Best Answer What Is Drone Technology And How Do Drones Work

Drones have become ubiquitous in today’s fast-paced technological world, but have you ever paused to wonder, “how does drone technology work?” From aerial photography to package delivery, drones serve various purposes. In this comprehensive guide, we demystify the technology that makes drones fly, navigate, and perform tasks autonomously.

In this simple-to-read essay, we will explain what a drone is and how it operates. As a result of ongoing research and development and substantial financial investment, new and improved UAV drones are often released into the market.

Below, we’ll go through the UAV features found on today’s most widely-used drones, the ones that always seem to be at the cutting edge of the drone industry. Most unmanned aerial vehicles will have the same internal architecture.

There is also a list of the best camera-equipped drones available right now.

Everything from the drone’s aerodynamics and the materials used in its construction to the UAV’s circuit boards, chipset, and software are included in the realm of unmanned aerial vehicle technology.

The DJI Phantom is a popular model of drone. Professional aerial cinematographers love these drones.

As a complete system, Phantom UAVs are perfect for demonstrations of drone technology. The UAV, as well as the camera gimbal and stabilizer, are all included. In addition, they produce some of the most advanced drones available today.

Drone technology has improved rapidly in recent months, with new releases including the DJI Mavic Mini, Mavic 2, Mavic Air 2, Phantom 4 Pro V2.0, Yuneec Typhoon H3, and Autel Evo 2.

Unmanned aerial vehicle (UAV) drone technology is advancing at a lightning rapid rate. In the article linked below, you’ll find the most recent developments in drone technology. All of the information and links on this page are current.

How Drones Work

A typical unmanned aircraft is made of light composite materials to reduce weight and increase maneuverability. This composite material strength allows military drones to cruise at extremely high altitudes.

UAV drones are equipped with different state-of-the-art technology such as infrared cameras, GPS, and laser (consumer, commercial and military UAV). Drones are controlled by remote ground control systems (GSC) and are also referred to as ground cockpits.

An unmanned aerial vehicle system has two parts, the drone itself and the control system.

The nose of the unmanned aerial vehicle is where all the sensors and navigational systems are present. The rest of the body is full of drone technology systems since there is no space required to accommodate humans.

The engineering materials used to build the drone are highly complex composites designed to absorb vibration, which decreases the sound produced. These materials are very lightweight.

In What Ways Do Drones and Unmanned Aerial Vehicle Technology Differ

The science and technology underlying the DJI Phantom UAV are explored here. In addition, we have a wealth of data about the newest drones available and the technology they use.

Those interested in learning more about certain aspects of drone technology will find a wealth of resources at their fingertips. Here’s an excellent post that provides a general overview of drone parts. This provides details on the various parts used in common drones.

Various Shapes and Sizes of Drones.

There is a broad range of sizes for unmanned aerial vehicles (UAVs), the biggest of which are often reserved for military applications (like the Predator). Unmanned aircraft systems, which are the next size up, are fixed-wing aircraft that can take off and land on shorter runways. Common applications include land surveying and anti-poaching operations, both of which need coverage of wide regions.

Robots Capable of Vertical Takeoff and Landing

The next size up in drones is the vertical takeoff and landing varieties. The vast majority of these are quadcopters. Drones with vertical takeoff and landing capabilities are referred to as VTOL. “Vertical Take-Off and Landing” is the literal translation of the acronym VTOL.

Many of the most up-to-date palm-launched small UAV drones, like the DJI Mavic Air 2, have advanced vertical takeoff and landing (VTOL) technology.

Radar Positioning & Return Home

Newer drones are equipped with not one but two GNSS (Global Positioning Satellite) receivers.

Drones may operate in both Global Navigation Satellite Systems and non-satellite flight modes. In the case of DJI drones, for instance, pilots have the option of using either P-Mode (GPS & GLONASS) or ATTI mode (which does not utilize GPS).

Drone applications like 3D mapping, landscape surveying, and SAR (Search and Rescue) operations all rely heavily on very precise navigation while in flight.

A GNSS satellite search and detection process begin as soon as the quadcopter is powered on. The Satellite Constellation technique is used in high-end GNSS systems. A satellite constellation is essentially a series of satellites that operate in unison to provide overlapping coverage and are synchronized to do so. During a satellite’s pass or coverage, it is visible above the horizon where you are.

