Exercise 12: GPS Navigation

Introduction

The previous exercise involved navigating to 5 points at the Priory using a map and compass. This week's exercise challenged each team to complete the entire course of 15 points with two added elements: a GPS unit and paintball rifles. ArcPad enabled GPS units were used to deploy the navigation map and course points created in ArcMap. Aside from the designated starting point for each team, the points could be visited in any order as long as the no shooting zones next to buildings were avoided. 

Methods

For this exercise, each team was given a different starting point in order to avoid firefights close to the no shooting zones. With our starting point located in the woods to the northwest of the priory campus, we decided to work our way through the points in a clockwise direction. 

Figure 1. The navigation map that was created in ArcMap and deployed onto the ArcPad enabled Juno GPS unit.

Using ArcMap, the map document was deployed onto the Juno unit by using the ArcPad Manager toolset. The map document was exported in a file type that was compatible with the unit and was placed on the SD card within the unit. 

Figure 2. The navigation map after it was deployed onto the Juno 3B unit. The large cluttered labels made it difficult to see our location which made navigation a difficult task. 

Results

Although pictures would have been great for this blog post, carrying a camera or smartphone was not considered a priority while engaging in firefights and dodging incoming fire. Due to the cluttered labels on the map and the spotty signals from within the forest, the GPS was essentially useless for navigation. The location marker on the unit was always changing directions and locations which made it extremely difficult to narrow down our current location let alone travel to the next point. It was at this point that we decided to solely rely on the map we printed, as the terrain on the map was recognizable from the ground for the most part. Somehow, we made it to 12 of the 15 points and encountered a few enemy teams along the way. We quickly realized that we were fighting the same group multiple times due to their similar route, and we decided upon a truce for the remainder of the exercise. 

When we attempted to zoom in and zoom out with the map, the ArcPad application would occasionally freeze and we would have to reset the whole unit. Each time we reset the unit, we noticed that the calibration decreased and decreased until the touch screen recognized the touch more than an inch away from the pen. Due to this problem, we were unable to plot any points at each of the flags let alone navigate using the GPS. A tracklog was also turned on before each group set off and unfortunately the data didn't record for any of the 6 groups.  

Discussion

Due to the many problems we encountered with the map document, the GPS signal, and the GPS touch screen, it is hard to say what could have been improved. Some factors were within our control while others were unsolvable and unforeseeable. The paintball factor added in a lot of stress when deciding routes, and it obviously made an impact on the team's decision making and morale. 

Exercise 11: Map and Compass Navigation

Introduction

The step up for this blog can be found in this earlier post. This exercise took us to the Priory, a university owned property with dense woods and steep ravines. The class was split into teams of 3 and sent out to navigate through one of three different courses on the property using only a map and compass. In areas of dense forest GPS signals can become weak and inaccurate, and this exercise taught us a valuable lesson that traditional navigation techniques are simple to learn, extremely accurate and very cost effective. 

Methods

Once our group assembled at the Priory, the first step was to receive the coordinates for the course points and plot them on the printed maps we created. Emily's map was used since it was the simplest design and was easy on the eyes. She also used the 5m contours which were a lot less cluttered than the 2 foot contours I had used. These points were represented by blaze orange flags hung onto trees, containing a hole puncher to prove our visit. With the five course points plotted directly on the map, we could then draw lines between each point using a straightedge in the correct order for measuring azimuth. We placed the center of the compass dial on the starting point, aligned the compass meridians with map north, and recorded the azimuth we would need to head towards to travel to each point. 

Figure 1. A compass and straightedge are necessary to accurately plot the route on a map. 

To properly navigate this course with the resources given to us, it was essential that each team member executed their role flawlessly. I was given the "runner" position which meant I would head off in the direction of travel until I was barely visible. The other team members would shout at me and tell me to move right or left in order to stay exactly on the line of travel. The next team member was the "counter", and would count the number of paces it took to travel from the starting point to me. The last team member who held the compass would then travel to us once the counting was completed and we would repeat the process until we reached the flag. Sometimes we would travel the correct distance and wouldn't arrive at a flag, so a marker like a backpack was left on the end point and we would spread out to find the flag. If we found out that we had traveled the route wrong, we would return to the backpack and adjust the route accordingly. 

Results

The navigation exercise was a success and at the end of the day, we made it to each point and safely back to the starting location. The third point that we traveled to was accidentally plotted in the wrong location by me, and resulted in us being about 200 meters off course. Luckily we included the aerial imagery on the map, and we were able to find a landmark to use as a temporary starting point while we navigated to the third point using a new azimuth measurement. Since the grid was quite large on the map, it was difficult to plot the points exactly where they should have been, but once we got to the plotted area the flag was bright enough to be seen from about 100 meters away. 

Discussion

Some small changes I think could have been made to our methods involve the map construction. The font of the UTM coordinates were very light and hard to see against the light blue backdrop of the map. Also, additional ticks in the grid would have been nice considering how accurate our points had to be in order to complete the exercise.