Exercise #12: GPS Navigation

Introduction

Last week we were able to learn and utilize traditional navigation skills by navigating to pre-selected and placed points in the Priory. This week we were given the opportunity to build our own coarse for future classes. By creating a project onto a GPS unit (we chose the Trimble Juno Unit) we were then to navigate to points of our choice, mark the trees, and record the points.

Study Area

Once again this week we were at the UWEC Priory (Fig 1). Our study area was divided up into a different area for each given group. This was so the courses would not overlap or be located in one portion of the area. Our group had the far Northeast corner. The weather was Sunny, mid 70 degrees Fahrenheit, and little to no wind.

\

Figure 1. The UWEC Priory.

Methods

Once our group was given the selected area for our coarse, we took the paper maps we had created earlier in the semester and used last week and plotted points where we felt necessary. We wanted to make sure the points included distance, terrain, and were easily able to be navigated to within the class period. By having a project created on the Juno Unit (Fig 2), the Priory satellite imagery was available for us to use. This was our means to navigating to the points we selected. Once the points were navigated to, we were to mark the tree with the pink ribbon, label the ribbon with the group number and point number, and take a picture. The pictures of the five (5) points can be seen below (Fig 3-7).

Figure 2. The Trimble Juno 3D GPS unit used for the activity.

 

 

 

Figure 3. Point #2-1 for Coarse #2.

 

 

Figure 4. Point #2-2 for Coarse #2.

 

Figure 5. Point #2-3 for Coarse #2.

 

Figure 6. Point #2-4 for Coarse #2.

  

Figure 7. Point #2-5 for Coarse #2.

 

 

The points that we plotted were then loaded back into ArcMap and mapped (Fig 8). This also allowed us to create a Shapefile to submit so the data could be recorded for future classes. The attribute table gives the location of the points (in UTM) and also notes about the location of the tree.

 

 

Figure 8. Map of Coarse #2. The green dots represent the planned spot for the points, while the red dots are the actual locations of the points.

 

Figure 9. Attribute table of the points for Coarse #2.

 



 

Discussion

 

This exercise was extremely helpful with refreshing the skills we learned earlier in the semester, but also applying those skills to a navigation situation. Although you would think it would be easy to navigate to these points, there are still errors associated with the GPS unit. Looking at the map above, not one of the points match up exactly. This could be due to a low satellite frequency on the GPS or the group just saying we were "close enough" and marked the point. You still also need to account for terrain and obstacles while navigating.