go beyond traditional surveying methods.

FAQs

Take a look at a few added answers regarding USVs and their use within hydrographic surveying.

What is an Unmanned Surface Vehicle?

An Unmanned Surface Vehicle (USV) is a small, crewless boat that operates on the surface of the water. USVs can be either remotely controlled by an operator on land or pre-programmed to function autonomously along a set route. They are equipped with advanced sensors and tools for collecting hydrographic data.

What is the primary purpose of a USV in hydrographic surveying?

The main purpose of a USV in hydrographic surveying is to map water depths and underwater features. This data is used for creating nautical charts, ensuring navigation safety, and supporting various other applications like marine construction and environmental monitoring.

What is the difference between ASV and USV?

The terms autonomous surface vehicles (ASV) and unmanned surface vehicles (USV) are often used interchangeably, but essentially refer to different things. The main difference is that ASVs are used without remote control and are preprogrammed based on routes to do their work. On the other hand, while you can also program USVs to work autonomously, they are mainly controlled via remote controllers.