Dronebuster device in use during a training exercise for dealing with COTS drones
Surveillance

Methods to Counter Drones

Cheap drones, like the DJI Phantom, are becoming a ubiquitous technology. They can be cheaply used for surveillance (unmanned aerial surveillance), and in some cases they are being weaponized. How can you perform counter-drone operations? First of all – we’re assuming you are legally able to do this. There are “no drone airspace” restrictions in place around many government facilities, including Air Force Bases. Let’s look at the options. Kinetic Methods Physical damage to the drone through gunfire is also an option. But, firing off guns (especially up in the air) can lead to more trouble than it is worth. Bullets fired on a high arc have to land somewhere – and that’s both a safety risk to people and it is highly likely to cause collateral damage. Nets can be used to ensnare drones – but this is a relatively short range method. As we’ll see, there are easier ways to counter drones. Command and Control Disruption Systems like the Dronebuster are capable of interfering with the drones radio command frequencies. This effectively neutralizes the drone, and prevents it [Read More…]

Poster showing how GPS works
Surveillance

How GPS Works

GPS is a constellation of 24 or more satellites flying 20,350 km above the surface of the Earth. Each one circles the planet twice a day in one of six orbits to provide continuous, worldwide coverage. 1. GPS satellites broadcast radio signals providing their locations, status, and precise time (t1) from on-board atomic clocks. 2. The GPS radio signals travel through space at the speed of light (c), more than 299,792 km/second. 3. A GPS device receives the radio signals, noting their exact time of arrival (t2), and uses these to calculate its distance from each satellite in view. To calculate its distance from a satellite, a GPS device applies this formula to the satellite’s signal: distance = rate x time, where rate is (c) and time is how long the signal traveled through space. The signal’s travel time is the difference between the time broadcast by the satellite (t1) and the time the signal is received (t2). 4. Once a GPS device knows its distance from at least four satellites, it can use geometry to determine its location on [Read More…]

A handheld GPS receiver
Surveillance

GPS Spoofing

The Global Positioning System (or GPS) is a satellite navigation system that uses satellites to provide autonomous geo-spatial positioning. This technology is everywhere – it’s in your car, your smartphone, your watch, your fitness tracker, handheld GPS receivers, and more. But did you know that these satellite signals can be jammed – or even worse – deceived using something called GPS spoofing? Let’s take a look at this interesting topic of discussion. What we’re going to review here applies to any of the popular satnav systems – that includes GPS (the US satnav), Galileo GNSS (or Galileo Global Navigation Satellite System – the European version), and Russia’s GLONASS system. How does GPS work? There are multiple GPS satellites in orbit around the earth. Special chips can be included in nearly any electronic device that can read signals transmitted from the satellites. And combined with a bit of math – the device can determine your position with great accuracy as long as it can receive signals from at least 4 of the satellites overhead. Sound expensive? Yep – it is. (At [Read More…]

Thermal imagers have many uses in hunting, surveillance, and equipment maintenance
Surveillance

Thermal Imaging for Surveillance

In this article, we’re going to take a look at using thermal imaging (or “thermal vision”) for surveillance purposes. First of all, what do we mean by thermal imaging? All natural and manmade objects emit infrared energy as heat. With the right equipment we can detect the very subtle temperature differences of everything in view – and present it as a video image. Thermal imaging technology reveals what otherwise would be invisible to the naked eye. This sounds like exotic technology (and it sort of is) but you’ll also be surprised at just how capable and affordable these thermal vision devices have become. Having said that – “affordable” is relative in this case. This IR gear is more expensive than night vision devices that use Image Intensification methods that amplify ambient light. There are also a lot of interesting uses of IR that aren’t just for surveillance – we’ll talk about those too. Advantages of Thermal Imaging for Surveillance Thermal Imaging has some substantial benefits over class night vision using Image Intensification. Thermal imaging works in daylight or darkness – [Read More…]

View through a high quality night vision device.
Surveillance

Night Vision Devices for Surveillance

Let’s look at Night Vision Devices (NVD) for long range surveillance. We’re going to review how night vision works, and how you can practically apply it for medium to long range surveillance. We’ll be talking about Image Intensification (I2 or I2) technology. How Night Vision Through Image Intensification Works Let’s talk about Image Intensification. This is a light intensification method. In a nutshell, the electronics take the available ambient light (such as moonlight, starlight, etc.) and amplify it to a level that can be seen. It’s important to note that there is not much ability to determine colors with night vision. Depth perception can be a problem as well. What does this night vision view look like? Here’s an example. The image is shades of green – a familiar look you’ve probably seen in the movies (or maybe in real life!) Why is it green? Because green phosphorous is used as part of the light intensification electronics. Let’s take a look at that. Light (consisting of “photons”) comes into the device’s lenses. The device contains one or more “Image Intensification [Read More…]