Technical articles - let you understand the mysteries of drones

Speaking of drones, everyone must be very familiar with them. With their cool appearance and practical functions, drones have developed rapidly in recent years and have been welcomed by people.

I often see it around me.

In fact, after entering the 5G era, drone technology will have another leap forward. With the support of 5G, the performance and application scenarios of drones will also be greatly upgraded.

In today's article, Xiaozao will talk to you about what changes 5G will bring to the drone industry and what direction drones will develop in the future.

    Traditional drones    

First, let’s start with traditional drones.

Drone is actually the abbreviation of Unmanned Aerial Vehicle (UAV). More precisely, a drone is an aircraft that uses wireless remote control or program control to perform specific aviation tasks. The biggest difference between it and a conventional aircraft is, of course, whether there are people on board the aircraft.

Some people also say that a drone is a flying robot.

The history of drones is actually not short. As early as 100 years ago during the First World War, the world's first drone appeared.

The earliest drones

In the long years that followed, drones have been used for military purposes, such as target drones, reconnaissance aircraft, etc.

The old American "Firebee" target drone

Entering the 21st century, military drones have developed to an astonishing degree, becoming the protagonist on the battlefield and the focus of the public.

The famous American MQ-9 Reaper drone is proficient in reconnaissance and strike

As drone technology continues to mature, it has begun to develop into the civilian field, spawning a variety of civilian models and applications.

These civilian drones are of various types, with distinct features and a wide range of uses.

According to the flight platform configuration, it can be divided into fixed-wing UAVs, rotorcraft UAVs, flapping-wing UAVs, paraglider UAVs and unmanned airships.

Among the above-mentioned drones, the one we have seen most often is the civilian rotor drone shown below.

This type of drone is currently widely used in various social fields, such as drone spraying of pesticides, drone logistics, drone filming, drone light shows, and so on.

Drone spraying of pesticides

    Connected drones   

The fuselage of a civil rotorcraft UAV is usually composed of the following parts: frame, power system, flight control system, and mounting system.

The rotor, motor, and battery in the frame are all part of the power system.

In addition to the fuselage, there is also a ground control system.

like this:

This control method belongs to point-to-point communication. The data transmission between the remote controller and the drone is done by Wi-Fi or Bluetooth.

As we all know, the communication distance of Wi-Fi or Bluetooth is very limited. Take Wi-Fi as an example, it can usually only be controlled within the line-of-sight range of 300~500 meters (under certain conditions, it can reach more than 1 kilometer). Not to mention Bluetooth.

Therefore, this method greatly restricts the flight range of the drone.

As a drone operator (usually called a "pilot"), you usually don't dare to let the drone fly too far. If it flies too far, it may cause the communication between the drone and the pilot to be interrupted, or even "crash". So people came up with a new way of drone communication, that is - networked drones.

Networked drones actually use cellular communication networks to connect and control drones. In simpler terms, it uses base stations to network drones.

Drone + Cellular Communication Base Station

Compared with Wi-Fi, cellular base stations have a wider coverage area, which will make drone communications more flexible and reliable.

If you know a little about drones, you must have heard of the two terms "image transmission" and "digital transmission".

"Image transmission" means transmitting images, that is, transmitting the video or image pictures taken by the drone's pod camera back to the ground.

Camera pod for drone

"Digital transmission" means transmitting data. There are a lot of sensor data and flight data on the drone, and transmitting this data back to the ground is digital transmission.

There are three main purposes of communication between drones and the ground: image transmission, data transmission and remote control.

Image transmission has the highest requirements for drone communication capabilities.

If we use Wi-Fi point-to-point communication, the communication distance is generally no more than 500 meters*, and the image transmission capability can reach 1080p (resolution 1920×1080, ultra-clear), about 30 frames per second. *Competent manufacturers such as DJI have developed their own OcuSync image transmission technology (similar to Wi-Fi, also using the 2.4GHz frequency band), claiming that the image transmission distance can reach 7 kilometers (1080p).

If you use a networked drone, 4G LTE cellular communication technology, when the network base station coverage is in place, it can be said that there is no distance limit in theory. As for the image transmission capability, it is currently mainly around 720p (resolution 1280×720).

Images transmitted from drones

If it is drone aerial photography, due to the long distance, the 720p or 1080p resolution is not clear enough, and it still cannot meet the needs of users in some specific scenarios (such as checking device indicator lights, parameters, and face recognition).

