Antes de começarmos a nossa descrição de um sistema anti-drone, tenho duas perguntas:

A disadvantagens de RF deteção:

1. A encriptação do sinal é difícil de decifrar
2. Vulnerável a interferências electromagnéticas
3. O FPV é difícil de localizar

Deteção de radar

O que é radar de matriz faseada:

Phased-array radar is phase-controlled electronically scanned array radar. Its ability of fast and precise beam conversion enables the radar to complete the scanning of the whole space within 1 minute. The so-called phased array radar is a radar array composed of a large number of identical radiation elements. Each radiation element is independently controlled by the wave controller and phase shifter in phase and amplitude, which can obtain accurate and predictable radiation pattern and beam direction.

O radar anti-Uas detecta principalmente alvos "baixos e pequenos e lentos", utilizando frequentemente a banda X e Ku, e sintetiza a dupla polarização totalmente coerente, o processamento inteligente de dados de radar, a fusão de dados de várias fontes e outras tecnologias, que podem ser realizadas em todas as condições meteorológicas, activas, multi-alvo e deteção fina de "alvos baixos e pequenos e lentos" + alvos "micro-meteorológicos de baixa altitude".

O advantagens de rdeteção de adar:

1. Velocidade de varrimento rápida, feixe flexível e controlável
2. Longo alcance de deteção
3. A capacidade do alvo é grande e centenas de alvos podem ser monitorizados e seguidos simultaneamente no espaço aéreo
4. Forte capacidade anti-interferência
5. Forte adaptabilidade a um ambiente de objectivos complexos
6. Elevada fiabilidade

A disadvantagens de rdeteção de adar:

1. Custo elevado
2. O equipamento é complexo
3. Existem ângulos mortos a curta distância
4. O alcance do feixe de varrimento é limitado

Sistema de rastreio ótico de electrões (EOTS)

O que é o sistema de rastreio de ótica eletrónica:

O equipamento optoelectrónico de identificação e rastreio combina a tecnologia de imagem de luz visível e infravermelhos, recolhe a informação ótica do alvo através do sistema ótico e converte-a em sinais eléctricos para processamento e análise, de modo a realizar a identificação e o rastreio rápidos e precisos do alvo.

O advantagens de sistema de rastreio ótico de electrões:

1. Câmara de alta definição, alta precisão
2. Forte capacidade de reconhecimento de objectos
3. Transmissão de imagens em tempo real
4. Seguimento automático do alvo

A disadvantagens de sistema de rastreio ótico de electrões:

1. Afetado pelo ambiente
2. Sofisticação técnica
3. Forte dependência de hardware
4. As câmaras ópticas são mais caras

Sistema de contador

After detecting the drone through the detection system, it is necessary to solve the problem of how to defend the drone. The ways to defend Uavs are usually divided into two main categories, namely soft kill and hard kill. Soft kill is mainly achieved through electronic technology, while hard kill uses physical destruction. At present, the most common is soft-kill technology, because it is better cost performance and less difficult to implement. Soft kill technology applies electromagnetic wave technology to interfere with the remote control signal and video transmission signal of UAV by transmitting the same frequency signal. The technology was first used in drone jamming devices, and then spawned into drone spoofing devices.The market is flooded with drone jamming devices, and let’s discuss this one first. Then, let’s look at drone decoy devices.

Drone Jammer

O que é o bloqueador de drones:

Utilizando a tecnologia de ondas electromagnéticas de alta frequência, a onda electromagnética é transmitida na mesma banda de frequência que a banda de comunicação do UAV, o que interfere com a receção das instruções do UAV no telecomando, fazendo com que o UAV não consiga analisar normalmente as instruções e os sinais de vídeo no telecomando, perdendo assim o controlo e regressando ou aterrando de acordo com o procedimento predefinido.

Normalmente, classificamos os bloqueadores em várias categorias de acordo com a sua estrutura, nomeadamente bloqueadores fixos, bloqueadores de mochila e bloqueadores de mão. De seguida, apresento algumas imagens que correspondem a cada um destes tipos.

You need to decide which structure of the interference device to choose according to your specific use case.

O advantagens de bloqueador de drones:

1. O preço é barato. Desempenho de alto custo
2. Pode abranger várias bandas de frequência de comunicação
3. Bloqueio de vários alvos em simultâneo

A disadvantagens de bloqueador de drones:

1. A distância de interferência é limitada
2. Elevada potência do equipamento
3. Não é causado qualquer dano direto ao drone, que apenas pode forçar o drone a regressar ao seu ponto de partida ou a aterrar em segurança no local.

Drone Spoofer

O que é o drone spoofer:

Ao enviar sinais GPS enganadores, o drone não pode obter com exatidão informações sobre a sua posição, o que resulta num desvio do posicionamento ou na perda da capacidade de navegação.

O mercado é constituído principalmente por equipamento de falsificação estacionário e por equipamento de falsificação portátil. Não há grande diferença na estrutura do dispositivo de falsificação GNSS, o que nos deve preocupar é o facto de abranger os sinais de vários sistemas de posicionamento por satélite. Conhecemos a corrente principal dos quatro principais sistemas de posicionamento global: GPS, Beidou, Galileo, Glonass. Em geral, precisamos de sinais dos quatro sistemas. Como os Uavs comuns têm pelo menos dois localizadores GNSS, muitos dos Uavs da DJI, por exemplo, podem ter três ou até quatro localizadores. Por isso, para sermos infalíveis, é melhor que o nosso dispositivo de spoofing cubra os 4 principais GNSS.

