As you may know, Marcos Costales has created a GPS navigation application for Ubuntu Touch based on OpenStreetMap and OSRM. Among others, it supports setting a destination, displays the arrival time, gives turn-by-turn indications, shows how many kilometers or miles are left until the destination is reached, has a speed indicator, can be used on both landscape and portrait views and permits the users to set a home place with a single tap on the map. The app is for driving only, so it cannot give you walking indications.
Recently, the developer has announced that a major update has been implemented, GPS Navigation 0.18 bringing important fixes and new features. It now keeps the display on, a brightness fix has been included, a feature for saving the current position and destination has been added, an Autozoom feature has been added, the route indication has been enhanced and a volume controller has been added for the voices.