April 01, 2013
Credit: O3B Networks
In 2007, when O3b Networks began planning a Ka-band satellite constellation orbiting at the unlikely altitude of 8,069 km (5,000 mi.) over the equator, the startup fleet operator was hoping to bring high-speed Internet to emerging markets in underdeveloped parts of the planet—the so-called “other three billion” for which the company is named.
While most telecommunications satellites operate from a fixed point in geostationary orbit 36,000 km above the equator, O3b is banking on the nearness of medium Earth orbit to reduce network latency—the lag users experience when loading a web page.
“The driver behind the orbital altitude is to achieve a roundtrip latency of less than 150 milliseconds, which is the typical user experience on the Internet,” says Brian Holz, O3b's chief technical officer.
Designed with a coverage area that falls between 45 deg. north and south of the equator, the constellation's architecture will use 10 steerable Ka-band spot beams on each spacecraft to communicate with a ground segment that will require users to install tracking antennas capable of following the orbiting satellites, handing off from one to another as they pass slowly overhead.
Holz says the company is installing eight teleports around the globe, with a network operations center in Virginia and a satellite operations center in Luxembourg.
“We're investing in our ground terminals, including 1.8-meter and 2.4-meter antennas built by General Dynamics and a 4.5-meter system and 7.3-meter system available from ViaSat,” he says, adding that Comtech is providing modems tailored to support mobile backhaul while Gilat will supply networking hubs and O3b customer modems.
Despite the inherent risk in O3b's unorthodox approach to the system architecture—most communications satellites in geostationary orbit use fixed antennas that need little in the way of maintenance and repair—the concept has drawn the attention of SES, the world's second largest satellite fleet operator in terms of revenue. SES is now a major investor in the initial constellation, which has grown from eight to 12 satellites as a result of the additional financial backing.