# A Single RF Emitter-Based Indoor Navigation Method for Autonomous Service Robots
## 7 Navigation Testing  
### Testing Scenarios  
Based on the motivating scenario, a number of benchmark tests were developed in order to gauge the performance of the system. Each test was designed to determine if the robot could complete a fundamental task such as driving straight and navigating around obstacles, and how quickly these tasks could be completed. These fundamental tasks indicate the ability to perform more complex operations in our motivating scenario, which is made up of different combinations of these fundamental tasks. These tests were performed using both the preliminary (with only target localisation and motion planning) and full (with mapping and path planning also) navigation systems, in order to determine if the final system outperforms the preliminary system. These tests varied in complexity to test a range of scenarios. For each test, the robot was considered to have completed the task when the robot was within 50 cm of the emitter (since the robot is 40 cm in diameter). These tests are presented diagrammatically in Figure 13.  
Scenario A involves a straight-line test with no obstacles as a control--it was expected that both systems would perform identically since the robot should just drive in a straight line to the goal. Scenario B is a similar test but with an obstacle in the way, preventing a direct straight-line path. In this test, it was expected that the full navigation system would outperform the preliminary system as the full navigation system should be able to find a path around the obstacle much more easily with the A* path planning algorithm, whereas the preliminary system would need to rotate away from the obstacle and iteratively try to find its way around the obstacle. In both scenarios, the robot drives in a direction with increasing RSS values. In Scenario C and D, the emitter was offset from the robot by 4 m in the x and y directions so that the emitter was at a 45\({}^{\circ}\) angle to the robot. Without any obstacles, it would be expected that the preliminary system would be able to drive in a straight-line to the goal, whereas the full system had to conform to the grid structure and would therefore drive along the perimeter of the square so that it makes a minimal number of turns. In Scenario C, we placed obstacles in the opposite corners of the area, so that this ideal L-shaped path is not possible. It was hypothesised that the preliminary system would be able to drive between the obstacles and arrive at the goal, whereas the full system would have to create a more complicated path. Due to there being a cost associated with turning, it was expected that the robot would not attempt to approximate a straight line, as this would require many turns and would not decrease the path sufficiently to balance out the increased turning cost. Similar to scenario A and B, the robot could reach the final target by simply driving in a direction with increasing RSS values. In Scenario D, the obstacles were placed so that they completely block the straight-line path to the emitter. It was expected that the full navigation system would outperform significantly in this test as the direct path to the goal is blocked, and the robot may need to drive away from the goal in order to avoid the obstacle. As the preliminary system has no global map or path, it has no ability to plot a path in what appears to be the opposite direction to the target in order to make overall progress. Due to this, it was expected to perform poorly and could be unable to complete the task. Lastly, in Scenario E, we created a U-turn test that required the robot to drive in the opposite direction to the radio signal in order to avoid a large obstacle. It was expected that the preliminary system would face significant difficulties and may not even be able to reach the goal, as it had no memory of the positions of previously encountered obstacles.