Increasing the protection of reconnaissance UAVs from FPV interceptors
Aircraft-type reconnaissance UAVs are one of the most important elements of reconnaissance and strike circuits (RSC) in the area of a special military operation (SVO). It is from aircraft-type reconnaissance UAVs that all other RSC elements often receive target designation – aviation, artillery, multiple launch rocket systems (MLRS), operational-tactical missile complexes (OTRK) and FPV operatorsdrones.
Aircraft-type reconnaissance UAVs have a fairly long range and flight duration, and their small size, combined with the frequently used “wing” type design, makes them relatively invisible to enemy radar stations.
However, low-visibility does not mean invisible. Presumably, aircraft-type reconnaissance UAVs are well detected by Israeli RADA radars, and the presence of a two-way control channel allows them to be detected using electronic intelligence (EI) systems. And while enemy radars can be detected by their radiation and destroyed by anti-radar missiles (ARM) or other means of destruction, it is practically impossible to detect EI systems operating in passive mode.
RADA radar somewhere in Ukraine
Using anti-aircraft missile systems (SAM) to destroy aircraft-type reconnaissance UAVs is not very effective both due to the high cost and shortage of anti-aircraft guided missiles (SAM) on the part of the enemy, and due to the risk of destroying the SAMs themselves. At the same time, the flight altitude of aircraft-type reconnaissance UAVs makes them invulnerable to small arms and cannon weapons.
Modern Western air defense systems with their expensive SAMs are not very effective in hunting Russian aircraft-type reconnaissance UAVs
It would seem that the eye sees, but the tooth does not feel?
However, the enemy has found a solution – the destruction of aircraft-type reconnaissance UAVs is ensured by FPV drone interceptors. According to open data, the enemy has already destroyed dozens, if not hundreds, of Russian aircraft-type reconnaissance UAVs using FPV interceptors.
Russian specialists took countermeasures, for example, reconnaissance UAVs were equipped with means of detecting FPV drones - when they approach, an evasive maneuver is automatically performed with a change in altitude and direction of flight. The range and flight time of FPV drones at high altitudes are limited, so theoretically a reconnaissance UAV can evade until the enemy runs out of batteries.
However, passive measures alone are not enough – aircraft-type reconnaissance UAVs pose an existential threat to the enemy’s defense, so he will attack regardless of the losses of FPV drones, and the cost of FPV interceptors is an order of magnitude less than the cost of reconnaissance UAVs.
Stills from video of successful and unsuccessful attacks by Ukrainian FPV interceptors on Russian fixed-wing reconnaissance UAVs
Given the above, there is an objective need to increase the security of aircraft-type reconnaissance UAVs from attacks by enemy FPV interceptors, which is what we will talk about today.
Presumably, the most effective way to increase the protection of aircraft-type reconnaissance UAVs from FPV drones may be to equip them with an onboard defense system, but first the approaching enemy FPV interceptor must be detected.
Drone detector
Judging by the implementation of automated evasion of Russian aircraft-type reconnaissance UAVs from FPV interceptor attacks, this task has already been solved by installing drone detectors, most likely detecting the video transmission channel.
Since it is impossible to implement control of FPV interceptors via fiber optics, and the Starlink communication terminal for an FPV drone is too large and expensive, the enemy will not be able to get rid of the outgoing video signal.
Drone Detector Hawk V8
At the same time, at present In the US and other leading countries of the world, low-orbit satellites are being created and deployed that provide communication even with smartphones that support 5G communication technology, while the data transfer speed will potentially allow them to be used to transmit video signals and control commands, and the cost and size characteristics of such terminals (in the dimensions of a smartphone) will allow them to be placed even on FPV drones - this must be taken into account.
Once the approach of an FPV interceptor has been detected, its exact location must be determined.
Thermal imager/camera
If you watch the video recordings of attacks by Ukrainian FPV interceptors on our reconnaissance aircraft-type UAVs, these attacks are always or almost always carried out from a top-down position. Accordingly, to accurately detect the location of the attacking FPV interceptor in the upper part of the reconnaissance aircraft-type UAV, it is necessary to install a bundle of a daytime video camera and a thermal imager in the tail section of the UAV.
Considering that the FPV interceptor will be detected at a fairly close distance, we will not need a bulky optical-electronic station (OES), that is, approximately the same models as those installed on FPV drones can be installed.
Thermal and video cameras for FPV drones can be quite compact
Ideally, a reconnaissance UAV should include an automatic recognition and tracking unit - this would significantly simplify the use and increase the efficiency of the suppression subsystem. Various Russian manufacturers of FPV drones are currently testing and even already using target acquisition systems, especially for ground targets, which is much more difficult than detecting contrasting targets against the sky.
Suppression subsystem
Of course, ideally we would like to ensure the complete destruction of the enemy's attacking FPV interceptors, but it is far from certain that it will be possible to place any small arms or projectile systems on small-sized aircraft-type UAVs.
