# Topological Navigation and Localization in
## 5 Results and Discussion  
The validation in the test-field was executed from March to June of 2017, requiring approximately 300 h of work. On-site tests were carried out in a medium-scale sublevel stopping mining operation called the _Mina 21 de Mayo_ (21 st of May Mine), the property of _Compania Minera San Geronimo_, located in the north of Chile. The tests were comprised of two phases:  
* During the first batch of tests in 2017, approximately 2300 work-hours were needed to test the system, of which about 800 were on-site; 600 were for remote support and system troubleshooting; 800 were with OEM remote support on-site; 100 h were spent traveling from the nearest city, La Serena, Chile, to the mine. The first batch included 66 days of testing, including installation of hardware on the LHD, network infrastructure on the tunnel, tele-operation station, and CCTV cameras. First underground tele-operation tests were done on day 32, which were followed by assisted tele-operation and self-localization tests. * During the second batch of tests, performed in 2018, about 2900 work-hours were required, including 1000 on-site, 1000 with OEM support onsite, 750 with remote support, and 150 spent traveling from the nearest city to the mine. This second batch of tests lasted for 77 days. First, autonomous navigation tests took place on day 32. Further tests included approximately 150 h of autonomous navigation. It is important to note that the LHD was also used to test an autonomous loading system, so not all on site test were for the autonomous navigation system. Between the first and second phases, several upgrades were made to the system in order to improve its robustness, consistency, and performance. The most important improvement was on the self-localization system, because the first batch of tests proved that the initial method (not described here) could not maintain the self-localization estimation along the test tunnel. Assisted tele-operation tests during the first phase were mainly used to tune the parameters of the _Guidance_ module for the tunnel and intersection navigation modes (Equations (13), (14), (16), and (18)). Once the autonomous navigation was operating properly, further adjustments were made to all system's parameters, including the parameters for the _Command Executor_ module (Equations (20) and (21)). Parameters of the map were tuned, such as the maximum speed for certain segments of the tunnel, 2D poses of APs/WPs, and navigation modes for different parts of the tunnel. On-site, at the mine, two validations were carried out: surface level tests, and underground tests. Surface level tests were done to test all the modules before entering the mine, and to visualize any problem that the LHD or the implemented automation system could have. After the arrival of the machine at the mine site, all sensors, antennas, and communication modules were re-installed and tested. The first teleoperation tests were carried out on the surface, on one of the dump sites of the mine, to verify that the operation of the LHD was correct. The second validation was done inside the mine in a production tunnel. The system was tested incrementally from teleoperation to full autonomous operation. A network infrastructure was installed inside the test tunnel, and an operating station, consisting of a computer, screens, and controls, was installed inside the mine. Communication tests were carried out between the LHD inside the mine and the computer in the operation center. Teleoperation and assisted teleoperation modes were the first functionalities tested. In the first mode, the operator drives the equipment just as would be done aboard, and in the second mode the operator mainly indicates the direction of movement and the system keeps the LHD away from the walls keeping it from colliding with them. The system was successful in avoiding collisions between the equipment and the inner walls of the tunnel, and the general performance of the operation was similar to manual navigation.