O advantagens de drone spoofer:

1. Baixo consumo de energia do dispositivo
2. Pode afetar diretamente o voo do drone, ou mesmo provocar a sua queda.
3. A cobertura é maior do que a do jammer

A disadvantagens de drone spoofer:

1. O preço é relativamente mais caro do que o jammer
2. Incapaz de lidar com drones sem capacidades GNSS
3. Afecta a funcionalidade GNSS de todos os dispositivos na zona

How to Choose a Jammer

Currently, there are many different jammers on the market. However, according to the structure of the equipment, it can be divided into three categories, respectively, stationary jammer, backpack jammer, and handheld jammer. You need to choose the right type for different use cases. Stationary jammer used for installation in outdoor use, to establish a station defense area, can be used for a long time. However, backpack jammers and handheld jammers are usually used when performing temporary tasks and cannot be used for a long time, and the working time is limited by the battery life.  In addition, from the antenna of the interference device can be divided into omnidirectional interference and directional interference.  Under a specific design, directional jamming can also achieve 360° omnidirectional jamming. What you need to know is that the directional jamming distance will be better than the omnidirectional jamming distance. The advantage of omnidirectional jamming is that the signal is transmitted at 360°.  The above mainly analyzes the related characteristics of the jammer from the structure, and then I will introduce some key performances of the jammer from the technical point of view.

There are two key parameters here:

• Frequency(It refers to the frequency range of the interfering signal emitted by the device)
• Power(It refers to the power of the interfering signal transmitted by the device)

The operating frequency of the device is determined by the communication frequency of the drone. There are two links for UAV communication, one is the remote control signal link, and the other is the video transmission signal link. These two signal bands are the ultimate targets of jamming devices. Common UAV communication frequencies: 868M, 915M, 1.5G, 2.4G, 5.2G, 5.8G. To cope with interfering devices, some FPV use very rare signal bands, such as 1.2G and 3.3G. These frequencies are the frequencies that jamming devices need to use. 

Now let’s look at anther parameter – Power. Signal power is often related to our other important performance, which is the jamming distance. Obviously, the larger the power, the farther the signal travels. At present, common power values such as 10W, 20W, 50W, 100W. 20W is commonly used in jamming guns, 50W and 100W are commonly used in stationary jamming equipment. It might be different in practice, but it’s a common occurrence. Because the large power requirements for the power supply will be higher, will undoubtedly bring more volume and heavier weight. So, if you want more interference range, you need more signal power. In addition, different interference ranges are obtained by using omnidirectional and directional antennas.

In general, the signal gain of directional antennas is between 10 and 16db, while the gain of omnidirectional antennas is between 2 and 6db. But the beam Angle range of directional antennas is limited and may be less than 90°. However, the signal radiation of omnidirectional antenna is 360° in the horizontal direction. It’s more of a performance tradeoff, distance for Angle. From the energy point of view, it follows the conservation of energy. Of course, we can use technology to send directional signals in a 360° direction.

Omni-directional antenna beam

Directional antenna beam

By analyzing the above 2 key parameters, I think we can clearly understand what kind of jammer we need. For example, say you spot an unauthorized DJI drone within 500 meters and want to temporarily disrupt it. We can easily check that the communication frequency of DJI UAV is 2.4G and 5.8G, and 5.2G is also used in some areas. GPS positioning is often 1.5G. The jamming gun uses a directional jamming mode, and usually 20W of high-frequency signal power can effectively interfere to a distance of 500 to 1000 meters. So, all you need is a jamming gun containing 1.5G,2.4G,5.2G,5.8G, and 20W signal power for a single channel. It’s possible that the DJI drones in your area are not using the 5.2G frequency. You can also get rid of it, so you can save some money. This is the simplest example, but the reality is that it’s much more complicated, so most people choose to cover as much bands as possible. 

It is important to know that the interference distance described by many sellers is usually the limit distance determined by the ideal environment. However, in reality, the interference distance involves many factors, such as the natural environment, the electromagnetic environment, the fuselage direction of the UAV, the signal transmission route from the remote control to the UAV, and so on. Let’s look at the plot of the distance between the device signal and the drone and the distance between the remote control and the drone to understand the concept of interference distance more clearly.

At point Q, the strength of the drone signal and the device signal are equal, when the device is 1000 meters away from the drone. Within a distance of less than 1000 meters from D, the signal strength of the device is higher than that of the drone, that is, the signal of the drone is suppressed in this area. When D starts to increase, the device signal becomes weaker, while the distance between the drone and the remote control becomes closer, and the signal strength of the UAV is stronger. At this point, the drone signal cannot be suppressed and the drone cannot be interfered. If the departure point of the drone is farther away, the Q point position will move to the right, meaning that the device interference distance will increase. So usually the interference distance given is either a range or an extreme value.

By understanding the above, I believe you have been able to choose a suitable jamming device.