It could be. However even though it’s a .gov server, it’s not clear what the usage rights of that code, and indeed all of the gps toolbox codes, are. If it was all US federal government produced it would be public domain. But if it any was contractor produced, or produced by private individuals, then it’s not so clear. The journal they’re collecting the code for is published by Springer.  I didn’t see any license or clear usage terms on the site.

In any case, as Rik said in comment #1, there’s some underlying work that needs to be done before we can emulate Matlab a polaraxes objects to being making a compatible polarplot.  I assume it may be the same case with skyplot?

polarplot is still a missing function in 5.2.0

a new polar plot function has been introduced in matlab 2016a with intent to supersede the 'polar' function, which is now listed as 'not recommended'. polarplot allows for more flexible plot options.

http://www.mathworks.com/help/matlab/ref/polarplot.html

relates to an older bug #35565