Drone UAV GNSS On Ground Station Remote Control

On the screen of your remote, the following signals will appear thanks to radar technology:

Display the current position and location of the drone in reference to the pilot; Indicate when a sufficient number of satellites have been identified by the drone’s Global Navigation Satellite System (GNSS) and the drone is ready to take off. Save your home’s coordinates for the “Return To Home” safety function.

There are now three main varieties of drone Return to Home technologies found in today’s UAVs.

The pilot called for homecoming by pushing a button on the remote or an app.
When the UAV’s battery is critically low, it will return to the takeoff location automatically.
If the connection between the UAV and the remote controller is lost, the UAV will return to its starting location.

The Mavic Air 2’s cutting-edge technology allows it to detect impediments during autonomous landing.

Technology for Identifying Dangers in Order to Avoid Them

Modern, high-tech drones have included protections against accidental collisions. These use software algorithms and simultaneous localization and mapping (SLAM) technology to convert pictures captured by the drone’s cameras into 3D maps that may be used for obstacle avoidance. In order to detect and avoid danger, these systems combine one or more of the following sensors:

Monocular Vision Ultrasonic Infrared Laser Rangefinder (Lidar) Time of Flight (ToF)

All six sides of the DJI Mavic 2 Pro and Mavic 2 Zoom are equipped with obstacle detection. Vision and Infrared sensors are used in the Mavic 2’s vision system, resulting in 360-degree Obstacle Sensing.

Superior drone technology may be found in the DJI Mavic 2’s obstacle-detecting system. The Mavic 2 can detect impediments in its path and avoid them by swerving to the side. It is capable of the same feat while flying in reverse. Or, if you’re unable to navigate around it, you can always hover.

The DJI Mavic 2 and Mavic Air use this technology, called APAS (Advanced Pilot Assistance System), to help pilot the drones.

The Skydio 2 drone was introduced in the winter of 2019/2020. This also has 360-degree obstacle dodging.

Skydio 2’s autonomous technology can see and compute what’s going on in its vicinity. The system will thereafter be able to accurately forecast future events and act on those predictions many times per second.

With its six 4K cameras, the Skydio 2 quadcopter creates a detailed 3D model of its environment, including obstacles like trees, people, animals, vehicles, and structures.

Control Systems, Inertial Measurement Units, and Gyroscopes

The UAV drone is capable of stable flying thanks to gyro stabilization technology.The drone can fly or hover quite smoothly because of the gyroscope, which responds very instantaneously to the forces acting on it. The gyroscope relays crucial navigation data to the aircraft’s brain.

In order to function, the inertial measurement unit (IMU) employs a system of accelerometers to determine the rate of acceleration at the moment. Through the use of one or more gyroscopes, the IMU can identify changes in rotational characteristics including pitch, roll, and yaw. Some Inertial Measurement Units (IMU) include magnetometers built in to help with orientation drift calibration.

A drone’s flight controller would be useless without the Gyroscope that is a part of the inertial measurement unit. The drone’s brains are located in the flight controller.

This excellent essay discusses the use of inertial measurement unit (IMU) technology and gyroscopes in drones.

Drive Systems for Unmanned Aerial Vehicles

Drone technology, including the motors, electronic speed controls, and propellers, lifts the UAV into the air and allows it to fly in any direction, including a hover. When it comes to a quadcopter’s motors and propellers, you’ll find that they come in pairs, with two pairs turning clockwise (CW Propellers) and two pairs rotating counterclockwise (CCW Propellers).

They get information on how to fly or hover via the drone’s flight controller and electronic speed controls (ESC).

The most cutting-edge motors and propulsion systems for UAV drones include the following parts;

The Stator Windings, Bearings, and Cooling System of a Motor
Modulators of Velocity Electronic
Propeller Wiring Connector for ESC Upgrades
Drone motors receive signals from the Electronic Speed Controllers that provide information about speed, braking, and fault tolerance.

Read this article, which has helpful videos, to learn more about what a drone camera is and how it operates.

Telemetric Flight Parameters in Real Time

Almost all drones nowadays can be piloted and the current flight telemetry may be monitored and recorded using a Ground Station Controller (GSC) or a smartphone app. Some examples of telemetry information that may be shown on the remote controller for a UAV include its range, altitude, speed, GNSS signal strength, remaining battery power, and any alerts.

