Interesting application of frequency generation using GPS: http://www.navspark.com.tw/blog/1pps-phase-locked-programmable-frequency-output
It gives a link to the DDS board but not to the "NS-T precision timing mode receiver". What is that?
NS-T precision timing GPS module is this one: http://navspark.mybigcommerce.com/ns-t-precision-timing-mode-gps-receiver/
Additional result showing time jitter removal with PLL: http://www.navspark.com.tw/blog/more-ns-t-programmable-frequency-testing