Field Report: Dronesense, a spectrum-scanning jammer and controller for drones.


by Lime Microsystems

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View all updatesJul 17, 2019

Field Report: Dronesense, a spectrum-scanning jammer and controller for drones.

by Ogün Levent

We’ve come a long way…

The Dronesense project is a spectrum-scanning jamming and ground control communication system based on LimeSDR. It started when I was a senior in University. My graduation project involved drones, and, as I got more familiar with the technology, I started to realize how easily drones could be used by individuals with bad intentions. I started researching what sorts of countermeasures existed and soon discovered ground-based, anti-drone rifles. These are equipped with a scope for visually detecting drones and a directional antenna for then jamming their signal (allegedly up to 1200 meters away).

My research soon revealed that there was a problem with the detection part of this type of countermeasure, it’s dependant on human vision. In the course of further research on drone detection, I discovered Software-Defined Radio and I had an idea: if I could make a unit that could detect drone remote control signals, there would be no need to rely on fault-prone human vision.

As a junior engineer, I decided to set myself a challenge and design a communication system that provides detection, jamming, and communication functions all together. I was familiar with the Arducopter, digital signal processing, and the MAVLink comms protocol, so I used that knowledge to get a government grant to work on the project. With that help, I was able to build a team and develop a fully functioning prototype system in one year.

The hardware side of the system consists of two parts: the drone and the base station (ground control). For the drone, we used a custom-made S600 frame with T-Motor U3 motors and a 40A esc. speed controller. The takeoff weight of the drone was 5 kg, flight time approximately seven minutes. The drone was also equipped with two LimeSDRs, one Advantech SBC a 4 W 2.4 G jammer, a U-Blox GPS module, a Pixhawk flight controller, and custom-made 433 MHz and 2.4 G antennas (which were unfortunately broken during testing).

Our drone

Dual LimeSDRs

Control Diagram

For the drone’s software, we combined two GNURadio OOT (out of tree) modules called gr-uaslink and gr-inspector. Initially, we had decided to provide detection by using an energy detection method with one LimeSDR since it’s faster and we wanted to learn about the Automatic Modulation Classification block in gr-inspector. (We managed to train a model with 97% success, but weren’t able to run the flowgraph.) After combining two modules, we made our custom block called decider and a custom OOT module called gr-dronesense. The decider runs a special algorithm upon receiving a detection signal that sends messages to the Pixhawk controller via serial to TTL converter and to the jammer via the iManager SBC interface. We also wrote a script to run two flowgraphs on the drone simultaneously.

Decider block diagram

For software on the ground side, we modified the existing gr-uaslink TX flowgraph connected to the B210 SDR. We also did Software in the Loop (SIL) testing with a Raspberry Pi before switching to the higher performance Advantech SBC. The deciderblock simply controls the jammer and the drone according to the signals on the flight area.

You can see some test videos of Dronesensein action on Youtube.

Drone signal detected!

Please note: some details cannot be shared due to a non-disclosure agreement.

About the Author

Ogün Levent

Izmir, Turkey




been a few days since I was labeled a threat who would shoot a fellow blogger in the back. I thought most of “kill them all” rhetoric had died down.

But a question had been raised, I believe honestly, that prompted another “kill the communists” post. The question “what direction?” did not get a satisfactory answer.

Since the focus has been on collectivism / communism, let’s review some numbers.

General statistics on welfare in the US indicates 25% of the population receives some form of transfer payment. Your government has promised some $19 Trillion in Social Security benefits and $30 Trillion in Medicare benefits. This roughly amounts to a $1 Million liability per Taxpayer in a pool of potential Taxpayers whose total assets are less than $500 Thousand per Citizen. (reference: USDEBTCLOCK.ORG)

From this finance lesson, let’s return to the “kill the communists” rhetoric. One out of every 4 people in your community are voluntarily recipients of stolen goods, or eagerly awaiting delivery of future stolen goods. Roughly 70 million people would have to be murdered to “kill the communists”.

Don’t have the stomach to move through your neighborhood and kill every 4th person? Not sure which of the four is deserving of a lethal sentence? Good, neither do I.

Our first conceit is a belief that we have properly identified our enemy: communists. It feels right. The first three planks in the communist manifesto attack private property, institute heavy taxation, and abolish inherited wealth.

But what is a communist? Merely a person who has not starved to death because you and I have fed him with the surplus from our commerce. A communist cannot harm you unless he directly threatens you with violence, and under common-law you are justified in responding with unorganized individual violence. A group of communists cannot harm you unless they employ a government to threaten violence to coerce you to submit to their will.

Let us clearly identify the enemy. The enemy is any attack on private wealth and private property. As I indicated previously, neither the Declaration of Independence, the Constitution, nor the Bill of Rights speak to any protection for private wealth and privateproperty. You cannot run there for help.

