GNSS Interference in Wildlife

In this post, we collect the different types of GNSS interference that we detect around the world. We are going to update this post from time to time and possibly change the classification of interference in the future.

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We demonstrate only basic screenshots from our GP-Cloud software, such as spectrograms, power spectrum, spectrum waterfall, and basic parameters of GNSS signals.

If you are interested in accessing more detailed data please leave a message on the contact page.

GNSS Jamming

GNSS jammers vary in output power, modulation types, and spectrum width. Below we have collected and categorized the most popular jammers.

High-Quality Jammer

This is quite a rare beast. It’s really wideband – over 60 MHz. This particular sample is perfectly calibrated for center frequency and has pretty good spectrum flatness for that kind of device.

GNSS jammer - wide band - spectrogram - with comments

We caught him at a crossroads. Obviously, the jammer is installed in a car. This is evident from the smoothly increasing and decreasing power. In fact, 97% of all the jammers we have detected are installed in cars.

GNSS jammer - wide band - with comments

Note that GLONASS is suppressed even better than GPS and Galileo. You rarely see that. In most cases, GLONASS does not suffer so much, because the RF spectrum of most jammers is shifted towards GPS L1 1575.42 MHz.

Here is another example of a spectrogram of such a jammer:

High quality GNSS jammer spectrogram 2

Average Quality Jammers

Here we have collected medium-quality devices. We classified them this way because of the narrower frequency bandwidth. Nevertheless, the center frequency is not badly calibrated and in-band spectrum flatness is good. Such jammers usually do not block the reception of GLONASS signals.

GNSS Jammer with limited bandwidth spectrogram

Example of a signal with a more accurately adjusted center frequency:

medium quality GNSS jammer

Low Quality Jammers

In this section, we placed jammers with a poorly defined center frequency and bad spectrum flatness.

Low quality GNSS jammer spectrogram
Low quality GNSS jammer

An example of a jammer signal with a really bad spectrum flatness:

Low quality GNSS jammer

Signal with narrow bandwidth and poorly defined center frequency:

Low speed FSK GNSS jammer

Worst-Performing Jammers

This section holds jammers with a purely sinusoidal signal, and simple pulse modulation.

The spectrum looks like this:

A jammer with a sine wave signal in a fast approaching car

Such jammers suppress only the GPS and Galileo. We caught this signal from a fast moving car:

A jammer with a sine wave signal in a fast approaching car raw gnss data

Here is an example of a jammer with a large frequency error:

Sin wave GPS jammer with 1566 MHz central frequency

The 90-second interval of sine wave interference with 1600 MHz center frequency. Only the GLONASS was affected:

Low quality in-car jammer 1600
Low quality in-car jammer 1600 spectrum

Long-Term Jamming Incidents

Most jamming incidents are very short. Cars arrive and leave quickly. However, this is not the case if you have a GNSS receiver located near a commercial vehicle parking area. This two-hour long incident we detected not far from a store. The driver did not turn off the jammer while unloading goods.

Learn more here about in-car jammers:

long-term GNSS jammer

Military Grade Jamming

Here we have compiled a collection of interference that we believe was generated by government authorities, rather than private players.

An example of GLONASS signal suppression. The equipment is not of high quality, as a significant drift of the central frequency over time is clearly visible.

GLONASS only jamming wideband interference

The signal is quite wideband. Some kind of spread spectrum modulation is obviously applied.

GLONASS only jamming wideband interference spectrum

Here is an example of a combination of GLONASS and GPS interference:

GPS + GLO jamming wideband interference

Wideband interference in the GLONASS band and a frequency-modulated signal in the GPS L1 band.

FSK GNSS jammer + Glonass noise modulated

GNSS Spoofing

We encounter GNSS spoofing all over the world with different attack scenarios intended for different missions.

GNSS Spoofer in Anti-Drone Systems

This is the most common application of GNSS spoofing. The anti-drone system simulates the coordinates of the nearest airport. The commercial drone is either landing or trying to fly to the takeoff point.

There are different usage scenarios here. Sometimes only GPS is spoofed, and the other constellations are blocked. Sometimes GLONASS + GPS are spoofed.

There are also different scenarios in terms of the duration of use. Automatic systems generate a fake signal within minutes. Sometimes a spoofer is activated for many hours.

Short-Term GPS + GLO Spoofing

In the images below you find three episodes with short durations. The attack scenario is non-coherent.

GPS + GLO spoofing anti-drone system
GPS + GLO spoofing anti-drone system satellites

Long-Term GPS + GLO Spoofing

We have encountered prolonged spoofing scenarios in countries with difficult political environments and during military activities. Below are screenshots of three incidents with a total duration of more than 30 hours during two days.

long-term GPS+GLONASS spoofing

Non-coherent Spoofing

During a non-coherent or otherwise asynchronous spoofing, the GNSS signal is generated with false coordinates, time, and other parameters. If the receiver already acquires real signals, a non-coherent signal is perceived as noise. Therefore, for a successful attack, it is necessary to force a receiver to lose track of the real signals. This can be done in a number of ways. You can learn more about attack scenarios here:

Here below you see an incident that lasted a few minutes. Our system detected GPS spoofing with 100% probability. The interference power was quite high, 15 dB higher than the system’s noise level. The signal is clearly visible on the spectral waterfall. Since the center frequency of GPS L1 and Galileo L1 coincide, the reception of Galileo signals slightly suffered.

Non-coherent GPS spoofing

A distinctive sign of a non-coherent attack is the presence of signals with a huge residual and high SNR:

Non-coherent GPS spoofing fake signals

Signal spectrogram:

Non-coherent GPS spoofing spectrum

Сoherent Spoofing

Coherent spoofing is always intentional! The attacker needs to know the coordinates of your GNSS antenna precisely enough to simulate a signal completely identical in all parameters to the real one. Watch the video at the link to learn more about coherent attack:

Below you see an example of intentional coherent spoofing that our system detected. Spoofing started with a low power signal, which gradually increased until the signals of real GPS satellites were completely overlapped. Then an attempt to shift the coordinates.

Coherent Intentional GNSS Spoofing
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