The FPV (First Person View) system is used by several UAV drone ground controllers to transfer video from the drone to the controller or mobile device.

Drone technology for restricted airspace

The newest drones from DJI and other brands include a “No Fly Zone” function to help boost flying safety and avoid mishaps in prohibited regions.

The Federal Aviation Administration establishes and classifies the no-fly zones (FAA). UAV firmware upgrades allow manufacturers to alter the no-fly-zone drone technology.

Drone Technology With Built-In GPS And A “Ready To Fly” Mode

Once the compass has been adjusted for local conditions, it will actively hunt for GPS satellites. When more than six are detected, “Ready To Fly” mode is activated and the drone may take off.

Internal Compass & Failsafe Function

Provides precise position data to the UAV drone and its control system. If communication between the drone and its controller suddenly ceases, the drone may be programmed to return to a previously designated home point. Sometimes called a “fail-safe function,” this is a precaution in case anything goes wrong.

Drone Technology for Real-Time, First-Person-View Live Video Transmission

“First Person View” abbreviates to “FPV.” The footage captured by the camera installed on the UAV is sent in real time to the pilot on the ground. Instead of controlling the plane from their current location on the ground, the pilot is controlling it as if they were sitting within it.

First-person view (FPV) enables the unmanned aircraft to travel considerably greater distances and fly at greater altitudes than would be possible if the pilot were observing the flight from the ground. With the first-person perspective, you can navigate around obstacles with more precision.

FPV technology has made it simple for unmanned aerial vehicles to navigate tight spaces like homes, woods, and city centers.

Without FPV live video transmission technology, the drone racing league could not have grown and developed at such a breakneck pace.

This first-person-view system transmits and receives video through radio waves. The drone incorporates an antenna and a wireless FPV transmitter that can operate on many frequencies. The live video signals may be received by the remote control unit, a computer, tablet, or smartphone, depending on the drone.

The quality of the live video stream from the drone depends on the connectivity with ground control.

The FPV live video range of the DJI Mavic 2 is 5 miles (8 km), and the video quality is 1080p.

Drones like the DJI Mavic and Phantom 4 Pro, which are a little older, can send live video up to 4.3 miles (7 km). DJI’s newest transmission technology, Lightbridge 2, is built into the Phantom 4 Pro and Inspire 2.

When it comes to transmitting high-definition images wirelessly, drones like the DJI Mavic have raised the bar by reducing latency and boosting maximum range and dependability thanks to integrated controllers and clever algorithms.

Drone technology that can stream live video and maximize signal strength is interesting. A fantastic read on “Understanding FPV Live Video Transmission” may be found here.

First-Person Viewing on 4G and LTE Connections

There was an announcement of a new kind of live video in 2016 that uses the 4G / LTE network to broadcast, allowing for minimal latency and infinite range. The Sky Drone FPV 2 is the first drone to have this technology, which consists of a camera module, data module, and 4G / LTE modem.

Updated Firmware with a Connector for a Flight Advisers Display

A micro-USB connection connects the flying control system to a PC Assistant. The UAV may be set up and the firmware updated in this way.

An unmanned aerial vehicle, or UAV, may be thought of as a flying computer with a camera or sensor connected to it. Firmware software in drones, like that found in computers, sends orders to the hardware parts of the aircraft or controller.

Firmware updates are often released by drone manufacturers to address issues and provide new capabilities to the aircraft, remote control device, and software.

Instruments for Flying with LED Lights

You may find them on the drone’s front and back. Drones often have LEDs of green, yellow, or red.

The UAV’s forward position is shown by its LED indicators lighting up.

The many states of the drone, such as when it is powered on, upgrading its firmware, and in flight, are indicated by LED lights located on the drone’s back.

In order to get the most out of your quadcopter, it’s a good idea to learn what each of the lights means.

The user documentation that comes with every drone will include a chart that explains the various LED blinking patterns.

Drone Command and Control Unit

This component is the 5.8 GHz wireless communication system used by the DJI Phantom 3. “Ground control” refers to the base from which a remote-controlled system is operated. Before the drone ever leaves the manufacturer, it should have been linked with its controller on the ground.