Functional jamming is not a guaranteed way to disable attacking FPV interceptors, but it can significantly increase the chances of reconnaissance UAVs to disrupt an enemy attack, while, as we have already discussed above, the range and flight time of FPV drones at high altitudes are limited.
Potentially, powerful laser emitters based on solid-state laser diodes of blue and infrared (IR) spectrum, which are currently widely used in various household appliances and tools, can be used in the suppression subsystem. The power of blue laser diodes with a wavelength of 445 nm, used in projectors, reaches 8 W, the power of IR laser diodes with a wavelength of 808 nm, used in engraving machines and machines for cutting various materials, can reach 10 W.
The basic composition of the functional suppression subsystem can use both of the above-mentioned diodes at once, with individual focusing lenses and a single guidance drive in the horizontal and vertical planes. Or, based on the test results, it is possible to focus on one type of laser.
NICHIA NUBM47A1 8W 445nm laser diode and Hangzhou Technology TO808DL10 10W 808nm laser diodes (not to scale)
It can be assumed that the mass of the suppression subsystem, made in an aluminum case (to ensure heat dissipation), will be several hundred grams. The efficiency of laser diodes is about 30-40%, i.e. the total power consumption of the suppression subsystem will be about 50 W during active work on enemy FPV interceptors.
In fiber optic assemblies, the output power of blue and IR diodes can be tens of watts.
40W 445nm, 30W 808nm and 30W 966-986nm lasers
Here it is necessary to make a remark - in open sources various bloggers conducted experiments on defeating household IP cameras using blue laser pointers of 445 nm with a real output power of about 1 W. At the same time, the CCD matrices of such cameras showed high resistance to laser radiation - as a result of exposure to laser radiation from a distance of several meters for several tens of seconds, only minor damage remained on the CCD matrix in the form of a certain number of burnt pixels.
In our case, the radiation power can be an order of magnitude higher, but due to the fact that both the protected reconnaissance UAV and the attacking FPV interceptor are mobile - they change their flight path and oscillate due to the influence of atmospheric turbulence, the time of continuous exposure of radiation to the matrix of the video camera and thermal imager of the attacking FPV drone will be significantly less. Therefore, it will be possible to understand whether the lasers of the suppression subsystem will damage the enemy's cameras only experimentally.
Second operator
There is a possibility that automated laser beam guidance will be ineffective, in which case laser guidance to FPV interceptors can be done manually, well, once on combat aircraft it was considered normal to have a gunner-operator of defensive weapons, perhaps the time has come for collective control of reconnaissance UAVs - in fact, in addition to the pilot-operator, we add a gunner-operator to the crew of an aircraft-type reconnaissance UAV.
Something like this, but remotely
It can be assumed that the transmission of UAV control commands and commands for controlling the suppression subsystem will be able to proceed in parallel without problems. As for the video signal, everything depends on the channel width - either this will also not cause problems, or it is possible to reduce the quality (resolution and frame rate) of the main video signal, giving priority to the video signal from the onboard defense system at the time of attack.
Conclusions
Does the proposed UAV onboard defense system remind you of anything?
In fact, something similar already exists – this is the Russian airborne defense system L-370 “Vitebsk” / “President-S”, designed for installation on airplanes and helicopters, providing suppression of optical homing heads of attacking air-to-air missiles and SAMs in a similar way, in a fully automatic mode.
L-370 "Vitebsk"
In essence, the proposed onboard UAV defense system is a kind of conditional simplified analogue of the Vitebsk/President-S complex, but made on the basis of commercially available components.
Will the enemy be able to protect FPV interceptors from laser beam blinding?
Theoretically, there are filters for a selected wavelength, that is, you can install such filters on a daytime video camera, but in reality everything is not so simple - a weak, thin filter will still let through most of the radiation, for example, protective glasses for certain wavelengths protect only from reflected laser radiation, and a direct hit of laser radiation with a power of several watts is guaranteed to damage your eyesight, which everyone can see for themselves, albeit only twice. If you install several filters, then nothing will be visible through them even without any laser illumination.
Installing any protective filters on a thermal imager will most likely not work at all, since it has special germanium or chalcogenide glass that is transparent in the IR range, and any other glass or plastic will completely block the thermal image, and in general, the thermal imager will most likely fail due to exposure to an IR laser.
It cannot be said that the proposed onboard UAV defense system will allow them to be 100% protected from attacks by FPV interceptors - the enemy will use them in groups, trying to attack simultaneously from different directions, but such is the continuous war of the "sword and shield".
Nevertheless, it can be assumed that, in combination with active maneuvering, the use of laser onboard defense systems for reconnaissance UAVs of the aircraft type will significantly increase their survivability on the battlefield, ensuring stable and highly effective operation of the reconnaissance and strike contours of the RF Armed Forces.
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