Download MATLAB Software - Introduction to Global Navigation Satellite Systems | ASEN 5090 and more Study notes Aerospace Engineering in PDF only on Docsity! ASEN 5090 Introduction to GNSS Fall 2008 ASEN5090_Visibility Project.doc 1 GNSS VISIBILITY Assigned : 29 August 2008 Due : 12 September 2008 Individual Assignment OBJECTIVES • Predict satellite visibility using the broadcast almanac • Explore the visibility limits at different locations on the earth OVERVIEW This software project provides you with some basic codes for determining satellite position from the broadcast almanac data (note: the broadcast almanac is not the same as the broadcast ephemeris). You will use and expand on these codes to generate visibility plots and explore satellite coverage at different locations on the earth. We’ll also add a PDOP calculation to characterize the geometry. ASSIGNMENT 1) You’ve been provided with code that computes satellite and user positions in ECEF coordinates. (See run_vis.m). Familiarize yourself with the code, working out the file formats, input, and output. This code requires YUMA almanac formats. Note: these codes were written by PC people, and thus do not necessarily work properly in unix (or on a Mac). 2) (10 pts) Write a function that takes as input a satellite and a user position in ECEF coordinates and returns the elevation and azimuth (getAzEl_ASEN5190.m). Write a separate function that determines if the satellite is visible based on the elevation and the mask angle. Check to make sure that both work correctly. 3) (10 pts) Find the satellites visible at 2007 /9/7 12:00 in Boulder (Latitude 40.0, Longitude -105.0, and Altitude 1631 meters). Turn in satellite names, azimuth and elevation angle in degrees to 3 decimal points. 4) (20 pts) Create an AZEL plot of the satellites visible throughout the day on Sept 7, 2007 at the following locations on the earth: a) 0 N, 0 E b) 90 N, 0 E c) Boulder d) Somewhere in Australia Describe the differences in visibility. 5) (10 pts) Using your previous results for Boulder, CO, calculate and plot the number of satellites that are visible as a function of time. On the same plot, show the number of satellites above 10 degrees. 6) (10 pts) For Boulder, CO, compute the time shift for any three satellites to reappear in the same place in the sky on Sept 6 and 7. Describe your approach and your results using figures or tables as needed. ASEN 5090 Introduction to GNSS Fall 2008 ASEN5090_Visibility Project.doc 2 REPORT OUTLINE AND GRADING Title Page 5 Executive Summary - Summarize briefly what was done, results, and conclusions. Provide an overview of the rest of your report. 60 Answers to questions. 5 Conclusions and Recommendations - describe what you learned about satellite visibility and recommend changes to the project, the codes, or potential for future investigations References Appendix - Well commented code for any new or modified routines 10 Style and Clarity - clarity, spelling, grammar, organization, neatness 80 TOTAL