Reception System for Unmanned Aerial Vehicles

Under the UAV is where you’ll find the technology connection button for the 5.8 GHz receiver.
Almost all modern drones are compatible with frequencies between 2.4 and 5.8 GHz.

Long-Range UAV Equipment

This is a radio transmitter and receiver that can typically transmit and receive signals in the 2.4 GHz range. In a clear, open region, it may increase the distance at which a smartphone or tablet can communicate with a drone.

There’s a maximum transmission range of 700 meters. Both the MAC address and the network name of a range extender are unique for each device (SSID).

The brand new DJI drones have a 5 mile range right out of the box (8 km).

The other major manufacturers’ older drones can’t go as far as DJI’s latest models. However, range extenders, which may increase that distance, are a hot commodity.

Smartphone App Featuring Ground Station Function

In today’s world, the vast majority of unmanned aerial vehicles (UAVs) may be piloted using a remote controller or a smartphone app available on major app stores like Google Play and the Apple App Store. The drone may be operated completely via the app.

The DJI Go 4 app is one example of a manufacturer-specific software.

Unmanned Aerial Vehicles With Superior Video Capture

Drones from DJI, Walkera, Yuneec, and other brands now come equipped with cameras capable of recording 4k video and 12 megapixel stills.

The cameras used in early drones were not optimal for shooting from above. Due to the wide angle lens used, there was noticeable barrel distortion in these above pictures.

To counter this, modern 4K video drones like the DJI Mavic series, DJI Inspire 1, Phantom 3 Professional, and Phantom 4 all have cameras optimized for aerial photography and filmmaking.

Professional aerial footage should be shot with a DJI Inspire 2 drone with a DJI Zenmuse X7 camera. When paired with the Zenmuse X7 camera, the Inspire 2’s image processing system, CineCore 2.1, can capture footage at up to 6k in CinemaDNG/RAW and 5.2k in Apple ProRes.

Producers in Hollywood often employ the Inspire 2. In reality, the Inspire 2 was used to capture all cinematic-quality aerial and ground views in the short film The Circle.

Drones With Zoom Cameras

Many gimbals with built-in optical and digital zoom have recently entered the market.

DJI has introduced the Zenmuse Z3, a stabilized aerial zoom camera designed for stills. The Zenmuse Z3 was perfect for industrial uses due to its 7x zoom, which consisted of an optical 3.5x zoom and a digital 2x lossless zoom, giving the camera a 22-77mm equivalent focal length.

DJI then unveiled the Zenmuse Z30 camera shortly after. The powerful Zenmuse Z30 aerial zoom camera combines a 30x optical zoom with a 6x digital zoom, for a maximum of 180x magnification.

This opens the door for more widespread industrial applications, such as assessing cell towers and wind turbines for damage. Zenmuse may be used with the DJI Matrice series of drones.

The camera on the Walkera Voyager 4 has an astounding 18x zoom. The Voyager 4’s camera can shoot in any direction with its 18x optical zoom. It’s capable of shooting in 4k at 30 frames per second. 3-axis brushless stabilization gimbal technology is used in the HD picture transmission system.

And now Walkera has unveiled their newest Voyager 5 model. This is an astounding 30x optical zoom camera.

The Voyager 5 has many backup systems, including two sets of GPS receivers, two sets of gyroscopes, and three sets of batteries. Additionally, it may be equipped with a low-light night vision camera and a thermal infrared camera as an option.

Stabilizers, Pan/Tilt Mechanisms, and Other Motion Control Devices

Taking stable photographs, videos, or 3D models from above requires gimbal technology.

The camera may be tilted in flight to capture unusual perspectives, thanks to the gimbal. Most significantly, the gimbal lessens the shakiness of the camera. Most often seen are gimbals with two different operating modes and three axes of stabilization. There are both regular and first-person-view modes available.

These days, almost every kind of drone comes equipped with a camera and gimbal. DJI’s Zenmuse series is the industry standard when it comes to aerial gimbal technology. The construction of gimbals for drones is discussed in further detail here.

Drones without gimbals for use in filmmaking.

The H22 camera chip was introduced by Ambarella at CES a few years ago. These H22 chips enable the camera to record 4K UHD video and provide electronic image stabilization, so the gimbal may be omitted.