In addition to speed and bandwidth, let's look at other aspects.

In terms of positioning, the existing 4G network has an airspace positioning accuracy of about tens of meters (if GPS positioning is used, the accuracy is about meters). In some applications that require higher positioning accuracy (such as campus logistics distribution, complex terrain navigation, etc.), it is necessary to consider adding base stations to provide assistance in order to achieve this.

In terms of airspace coverage, 4G networks can only cover applications within an airspace of 120 meters or less. Above 120 meters (some high-altitude needs, such as high-altitude mapping, trunk logistics, etc.), drones are prone to loss of connection.

In summary, the current application scenarios of drones under 4G networks and Wi-Fi networks are too limited and the user audience is too small, which makes it difficult for them to be popularized in the consumer market and also restricts their long-term development and value realization.

    5G drones    

Ding ding ding! Our 5G finally makes its debut!

Because 4G and Wi-Fi are not powerful enough, we need a more powerful cellular communication technology, which is 5G.

What exactly will 5G bring to drones? Let’s take a look at them one by one.

First of all, let’s talk about image transmission.

The first of 5G’s many features is, of course, ultra-wideband.

The theoretical bandwidth of 5G can reach more than 20Gbps. The experimental networks that have been built so far have generally reached a rate of 1Gbps, which is more than ten times the speed of 4G LTE.

With the support of this rate, not to mention 720p and 1080P, even 4K and even 8K ultra-high-definition videos can be perfectly supported.

Compared with the static, low-latitude perspective of traditional ground cameras, drones combined with 5G will achieve a dynamic, high-latitude, ultra-high-definition wide-angle bird's-eye view, which is an ultra-high-definition "God's perspective."

Drone aerial photography

What’s more amazing is that compared to traditional drones that can only shoot with a single-lens camera, with the support of 5G, drones can be equipped with 360° panoramic cameras for multi-dimensional shooting.

VR Panoramic Camera Pod

People on the ground can freely view the situation from all angles through VR glasses.

In other words, drones have truly become the "eyes in the sky", with very clear and unobstructed views.

Bandwidth alone is certainly not enough.

5G networks also have the characteristics of ultra-low latency, which can provide millisecond-level transmission latency (less than 20ms, even up to 1ms, while 4G LTE is more than 50ms). This will enable drones to respond to ground commands faster and ground pilots to control drones more accurately.

5G can also provide centimeter-level positioning accuracy, far exceeding the ten-meter level of LTE and the meter level of GPS. In this way, it can fully meet the flight needs in complex terrain environments such as urban areas.

The Massive MIMO antenna array and beamforming technology used by 5G can flexibly and automatically adjust the phase of the signal transmitted by each antenna, not only in the horizontal direction but also in the vertical direction.

3D-Beamforming

This will be conducive to signal coverage of targets at a certain altitude, meet the country's requirements for low-altitude airspace supervision within 500 meters, and meet the future demand for drones to fly above 120 meters in cities with many high-rise buildings.

In terms of drone flight data security, 5G also has obvious advantages over 4G or Wi-Fi. The 5G data transmission process is more secure and reliable, and the wireless channel is not easily interfered with or invaded.

In addition to solving the problem of communication capabilities between drones and base stations, 5G also brings great improvements to the drone system support platform.

A complete UAV system consists of an air segment and a ground segment.

In traditional Wi-Fi point-to-point communication, the ground part only has the remote control and the mobile phone, and its capabilities are very limited.

The networked drone can provide powerful platform support:

Combined with cloud computing, the ground platform of networked drones can provide larger data storage capacity and more powerful computing power, providing services (such as video viewing) to more ground personnel in remote locations.

Thanks to 5G's massive connectivity features, the number of drones that can be connected to the 5G network is almost unlimited (1 million terminals can be connected per square kilometer).

5G's edge computing capabilities also have their place. An edge computing center can be set up near a 5G base station, and drone-related data can be calculated at the edge computing center instead of being sent to a more distant cloud computing center, thus ensuring low latency (serving autonomous driving of drones in the future).

Even more, the D2D (Device to Device) communication capability provided by 5G can enable direct communication between drones, better serving autonomous driving and swarm collaboration.

D2D Communication

In short, the high bandwidth, low latency, high precision, wide airspace, and high security provided by 5G can help drones make up for their shortcomings, unlock more application scenarios, and meet more user needs.