National Timing Resilience and Security Act of 2017 This bill requires the Department of Transportation to provide for the establishment, sustainment, and operation of a complement to and backup for the timing component of the Global Positioning System (GPS). (GPS satellites contain atomic clocks that provide precise time data and allow GPS receivers to synchronize to those clocks.) The system must: (1) reduce critical dependencies on the GPS network; (2) ensure the availability of uncorrupted and non-degraded timing signals for military and civilian users if GPS timing signals are corrupted or otherwise unavailable; and (3) be land-based, operational in 2 years, and capable of operation for 20 years.