UAVs Equipped With Sensors For Use In Sensor Fusion Map Construction And 3D Modeling

Buildings and landscapes are being modeled in 3D with the use of Lidar, Multispectral, and Photogrammetry sensors. Drones equipped with thermal and low-light night vision sensors are being utilized to survey buildings and outdoor areas for use in agriculture, firefighting, and search and rescue operations.

Drones may be equipped with a wide variety of sensors, and the data collected by these sensors can be combined in software for enhanced accuracy. The following describes how sensor fusion works;

For the goal of enhancing application or system performance, sensor fusion is software that cleverly integrates data from several sensors, such as a thermal camera and a normal RGB camera sensor. When data from numerous sensors is combined, the mistakes introduced by using just one sensor are cancelled out, allowing for more precise position and orientation calculations to be made.

Drones equipped with multispectral sensors, for instance, may generate DEMS of landscapes, which in turn can offer precise information on the state of plants, animals, and trees.

The first commercially available drones with Time-of-Flight (ToF) sensors debuted the same year. ToF (time-of-flight) sensors, commonly known as “Flash Lidar,” may be used alone or in conjunction with RGB and conventional lidar sensors to give several solutions in a wide range of industries.

ToF depth ranging camera sensors have several applications, including but not limited to: object scanning, interior navigation, obstacle avoidance, gesture recognition, tracking objects, measuring volumes, reactive altimeters, 3D imaging, and augmented reality games.

Rapid-fire LiDAR Time-of- The ability of flight cameras to determine distances to objects in a scene with a single photo is a significant advantage over competing technologies.

The UAV is designed to autonomously fly over a region utilizing waypoint navigation in order to collect data for lidar and photogrammetry mapping. The drone’s camera may capture pictures at intervals of half a second or a second. The 3D pictures are made by combining these photographs using photogrammetry software.

DroneDeploy is a frontrunner among 3D mapping software developers. Their Live Map and mobile app are used in several industries for 3D mapping and modeling. Their software is compatible with the vast majority of modern drones, and they provide a tailored solution for the agricultural industry.

Taking pictures with a stabilized drone that have a good quality is crucial. Also crucial is the use of state-of-the-art photogrammetry software to convert the raw picture data into usable topographic maps and 3D models. Here are examples of top-tier drone mapping software:

Solution for Drone-Deployed Three-dimensional Mapping
Photogrammetry Program Pix4D-Mapper
The AutoDesk ReCap Photogrammetry Software: Orthophoto and 3D Models
3DF Software for Performing Photogrammetric Surveys with Zephyr
The Photogrammetry Software Agisoft PhotoScan
Accurate Mapping and Viewing with PrecisionHawk
Drone2Map for ArcGIS by ESRI: An Open Source Drone Mapping Solution.

Guard Against Anti-Drop Kit

Assists in maintaining contact between the camera and stabilizer on the unmanned aircraft.

Multimedia editing software

Video editing software of high quality is required for post-production. Modern drones often record in Adobe DNG raw, which preserves all the picture data for editing.

Operating Systems In Drone Technology

A majority of unmanned aircraft run on Linux, while a small percentage on Microsoft Windows. In 2014, the Linux Foundation unveiled an initiative dubbed Dronecode.

The Dronecode Project is a community-driven, open-source initiative that consolidates and promotes other similar open-source UAV initiatives under the aegis of The Linux Foundation. As a consequence, UAVs may now operate on a standardized, open-source platform (UAV).

Protection against Hacking and Drones

Drones that can move through the air autonomously are a lot like mobile computers. They can be hacked since they have an OS, flight controllers, and main boards that all run on programmable code. Drones have been designed to scout for other drones, connect to their wireless network, and hijack them without alerting the owner. However, you may take some reasonable steps to safeguard your drone from cybercriminals.

