Detection of ground actions from satellites


By. Dr Kayyali Mohamed, KSF Space Foundation USA

Satellite sensors can detect light that we can’t see. The electromagnetic energy reflects off the Earth’s surface and up to the satellite sensor, which collects and records information about that energy. That information is transmitted to a receiving station in the form of data that are processed into an image.

The ATLAS detector system involves elaborate trigger and data acquisition systems [Cambridge, 2001; Mandjavidze, 1998; ATLAS; KTH, 2002; LIP, 2002]. A trigger system is an electronic device or an algorithm applied to the data that flags an event for further analysis, while rejecting other events as background. The purpose of the ATLAS detector system is to discover and, if found, to study the Higgs particle, which is of critical importance in particle theories and is directly related to the concept of (particle) mass. In the case of the ATLAS detector one may describe it as consisting of four major parts: a magnet, inner tracker, calorimeter, and muon spectrometer. Like layers in an onion, these systems surround the beam pipe where collisions of protons occur. The ATLAS detector will generate a torrent of data. To “digest” this data flood, an elaborate system of triggers, data acquisition electronics, and data processing is required. When the protons collide, only a minute fraction of the events are “interesting” and may tell us about new particles. Most other events are “ordinary” collisions (referred to as “background”).

The trigger system must filter out the enormous number of background events without throwing out the interesting ones. It will select 100 “interesting” events per second out of 1000 million total events. The data acquisition system will be channeling the data from the detectors to the storage device. Finally, the computing system will be analyzing 1000 million events recorded per year. One of the biggest and most comply. 

“The threat is certainly evolving at an unprecedented fast pace that we haven’t seen before,” Denaro said during a pre-launch briefing. “We’re looking at a range of targets and missiles in the hypersonic domain that are far more maneuverable, they’re dimmer, they’re harder to see.”

“And that’s requiring a new approach to how we both detect and then track all these missiles throughout their flight,” Denaro added. 

Space Force is already developing Next Generation Overhead Persistent Infrared — OPIR — satellites that eventually will replace current Space-Based Infrared System, or SBIRS, early warning satellites.

Lockheed Martin holds a $4.9 billion contract to build three OPIR geosynchronous satellites while Northrop Grumman is providing two lower-altitude polar satellites under a separate $2.4 billion contract.

Knowledge that is helpful for image interpretation include: 

1. Time of registration 

2. General location of registration site 

3. Precise location of registration site 

4. Detailed cartographic information about the image 

5. What is expected to be found in the image

There are basically four types of satellites or space-based functions when it comes to collect information about the Earth and activities there upon. These types are remote sensing satellites using optical sensors, satellites using (thermal) infrared sensors for detection of ballistic missile launches, remote sensing satellites using imaging radar techniques (SAR systems), and satellites for so-called signals intelligence. 


Cambridge, 2001; Mandjavidze, 1998; ATLAS; KTH, 2002; LIP, 2002

Earth Satellites and Detection of Air and Ground-based Activities, Ulf Ekblad 2005

Digital Image Processing, Kayyali Mohamed, USMP University, ISBN 9972720144, 9789972720147