This is a technical but pretty readable treatment of the same topic: <a href="https:&#x2F;&#x2F;www.blackhat.com&#x2F;docs&#x2F;eu-15&#x2F;materials&#x2F;eu-15-Kang-Is-Your-Timespace-Safe-Time-And-Position-Spoofing-Opensourcely-wp.pdf" rel="nofollow">https:&#x2F;&#x2F;www.blackhat.com&#x2F;docs&#x2F;eu-15&#x2F;materials&#x2F;eu-15-Kang-Is-...</a>