Counter-UAS Science: Radio Detection Systems

I,Overview

        In this paper, the terms "UAV", "low-small-slow", "low-slow-small", and "rotary-wing UAV" are all used to refer to consumer rotary-wing low-altitude aerial vehicles, as opposed to military high-altitude, high-mobility aerial vehicles.These refer to consumer rotary-wing low-altitude vehicles, which are different from military high-altitude, high-mobility vehicles.At present, in the field of security control for low-altitude rotary-wing aircraft, the most widely used should be the radio detection system, and the industry is often called other names such as "passive radar", "radio listening equipment", "electromagnetic wave detection system", "electromagnetic wave detection system", "electromagnetic wave detection system", "electromagnetic wave detection system", "electromagnetic wave detection system", "electromagnetic wave detection system", "electromagnetic wave detection system".Electromagnetic wave detection system", "spectrum detection system", in this article all refer to the same product.Radio detection systems are generally composed of a data processing host plus a number of antennas in various forms.The main working principle is to receive electromagnetic waves in the air and detect whether there is a communication signal between the rotary-wing UAV and the remote control to determine whether there is a target in the defense zone.

Second, the principle of technology

        As most of the rotary wing UAVs always maintain wireless communication with the remote control during flight, they continuously transmit radio waves in all directions in the air, which are generally distinguished into remote control signals and map transmission signals according to the type of data, i.e., a series of control instructions sent by the remote control to the vehicle or a series of state parameters sent back by the vehicle, which are generally discontinuous and not regularly followed.This kind of signal is generally discontinuous and not regular.Graphic signals, on the other hand, are signals that the vehicle continuously transmits video streams captured by its own camera to the remote controller, which are continuous and have more distinctive signal characteristics.

        Mainstream commercial drones use certain radio frequency bands in accordance with international standards, and the current stage of development of the technology allows the coding method to have a certain pattern that can be analyzed. Therefore, when professional radio detection equipment receives a specific radio signal, it can quickly detect most of the mainstream drones in the defense zone according to the above characteristics.

        This kind of equipment has very many advantages, due to the smaller volume limit, can use more advanced antenna than the drone bigger, detection distance is far, according to the user's site environment requirements defense range ranging from 1 to 10 km, and the fastest in the drone or the remote control can detect the target of the moment of power on, the early warning of the timeliness of the very good, and the price is relatively inexpensive, the use of the more widely.

        The detection system is composed of radio modules, each module can only cover a certain radio frequency band, conventional radio detection system manufacturers in order to maintain the cost advantage, usually in the common two drone frequency band 2.4GHz and 5.8GHz detection, give up the other relatively cold radio frequency band, this strategy solves the vast majority of drone aerial photography enthusiasts unintentionally brought the intrusion of the threat of confidentiality.This strategy solves the intrusion or confidentiality threat unintentionally posed by most drone aerial photographers.

        If you encounter some counter-surveillance capabilities of the ulterior motive, after modification, the drone remote control signals and mapping signals into a relatively cold band, the user needs to use a wider coverage, more technologically advanced equipment for detection, such as the use of more modules, or wider bandwidth of the product.Our company can provide users with up to 8 frequency bands detection system, covering most of the frequency points between 70MHz~6GHz radio frequency band, effectively protect the security of highly sensitive areas.

Third, product features

Radio detection system is a passive receiving detection system, itself does not emit any electromagnetic wave signals, the surrounding electromagnetic environment does not have an impact, very efficient and safe.Due to the absence of mechanical moving parts, the user 24 hours a day, 7 * 24 hours running on the service life of the impact is not great.Through the technical means of targeted extraction of a specific code of the radio signal, can be very accurate to determine the existence of the target, the real target and interference signals to distinguish between the stronger technical strength of the manufacturers, but also through the radio to identify the body of the UAV code targeted distinction between a number of different drones, pre-recorded "white listThe pre-recorded "whitelist" can screen their own drones as well as "black flight" drones, so as to achieve the purpose of realizing effective airspace security without affecting the normal operation of drones.

Deficiencies of the radio detection system

        The passive reception characteristic of the radio detection system has also become a deficiency in special scenarios.Modern UAVs are equipped with very advanced positioning functions, which can be used to carry out high-precision positioning through GPS, GLONASS and China's Beidou system, and have the functions of waypoint flight and fixed-point flight.If a person with ulterior motives carries out destructive activities or illegal behaviors through this function, the entire process does not use manual remote control, only through the preset instructions to the designated location or according to the designated trajectory of the flight, the flight does not emit any electromagnetic wave, the drone is in the state of radio silence, then the radio detection system is unable to detect the drone, the early-warning function will not work.

V. Scenario Analysis of Radio Detection Systems

        Since China is a big country of consumer rotary-wing drones, drone users are very common, and some drone users lack safety awareness, do not know how to report the flight plan to the official in advance, and the no-fly zone labeling in the flight APP is not comprehensive enough, so they unintentionally invade the sensitive and high-risk area in aerial photography, or they know that it is a warning area, but do not know the seriousness of the consequences, and fly into it because of their curiosity.The following are some of the reasons why you should not fly into these areas

        Even if they belong to the "black flight", they will not deliberately hide their whereabouts, the protected area such as the installation of a radio detection system will be effective in detecting the presence of drones in the nearby airspace, and timely safety warnings will be given to the management personnel in the key areas to dissuade the drone users from the area.Key scenarios such as party, government and military core protection areas, major security activities, key energy protection areas, prisons and detention centers, land bordering ports anti-smuggling and so on, are all for radio detection systems to play an important role in the arena.