Skip to main content

RF Shorts for Dec. 5, 2014

How GPS Satellites Make it Into Orbit

If you've ever wondered how GPS satellites make it into orbit, you'll find the article GPS analysts bridge gap between launch, orbit/by Scott Prater in the Schriever Sentinel interesting. He writes, “Between the time a satellite is launched and the 50th Space Wing receives satellite control authority for it, a small team is busy testing and evaluating, ensuring that each spacecraft is ready to begin its job of providing position, navigation, and timing to more than 3 billion worldwide users.”

Their work begins more than 60 days before the launch, testing the GPS satellite on the ground to make sure all components are functioning properly. After the satellite is launched testing and evaluation of the second payload, the Nuclear Detonation Detection System (NDS). Most people don't recognize that system is present on every GPS satellite. 2nd Lt. Christopher Phillips explained, “NDS performs an important mission. It helps verify the Limited Test Ban Treaty of 1963. It makes sense. The whole reason the GPS constellation has these nuclear detonation sensors is because it provides global coverage. We can see every part of the planet.”

Other tests verify the systems tested on the ground are working once the satellite is in orbit as the various satellite components are turned on. The precise orbit trajectory of the GPS satellite has to be determined.

See Scott Prater's article for more details on what it takes to get the GPS satellites we depend on operational.

How Will 5G Change the World?

While you'll find few details on 5G technology in Ed Ram's BBC News article How will the 5G network change the world?, it does provide a glimpse at how a technology that can deliver speeds well above 1 Gbps could impact communications. Ram quotes Professor Rahim Tafazolli, leader of the U.K.'s multimillion-pound government-funded 5G Innovation Centre at the University of Surrey saying he believes it is possible to run a wireless data connection at 800 Gbps, 100 times faster than current 5G testing.

Tafazolli said devices will be able to choose dynamically between which of three still-to-be determined bandwidths they will use to avoid any of the frequencies from becoming overloaded. “Only once these frequencies are set and established can product development begin.”

The article doesn't mention the impact on broadcasting, but once this magnitude of data capacity becomes available over wireless networks at a reasonable price, it is hard to see how broadcasting and even cable TV, as we know it now, will be able to compete.