//Drone Detection FAQs

Drone Detection FAQs

What is the distance/accuracy of RFeye systems when locating a drone or controller?2020-08-20T14:04:49+00:00

The answer to this is both simple and complex. The simple answer is +/- a few meters – in perfect conditions. The longer answer should take into account all these conditions: quality of the timing source, relative spacing of the receivers, the signal parameters and any impacts of the terrain. For more information on each of these factors, see our webinars “The Anatomy of an Effective Counter Drone Solution” and “TDOA – A Modern Geolocation Solution” and the CRFS white paper “Principles of Geolocation Techniques

What is the maximum lateral range of a standard off the shelf drone detection system?2020-08-20T14:03:23+00:00

This is dependant on the transmitter of interest. As we covered in the webinar “The Anatomy of an Effective Counter Drone Solution“, a COTS device has cheap chipsets and transponders and can work over 1-4 km. Military systems are built to run over 100s of km. The CRFS solution has an amazing sensitivity and will detect and track over even wider distance than that.

What’s the minimum pulse length you can geolocate?2020-08-20T14:03:23+00:00

The receivers can sweep at speeds above 350Gsamples/second, so are capable of detecting pulses of just 9 nanoseconds.

How many TDOA sensors are needed to get the location?2020-08-20T14:03:23+00:00

For a 2D geolocation on the ground, 3 receivers, but for drone detection purposes, where we need 3D geolocation, 4 receivers. More details of the theory behind this are available in the webinar “TDOA – A Modern Geolocation Solution” and the white paper “Passive Geolocation with 3D TDOA

Is 100 meters the lowest height of detection?2020-08-20T14:03:23+00:00

CRFS systems are capable of detecting drones and/or controllers down to ground level

2.4 and 5.8 GHz ISM bands are used by other devices – can you distinguish an authorized drone from another unauthorized drone?2020-08-20T14:03:23+00:00

Yes if we have some differentiating feature of an authorised drone. CRFS advocate a long term system of drone registration and allocation of specific airspace. With use of micro ADSB transponder you can easily create white and blacklists. With allocated airspace, one can simply use geofencing (in 3 dimensions) to also determine correct use of airspace.

What if the link between the drone and the operator is encrypted?2020-08-20T14:03:23+00:00

For CRFS, this is no problem. We are basing our detection, gelocation and tracking on the energy signature. The encoding does not impact us.

Are we blind if the UAV is flying purely by pre-programmed flight plan towards the object we protect?2020-08-20T14:03:22+00:00

If there are no RF emanations, we have nothing to detect against and hence geolocate and track. Hence why CRFS advocate a multi sensory approach in a cUAS system. However, this situation is extremely unusual. The hobby flyer usually has their FPV on. Even a bad actor wants video for target acquisition/identification or even propaganda purposes.

Can we hunt down cross border illegal RF signal sources?2020-08-20T14:03:22+00:00

Yes, very easily. We have many clients who operate multi sensory border control systems that incorporate CRFS capability as a critical element – for more information see www.crfs.com/applicationstory/border-security/ or contact us.

Do you have or are you considering space-based solutions?2020-08-20T14:03:22+00:00

We are currently working with a number of vendors looking to place our RF component into a LEO deployment.

Doesn’t micro ADS-B only work if you have cooperative ‘Bad Guys’?2020-08-20T14:03:22+00:00

If you have micro ADS-B in place, you can easily correlate geolocated signals to an ADS-B whitelist. Anything which does not have a corresponding ADS-B record can be considered as blacklist.

What kind of GPS notch filter do you use to protect your receiver in a GPS jammed environment?2020-08-20T14:03:22+00:00

We utilise an advanced GPS chip set which constantly measures quality of signal, plus looks for any spoofing. If that is activated we cross over from received GPS to internal timing. The internal timing works by training on GPS when present and then provides accurate sync for up to 9 hours. Hence our systems carry on being able to both detect and perform the TDOA correlation.

How good is this solution for drone protection at airports?2020-08-20T14:03:22+00:00

Airports are one of the primary areas of deployment for CRFS systems. The RF receivers can be used for a wide range of other activities (spectrum monitoring, interference detection) in addition to drone detection

Can each detector only be configured to look for a specific frequency of interest? What if the user is looking to scan a range of frequencies?2020-08-20T14:03:22+00:00

The detector can be set with a narrow frequency range or an extremely wide one, according to user requirements and the specific threat vectors.

Can these systems detect control signals sent to drones from cell phones?2020-08-20T16:11:51+00:00

Yes, CRFS receivers can detect and locate signals sent to and from cell phones. Of course, all mobile handset signals on the ground will look the same, so further information will be required to determine which is the controller (for example, it might be in a controlled area). For the drone, on the other hand, the altitude reading will tell you that you have an issue (unless it’s a bird carrying a phone!)

How do sensors send data back to the command center?2020-08-20T14:03:22+00:00

The CRFS received is designed to work with a range of transport media (native ethernet (optical and copper), plus USB means the other options are limitless). More importantly we have designed the system to work in very constrained backhaul environments. Remember that a lot of processing happens at the receiver and we simply port back the data required for the centralised processing. Typical Tx speeds when performing TDOA are around 200-300kbps. We believe we can reduce that if needed.

Can your receiver provide the frequency hop track of an FHSS uplink?2020-08-20T14:03:22+00:00

Yes, we can do that very easily. The demonstration in the “Anatomy of an Effective Counter Drone Solution” webinar shows that it is straightforward to measure the raster pattern and other parameters

For custom-made drones using COTS RF chipsets, what frequencies other than the ISM bands are of interest?2020-08-20T14:03:21+00:00

A wide range of frequencies could be used, hence the need for a wideband receiver. Common non-ISM bands include 4.2 GHz, 833 MHz and 433 MHz. CRFS’s automated detectors ensure that signals anywhere across this range can be detected

Can you speculate on how the CRFS receiver detections can be used by a C-UAS jammer?2020-08-20T14:03:21+00:00

CRFS systems make positive detections, and then geolocate and track drones in 3D. This can then be used to cue the required C-UAS measure (jamming, kinetic etc)

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