Glowlink Engineering Team Uses Math to Solve Interference Geolocation Obstacles
[Satellite News 10-14-10] Since military operations began in heated battle arenas such as Iraq and Afghanistan, military command centers using X-band to communicate with critical unmanned aerial vehicles (UAVs) have dealt with interference issues at a disadvantage. Because there are only two X-band exclusive commercial satellites in orbit (Xtar’s EUR and LANT), geolocating the source of interference has provided military commanders with a difficult physics challenge – how do you triangulate geolocation signals to locate the source when another satellite is unavailable or located on the other side of the planet?
Satellite News spoke with Glowlink CEO Jeffrey Chu, who led his engineering team’s efforts in using mathematics to solve this issue and make single-satellite interference geolocation capabilities available.
Satellite News: What led you and your company to take on the technical and physical challenges of solving interference issues?
Chu: Glowlink was established 11 years ago with a mission and focus to solve all sorts of satellite interference problems using modern technology and our background is based on invention. Our single-satellite interference technology development efforts started in 2005 and 2006. The United States was engaged in two wars in Iraq and Afghanistan and satellite interference issues were increasingly becoming worse and more common for both defense and civilian uses. While modern technology was rapidly being introduced into these battle areas and satellite became a key element in this network structure, new sources of interference were created, even from terrorists using broadcasts to promote their messages. Combined with all of the small-dish satellite use in India, China and even Europe, the interference issue becomes even more prominent.
At the time, there were only two companies in the world – one in the United Kingdom and one in the United States – that manufactured geolocation solutions to deal with the interference issues. However, these systems cost well over a million dollars and were large, bulky and very difficult to operate. They were systems created by engineers for engineers.
Satellite News: As an engineering company, was it difficult to create a product with a wider customer base in mind?
Chu: No, because the key to Geolocation is simple in itself – it’s being able to acquire and capture the signals very accurately and precisely. One you’ve done that, the rest of it is really just math. When government customers came to us for better solutions, we thought that the way to realize this technology was to apply a different set of math to make it cheaper, more accurate and easier to use.
Our target for the cost of our product was set at $100,000 to $200,000 per system, versus the $1 to $2 million cost of the existing system. Our goal for accuracy was even more ambitious. At the time, interference geolocation accuracy within 40 to 50 miles was considered to be good. We wanted to achieve accuracy within a mile. We eventually got the accuracy to be within 10 miles, but there were times when we were able to achieve accuracy within 500 yards. For ease of use, we developed our solution to be the first integrated with Google Earth mapping. We also coupled the geolocation capability with monitoring, which makes it easier to use because it not only tells you where the interference is – it identifies what it is. We were also able to shrink the size of the unit considerably. All of these factors created an extremely popular solution in 2006, which was ground-breaking in cost-effectiveness.
Satellite News: How did you go from simplifying the products that already existed to developing a single-satellite capability that is new to the market?
Chu: We knew it was time to solve the underlying physics issues surrounding interference geolocation. The core of geolocation’s triangulation aspect comes from the Doppler effects and time differentials created by the very slight time delay, mere microseconds and even nanoseconds, between two received signals from two separate satellites. You receive two copies of the same signal traveling 22,000 miles up and down through two separate paths and you can exploit this slight difference.
While some satellites are stationary and fixed to the Earth’s orbit, most of these satellites move around a bit. But, what happens when these satellites aren’t available, namely the satellite being interfered with? Or, what happens when uncontrollable factors, such as weather, prevent you from being able to triangulate to locate the source of interference? Sometimes, the situation puts you in a position where you can’t do anything about it. For example, if you’re using X-band on a critical military UAV mission, you only have one X-band satellite available with no adjacent satellite. When both of them aren’t available, triangulation is impossible. Our single-satellite solution solves that issue and that is why this technology is a breakthrough.
Satellite News: How can you explain these physics issues with military and commercial customers who may not understand them?
Chu: I have an analogy to help explain this technology: Think about how a human looks at an object, and then figures out its proximity. The human does this with two eyes, and then the brain processes the information fed to it by the two images to figure it all out. When you cover one eye, it is exceedingly difficult to figure out the depth of an object with the single, uncovered eye. This is, in a sense, what the single-satellite geolocation capability does: it lets satellite users and owners figure out where on Earth an interference emitter is by using just one eye and by fundamentally rewiring how the brain processes that information.
Satellite News: How did you develop a way to reprocess geolocation data through one satellite?
Chu: The development of single-satellite involved using math and a lot of trial and error. Our engineers simulated satellite interference using the dishes on the roof of our own facility. At first, we were able to achieve single-satellite accuracy within 100 miles, which was not within our own standard of performance. Eventually, we were able to get it down to the 40- to 60-mile range, which is down to an accuracy range that is acceptable to us for a product and quite remarkable for using only a single satellite.
Satellite News: Is the math behind your formula the secret ingredient? Are you able to share any details of the math used?
Chu: We have to be very cautious about making sure this technology doesn’t fall into the wrong hands and we’re being very protective. Some of our competitors were hired to create these solutions, but ended up selling the same technology to commercial companies and adversaries that, in some cases, were the causes of interference in the first place. Our view isn’t from a competitive standpoint; it’s from a national interest point of view. All of us at Glowlink came from a defense background, so we understand the sensitivity of this technology. We want to manage this capability before it’s managed for us. We feel we have an obligation, both commercially and otherwise, to ensure these technologies are being applied in a responsible and effective way.
Satellite News: Have you been approached by potential partners?
Chu: Within a week of releasing this capability, we were approached by a variety of potential partners and customers, quite notably in X-band, but also others. I can’t say the names of these companies at this time, but we’re very excited by the response we received. We’re now making efforts to solidify these partnerships in both the commercial and government/military sectors.
Satellite News: How has the military responded to your technology efforts?
Chu: We have had a lot of encouragement from the U.S. government for our capabilities. They do not give us millions of dollars to develop our technology, but they always take a closer look at what we do and help test and evaluate the solutions. Some of those in the military are aware of us and some aren’t. Sometimes, we like to think of ourselves as the Military’s best-kept secret – like a good mechanic. But, we’re so excited for single-satellite technology that we want to get the word out there. Sometimes, as engineers, we get so caught up in the creative process that the communicative process of getting the word out there can prove to be more difficult. I’m planning to get out there to present our findings to the military and other customers and, hopefully, this technology will be widely adopted.