# Magnetic North – Magnetic North Pole

What is the magnetic field, anyway? Earth’s core is made of molten iron, and that geothermal energy is what keeps us warm, gravitized, and protected from the sun’s unrelenting radiation. As molten iron swirls, rises, is cooled, and falls back into the center, the convection (or circulating heat, the same as a convection oven) powers continental drift and also generates the magnetosphere.

# The Plane Crash That Gave Americans GPS

The U.S. had already launched into orbit almost a dozen satellites that could help locate its military craft, on land, in the air, or on the sea. But the use of the system was restricted. (It was meant, for instance, to help powerful weapons hit their targets—it wasn’t the sort of tool governments usually want to make publicly available.) Now, Reagan said, as soon as the next iteration of the GPS system was working, it would be available for free.

It took more than \$10 billion and until over 10 years for the second version of the U.S.’s GPS system to come fully online. But in 1995, as promised, it was available to private companies for consumer applications. Sort of. The government had built in some protection for itself—”selective availability,” which reserved access to the best, most precise signals for the U.S. military (and anyone it chose to share that power with).

# British MoD works on ‘quantum compass’ technology to replace GPS

At their lowest energies, the atoms become the coldest known bodies in the universe. Super-cooled low energy atoms are extremely sensitive to changes in the Earth’s magnetic and gravitational field.

If trapped on a small device, their fluctuations can allow scientists to track their movements from great distances away and their locations pinpointed with extreme precision.

# Calculating distance between longitude and latitude pairs

Problem: I need a simple way to calculate distance between two pairs of longitude and latitude coordinates.

Apparently there are several ways of making this calculation.  Since none of my calculations would exceed 15 miles I was able to use the flat earth calculation which is the simplest but inaccurate as distances increase between the two points according to this wikipedia article.  Here’s a blurb about the flat-earth formula:

## Flat-surface formula

A planar approximation for the surface of the earth may be useful over small distances. The accuracy of distance calculations using this approximation become increasingly inaccurate as:

• The separation between the points becomes greater;
• A point becomes closer to a geographic pole.

There were a bunch of sites that came up with all the different formulae over this but I’m not launching a satellite or programming a guided missile. The following code came from perlmonks which is a very reputable reference for anything to do with programming in perl. Here is the subroutine I chose to use. Article was written in 2002.

``` use Math::Trig sub FlatEarth { my (\$lat1, \$long1, \$lat2, \$long2) = @_; my \$r=3956; my \$a = (pi/2)- deg2rad(\$lat1); my \$b = (pi/2)- deg2rad(\$lat2) my \$c = sqrt(\$a**2 + \$b**2 - 2 * \$a *\$b *cos(deg2rad(\$long2)-deg2rad(\$long1))); my \$dist = \$c * \$r; return \$dist; }```

The above code seems to work.  Most of the calculations I needed to do were under a mile.

# College students hijack \$80 million yacht with GPS signal spoofing

A group of students at the University of Texas at Austin built and successfully tested a GPS spoofing device to remotely redirect an \$80 million yacht onto a different route, the Houston Chronicle reports. The project, which was completed with the permission of the yacht’s owners in the Mediterranean Sea this past June, is explained in the video below.

# A Microsoft Research Project Offloads GPS Data and Calculations to the Cloud to Save Battery Life.

The biggest power hog inside a smartphone is the GPS chip. This component can take 30 seconds just to acquire the satellite data necessary to get the information it needs for an initial location fix; it then has to churn through the downloaded codes to calculate its location precisely.

Microsoft researchers reduced that power consumption dramatically by offloading some of the work to the cloud.

# Researchers find crippling flaws in global GPS

A 45-second crafted GPS message could bring down up to 30 percent of the global GPS Continuously Operating Reference Stations (CORS), while other attacks could take down 20 percent of NTRIP networks, security boffins from Carnegie Mellon University and firm Coherent Navigation wrote in a paper. (pdf)

The GPS data level attacks caused more damage than previous spoofing attacks and were able to trigger a remote crash of high-end professional receivers.

# Deployment of Europe’s Galileo constellation continues

Galileo is Europe’s own global satellite navigation system. It will consist of 30 satellites and their associated ground infrastructure.

The four satellites launched during the IOV phase are the nucleus of the constellation that will then be extended to reach its FOC.