Tutorial Electronics and Programming: Geotagging Nikon DSLR with Vectornav VN-200 GPS (Lattitude & Longitude) + IMU (Compass Heading)
Nikon D800/D800E - still no built-in GPS » foolography
Solmeta Geotagger Pro 2 GPS Unit with Pro2 USB Cable, Cable-D (for Nikon D5, D850, D810/810A, D800/D800E, D500, D4, D3-series, D700, D300-series, D2X, D2XS, D2HS, D200) at KEH Camera
Amazon.com : GPS Receiver Compatible with Nikon, Micnova GPS-N Plus DSLR Camera GPS Unit Navigation Geotagging for Nikon D800 D3200 D3300 D90 D7100 D5200 D4 D600 D5100 : Electronics
Micnova GPS-N Plus GPS Receiver for Nikon Cameras - NEW | eBay
GP-1A GPS Unit | Nikon
Amazon.com : GPS Receiver Compatible with Nikon, Micnova GPS-N Plus DSLR Camera GPS Unit Navigation Geotagging for Nikon D800 D3200 D3300 D90 D7100 D5200 D4 D600 D5100 : Electronics
Sevenoak Electronic Gps-n1 Cable For Camera Gps For Nikon D200 D300 D300s D700 D800 D2xs D2hs D3 D4 D3x D3s - Photo Studio Kits - AliExpress