Governments, specifically the men that run them, work hard to make us submit to their will. Long before FDR and LBJ accelerated the adoption of naked communism within the United States, the 16th Amendment legalized theft of a portion of every-man’s paycheck. Lincoln killed 650,000 people to make the southern State submit to his will. And before that, state and local governments extorted property taxes to disburse “for public purposes”. Governments have coerced men to submit their persons and property to the will of others from the beginning of time.

A second conceit is that we, as partisans, can become cohesive enough to conduct meaningful, coordinated action against the leviathan of collectivist government.

So what useful direction can be given to Patriots faced with thieving governments and freeloading neighbors, who steal and consume our surplus? The obvious choice is between two options: cut the head off the snake, or remove the tip of the spear.

I don’t recommend an attempt to remove the head of the snake. The engine of evil will remain in place, operating on inertia, until the next bureaucrat is selected to run the machine.

I recommend an uncoordinated effort to remove the tip of the spear. Direct your individual ingenuity and energy into disrupting, at a local level, the theft of wealth by your various governments and their engines of re-distribution. The inevitable question is how?

This can take many forms dependent upon your courage and risk tolerance. Disrupt local town and city council discussions on topics of taxation and benefits. If you have the technical skills, disrupt local processes and systems of tax collection, disbursement, and the downward flow of funds from FedGov to local agencies. If you have the fortitude, infiltrate the agencies and conduct subtle sabotage from within. Finally, disrupt the personal lives of the employees who work in the agencies that run these functions.

Be creative in your escalation, but stay focused. The objective is to convince government managers and employees, at the operational level, to reconsider the morality of their chosen profession. Motivate them to seek honest employment in the private sector. If you are successful there will be consequences. Governments have agents with guns who will be directed to stop you, cage you, or worse.

The systemic theft we’re accustomed to cannot continue without the serfs who collect, count and re-distribute the coin. There are not enough enforcers on the payroll of municipal police to go door to door and threaten people directly for payment in the absence of a functional bureaucracy and its automated systems.

Others among you must simultaneously communicate the Fatal Conceit of socialism / communism / collectivism to your neighbors. That Fatal Conceit is the belief that rational man can use his intellect, along with tribal-level concepts of compassion, to replace the market-order that evolved through millennia of human experimentation. That Fatal Conceit which makes man hope he can engineer a centrally planned economy that doesn’t collapse and kill tens of millions he claims to help.

Expose the economic error of socialism: that the extended order necessary to feed, cloth, and otherwise maintain civilization cannot survive in in a centrally planned economy with managed markets. Explain how the extended order of modern civilization requires free markets and private property to deliver widespread prosperity.

To become prepared to do these tasks, read “Fatal Conceit”, by F.A.Hayek. It was the final work of a Nobel prize winning economist who earlier wrote “The Road to Serfdom”, sounding an alarm regarding state control of production and the relationship betweensocialism and totalitarianism.

Finally, recognize that reliance on tribe for organization, family values, and a desire for geo-political balkanization by the Patriot movement will likely inflict the same damage to the thin veneer of civilization as the central plan of the collectivists. To a lesser degree, perhaps, if trade across geographically dispersed free markets is actively encouraged and an absolute respect for private property is maintained.

Actions recommended above will remove the tip from the spear. As a consequence local, state, and even national government will probably collapse. If you elect to pursue this course, consider how you will provide short term compassionate care for neighbors whose welfare safety net has been removed.

In the interim, while you contemplate your resolve, reflect upon the fact that at no time in history has Freedom or Rightful Liberty prevailed on a significant scale; other than on the frontier at the boundary of civilization … and no such frontiers exist today.

You might want to consider how to live as free as possible in this un-free world. For that exercise I would recommend a book by Harry Browne “How I Found Freedom in an Unfree World”. An excellent summary can be foundhere .

Summary Against Modern Thought: Physics Cannot Show Our Wills Are Not Free

Summary Against Modern Thought: Physics Cannot Show Our Wills Are Not Free

Here’s proof of the ultimate limitation of science. The will can be moved by physics (if you like) but only by violence.


1 Now, we must not think that the souls of the heavens, if there be such, or any other created, separate, intellectual substances can directly insert a will-act into us or cause our act of choice to occur.

2 For the actions of all creatures are embraced under the order of divine providence, so they cannot operate outside its laws. But it is the law of providence that everything be moved immediately by its proximate cause. So, unless such an order were obeyed, a superior created cause could neither move nor do anything. Now, the proximate mover of the will is the good as apprehended, which is its object, and it is moved by it, just as sight is by color. So, no created substance can move the will except by means of a good which is understood. Now, this is done by showing it that something is a good thing to do: this is the act of persuading. Therefore, no created substance can act on the will, or be the cause of our act of choice, except in the way of a persuading agent.

Notes Hence both propaganda and education.

