[10-24-07 – Satellite News] Com Dev International Ltd. has developed a way to “de-collide” the hundreds or thousands of signals emitted by the maritime Advanced Identification System (AIS), solving the problems traditionally associated with space-based data collection and potentially expanding the use of the system.

The AIS, a VHF broadcast system required aboard every ship weighing more than 300 tons, was originally put in place to avoid collisions between ships within 50 nautical miles of each other. The system broadcasts basic information such as a ship’s identity, position, course, speed and navigational status every two to 10 seconds to other ships and land-based receivers.

Com Dev, based in Cambridge, Ontario, Canada, has been looking at the issue of maritime communication and specific AIS issues for about two years now, Peter Mabson, vice president of corporate development, said.

“We started getting familiar with the AIS and started hearing from people about the need for long-range tracking. We put two and two together and thought, why not use the existing system for long-range tracking?” he said.

The AIS data is now collected primarily from other ships and land-based receivers with a limited range of approximately 50 nautical miles. A satellite collection system would eliminate the distance limitation, as well as the cost of building the ground stations, which Mabson says has limited the desire of countries with a long coastline to invest in the system.

Com Dev has now developed a process that solves the primary technical barrier to a space-based system, which is de-colliding the huge number of signals that are received simultaneously from ships in a satellite field of view. The company has been working not only on spacecraft design, but also on the design of the processors able to de-collide signals and the characteristics of the signals. Com Dev’s solution is ready to go through a series of trials to demonstrate data detection capability from space, Mabson said.

The process, which will separate the signals into meaningful information, encrypt it and send it back to data receivers, will undergo progressive demonstrations, starting with an aircraft trial next month. The aircraft will follow the North American coastline, from Halifax, Nova Scotia to the Bermuda Islands, Mabson said. The aircraft will be able to see about 500 kilometers at a time.

Com Dev has partnered with the University of Toronto’s Institute for Aerospace Studies Space Flight Laboratory for the second stage of the project, which will involve a prototype test in orbit aboard a nanosatellite to be launched in the second quarter of 2008. The nanosatellite will have a mission life of about a year. The final test will either use a dedicated microsatellite or be hosted as secondary payloads on other spacecraft, such as low earth orbit constellations, toward the end of 2009, Mabson estimates.

Mabson said the company is talking to several interested parties about financing the satellite. “We could end up financing to build the spacecraft if we have sufficient secured interest from people who will pay for the data that is provided from that spacecraft,” he said. There could also be various governments that might want to pay to put the assets up in orbit. The Canadian Department of National Defense has already signed a small contract with Com Dev to obtain data it will use to evaluate the results of the trials.

“This has many very exciting possibilities,” Mabson said. “There are all sorts of applications that could be enabled if we prove that this is successful. Search and rescue is an obvious one. If you’re going 400 or 500 miles offshore to rescue somebody, it would be really helpful to you know exactly where they were. In the case of this system, we would know right up to the point where the ship stopped transmitting its signal. And we’d have predictions, because you’d know the history of where the ship was, how fast it was moving, so you can probably predict where it would have gone.”