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Lab-Material GNSS Processing Environment

This directory provides all the resources and a complete MATLAB environment needed to complete the GNSS lab assignment for the Wireless and Device-to-Device Communication Security course. It supports processing Android GNSS Logger measurements, including pseudoranges, C/N₀, weighted‑least‑squares PVT, ADR, and spoofing experiments. You can run demo datasets, your own Android logs, and spoofing tests, with all outputs automatically saved under results/.

Dependencies

  • MATLAB R2020a or later (no additional toolboxes required).
  • Internet access (optional) for NASA CCDIS ephemeris downloads.
  • GNSSLogger App on Android (to generate new logs).

Directory Structure

Lab-Material/
├── configs/             # Experiment configuration files
│   └── spoof_configs/   # Spoofing configuration scripts
├── data/                # GNSS log data
├── results/             # Auto‑created output figures and data
├── scripts/
│   ├── matlab/
│   │   ├── core/        # Core reusable functions
│   │   ├── tasks/       # Top‑level experiment scripts
│   │   ├── utils/       # Helper functions
│   │   └── original/    # Legacy scripts
│   └── python/          # Python scripts
├── tools/
│   └── opensource/      # GNSS‑processing functions and datasets
│       ├── library/     # GNSS‑processing functions
│       └── demoFiles/   # Provided demo datasets
├── resources/           # Additional resources
└── README.md            # This file

File Roles

Core utilities (scripts/matlab/core)

File Purpose
PathManager.m Defines all project folder paths
InitProject.m Adds paths, creates results/
SetDataFilter.m Returns default GNSS data‑filter settings
SaveFigures.m Saves a list of figure handles to PNG/FIG files
ProcessGnssMeasScript.m Core GNSS processing and plotting
FilterPositionOutliers.m Removes unrealistic position jumps

Experiment tasks (scripts/matlab/tasks)

Script Function
RunDatasetAnalysis.m Process all tests for Samsung A51 and Xiaomi 11T Pro datasets
RunDemo.m Single demo run with spoofing & ADR
SpoofingTest.m Iterate over all configs/spoof_configs/*.m and run spoof scenarios

Configs (configs/spoof_configs)

Each .m file must return a struct with fields:

cfg.active    % 0 or 1
cfg.delay     % seconds
cfg.t_start   % seconds into measurement to start spoof
cfg.position  % [lat, lon, alt]
Config File Purpose
spoof_default.m Default configuration (no spoofing)
spoof_delay_test.m Test spoofing with a delay
spoof_small_offset.m Small spoofing offset (~100 m)

Tools (tools/opensource/library & demoFiles)

  • library/: GNSS‑processing functions (e.g., ProcessGnssMeas, PlotPvt, etc.).
  • demoFiles/: Provided datasets (e.g., dataset_a, dataset_b) containing .txt logs, RINEX ephemeris, etc.

Data Formats

  • Android logs: GNSSLogger .txt pseudorange logs.
    These logs contain raw GNSS measurements collected from Android devices.
  • Demo datasets: Similar .txt logs plus RINEX navigation files (hourXXXX.xx*).
    RINEX files provide satellite ephemeris data required for precise positioning.
  • Directory per dataset: Each dataset folder must contain at least one .txt file.
    Ensure that all required files are placed in the correct directory structure for processing.

How to Run

Use the original script

To use the original script, follow these steps:

  1. Navigate to the folder containing the script:

    /LabGNSS/Lab-Material/scripts/matlab/original/

  2. Open the script ProcessGnssMeasScript_original.m in MATLAB.

  3. Update the following variables in the script to match the log you want to process:

    • prFileName: Set this to the name of your GNSS log file (e.g., gnss_log_2023_03_17_16_54_04.txt).
    • dirName: Set this to the directory containing your GNSS log file.

  4. Run the script in MATLAB:

    >> ProcessGnssMeasScript_original

The script will process the specified log and generate outputs such as figures and data files. Ensure that the log file is correctly formatted and placed in the specified directory before running the script.

Initialize environment

Navigate to the Lab-Material folder using one of the following methods:

  1. Use the MATLAB command line:
>> cd /path/to/Lab-Material
  1. Use the "Browse for folder" GUI option in MATLAB to select the Lab-Material directory.

Run the InitProject script to set up all necessary paths and initialize the environment:

>> InitProject
Project paths set. Results at .../Lab-Material/results

Note

If running InitProject fails due to missing paths, manually add the required paths first to enable the script to execute.

Troubleshooting
  1. Open MATLAB and navigate to the scripts/matlab/core directory.
  2. Add the required paths manually using the addpath command: 
    >> addpath(genpath('/path/to/Lab-Material/scripts/matlab'))
  3. Alternatively, you can use the MATLAB GUI:
    • In the left panel, right-click on the scripts/matlab directory (or any subdirectory).
    • Select Add to Path -> Current Folder.
  4. Save the updated paths to ensure they persist across sessions: 
    >> savepath
  5. Retry running the InitProject script: 
    >> InitProject

If the issue persists, verify that all subdirectories under scripts/matlab are accessible and contain the necessary files.
Additionally, ensure that there are no typos in the directory paths.

Process demo datasets

>> RunDatasetAnalysis

Processes all tests for Samsung A51 and Xiaomi 11T Pro datasets.
The outputs will be saved in results/<device>/<test>/.

Single‑run demo with spoof/ADR

>> RunDemo

Runs a single demo with spoofing and ADR enabled. Modify RunDemo.m to change dataset or spoofing parameters.

Spoofing parameter sweep

>> SpoofingTest

Executes every config in configs/spoof_configs/ against the first Android log. Results under results/spoof/<config>/.

Customizing

  • Add new dataset: Place folder with .txt logs under data/<device>/gnss_logs/.
  • Add new spoof config: Drop myConfig.m in configs/spoof_configs (function returns cfg struct).
  • Adjust filters: Edit SetDataFilter.m in core/.
  • Save additional outputs: Call SaveFigures, or extend ProcessGnssMeasScript.m.

Course Tasks Mapping

Task Script(s)
1. Download & extract opensource library manual
2. Analyze raw & PVT on portal datasets; inspect plots; try filters RunDatasetAnalysis.m
3. Collect Android logs; analyze; compare open‑sky vs obstructed RunDatasetAnalysis.m
4. Estimate true position; spoof small offset; observe effects RunDemo.m, configs/spoof_configs/spoof_small_offset.m
5. Try different spoof position; propose detection strategy Add new config in configs/spoof_configs/ + SpoofingTest.m
6. Add spoof delay; study impact configs/spoof_configs/spoof_delay_test.m + SpoofingTest.m
7. (Optional) interference experiments Create new task script under tasks/, e.g. InterferenceTest.m
8. Prepare lab report (discuss Tasks 3,5,6,7) manual

Enjoy your GNSS processing workflow!