3 Again, a thing is by nature capable of being moved by, and of undergoing a passion from, an agent with a form by which the thing can be reduced to act, for every agent acts through its form. But the will is reduced to act by the desirable object which gives rest to its desire. Now, the will’s desire finds rest in the divine good only, as in its ultimate end, as is evident from what we said above. Therefore, God alone can move the will in the fashion of an agent.

4 Besides, as natural inclination in an inanimate thing, which is also called natural appetite, is related to its proper end, so also is the will, which is also called intellectual appetite, in an intellectual substance. Now, to give natural inclinations is the sole prerogative of Him Who has established the nature. So also, to incline the will to anything, is the sole prerogative of Him Who is the cause of the intellectual nature. Now, this is proper to God alone, as is evident from our earlier explanations. Therefore, He alone can incline our will to something.

Notes There is so much practical evidence of this that we didn’t need this technical proof. But it also means that the demons are under God’s control. So that if, perchance, they are pestering you, it is only by God’s permission or command. This is a most sobering thought.

5 Moreover, the violent, as is said in Ethics III [1], is “that whose principle is outside; the patient making no contribution of force.” So, if the will is moved by some external principle, the motion will be violent. Now, I am talking about being moved by some external principle which moves in the way of an agent, and not in the way of an end. But the violent is incompatible with the voluntary. So, it is impossible for the will to be moved by an extrinsic principle as by an agent; rather, every movement of the will must proceed from within. Now, no created substance is joined to the intellectual soul in regard to its inner parts, but only God, Who is alone the cause of its being and Who sustains it in being. Therefore, by God alone can voluntary movement be caused.

6 Furthermore, violent movement is opposed to natural and voluntary movement, because both of the latter must arise from an intrinsic source. The only way in which an external agent moves a thing naturally is by causing an intrinsic principle of motion within the movable thing. Thus, a generating agent, which gives the form of weight to a heavy generated body, moves it downward in a natural way.

No other extrinsic being can move a natural body without violence, except perhaps accidentally, by removing an impediment, and this uses a natural motion, or action, rather than causes it. So, the only agent that can cause a movement of the will, without violence, is that which causes an intrinsic principle of this movement, and such a principle is the very power of the will. Now, this agent is God, Who alone creates a soul, as we showed in Book Two. Therefore, God alone can move the will in the fashion of an agent, without violence.

7 Hence it is said in Proverbs (21:1): “The heart of the king is in the hand of the Lord; wherever He wishes, He turns it.” And again in Philippians (2:13): “It is God Who works in us, both to will and to accomplish, according to His good will.”

The Art of Deer Camp

Mason Dixon Survivalist Association

A cold, wet day in Deer Camp is still better than a day at work.

Training. Preparedness. What do these words mean to you? Are they a lifestyle, or just terms you use to pigeonhole your attempt at sounding “ready” for the calamity that many believe is coming? Have you lived in the woods for more than just an overnight camping trip? Have you used ALL THE GEAR you’ve collected for your survival if that calamity occurs. What about that dutch oven you bought on sale, but have never actually used?

Some of the best “Survivalist” oriented training I’ve ever done was during my weeks in “Deer Camp”. I hear from many people who tell me they don’t have an area to train in, and that they can’t carry a firearm in their State parks unless it’s hunting season. Then they ask how they should go about getting the experience needed…

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Why are so many women with good careers being forced to freeze their eggs?


Is this woman choosing a path that leads to marriage? Is this woman choosing a path that leads to marriage?

The New York Times says that more and more women are having to freeze their eggs because they can’t find good men to marry. The NYT doesn’t think that women are doing anything wrong. They blame the men for refusing to commit. According to feminism, women who value careers, abortion rights, no-fault divorce, big government, high taxes, etc. are doing everything right. But does it work?

I thought it might be a good idea to help Western women to make better decisions with men and marriage. Although setting out boundaries seems harsh and restrictive, it’s actually protective and loving. If we want women to get to a stable marriage and children, (what they really need long term, after they lose their looks and youth), then we should be bold about leading them.

The first thing to point out is that…

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Lessons Learned: My Walk Along the River this Morning

A.H. Trimble - Emergency preparedness information for disasters and grid-down

note: originally written/posted in 2015

Physical TrainingAs you know by now I try to do physical training 5+ times per week. I am also blessed with a job that pays me to do that each day. But I am cursed being in an area that at this time of year it is 100+ degrees and humid most days. But today was nice, hot but a stiff breeze blowing. Along the river it is usually a couple degrees cooler when the water is flowing. So I headed to the river for my PT today.

It was absolutely gorgeous along the river there this morning. I was even wearing my new tennis shoes. Hey, if you haven’t read my “Lessons Learned” about my tennis shoes you might want to read about that under Lessons Learned. I did my stretches and headed north along the river enjoying the stiff breeze blowing the bugs and…

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