Newest State-Of-The-Art Camera-equipped Drones

When it comes to both hobbyist and commercial drones, DJI is unrivaled. These are the most cutting-edge, patent-protected unmanned aerial vehicle drones currently available:

DJI Mavic Air 2 – The newest compact professional drone from DJI is the Mavic Air 2. Amazing high dynamic range media. Incredible Automatic Flight Modes and Obstacle Avoidance System (APAS)
Autel Evo 2 – The most recent model, the Autel Evo 2, offers a choice of three cameras: an 8k one, a 6k one, or a Dual 8k with FLIR infrared camera. Already in the works and available at retailers
Skydio 2 – Among the most capable tracking drones currently available
DJI Mavic Mini – The DJI Mavic Mini is the most capable little drone currently available. light at just 249 grams (8.78 ounces) and capable of 2.7k filming (2720 x 1530 @ 25/30 frames per second)
DJI Mavic 2 – The DJI Mavic 2 comes in two flavors, the Pro and the Zoom. They are both equipped with 4k cameras and feature 360-degree collision avoidance systems.
DJI Mavic 2 Enterprise (M2E) – Zoom or thermal imaging versions of the DJI Mavic 2 Enterprise (M2E) drone. Extras including a beacon, lighting, and a loudspeaker are included. Developed for use in rescue missions and similar situations
DJI Phantom 4 Pro V2.0 – DJI’s updated Phantom 4 Pro version 2.0 has “Vision” technology for avoiding obstacles. Drone has several uses, such as aerial photography, videography, and even photogrammetry at 4K resolution.
DJI Inspire 2 – Patented DJI Inspire 2 design and motors. Drone with many sensors for professional aerial imagery in 5k, as well as other resolutions, spectral ranges, and temperatures.
Yuneec Typhoon H Pro – Intel’s Realsense collision avoidance technology is included into the Yuneec Typhoon H Pro. Ideal for aerial filmmaking and photography by professionals.
Walkera Voyager 5 – Walkera’s newest drone, the Voyager 5, is an absolute marvel. Camera choices include thermal infrared, a low light night vision camera, and a powerful 30x optical zoom.
Walkera Vitus Starlight – Walkera’s newest little consumer drone, the Vitus Starlight, has a camera that can see in the dark and sensors that prevent it from crashing.
The DJI Matrice 600 – is a professional multirotor that can also be used as an aerial filmmaking platform, thanks to its seven available Zenmuse camera mounts.
DJI Matrice 200 Commercial Quadcopter – Dual batteries, inertial measurement unit, and satellite navigation systems for redundancy; this is the DJI Matrice 200 Commercial Quadcopter. The quadcopter may have two cameras attached to its underside (e.g thermal and zoom camera). Matrice 200 with a camera mounted on top makes bridge surveys a breeze. The Matrice 200 is equipped with a ToF laser, ultrasonic, and vision sensors for six-way collision avoidance.

FAQs: best answer what is drone technology or how does drone technology work

Q. What technology does drone use?

The IMU is a technology that can detect the current acceleration rate using one or more accelerometers. It does so by detecting changes in various rotational attributes using the gyroscope. These are technologies which enable the drone to move into the air and hover, or fly in any direction.

Q. What is the importance of drone technology?

The high-resolution cameras and sensors instilled in drones permit them to capture intricate details, more so in remote areas where human entry is not permissible. Drones can also detect and identify cracks and defective conditions, ensuring the public’s safety and welfare.

Q. What are the 4 types of drones?

Here’s a rundown of the four main types of drones, their uses, their strengths and weaknesses:

Multi-Rotor Drones.
Fixed-Wing Drones.
Single-Rotor Drones.
Fixed-Wing Hybrid VTOL.

Q. Who invented drone technology?

Abraham Karem was born in Baghdad, Iraq, to an Assyrian Jewish couple. His family moved to Israel in 1951, where he grew up. From an early age, he had an innate passion for aeronautics, and at the age of 14, he started building model aircraft. Karem is regarded as the founding father of UAV (drone) technology.

Q. Where are drones used?

Drone Technology History and Today’s Uses:

Aerial photography for journalism and film.
Express shipping and delivery.
Gathering information or supplying essentials for disaster management.
Thermal sensor drones for search and rescue operations.
Geographic mapping of inaccessible terrain and locations.

Q. How many types of drones are there?

There are four main physical types of professional drones: multi-rotor, fixed-wing, single-rotor helicopter, and fixed-wing hybrid VTOL. The different body styles of each type of drone contribute to the amount of weight they can carry (payload), efficiency and duration of the flight.

Q. Who is the leader in drone technology?

DJI: DJI is the global leader in manufacturing innovative drone and camera technology for commercial and recreational use. DJI was founded and run by people with a passion for remote-controlled helicopters and experts in flight-control technology and camera stabilization.

how does drone technology work

Q. What is the full form of drone?

An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board.