tdoa++ - Time-Difference of Arrival (TDOA) in C++

This is a small library tdoapp that solves the TDOA equations in 3 different ways:

• Exact solution. Based on Fang's algorithm, when the number of receivers is 3.
• Least Squares. When the number of sensors > 3
• Non-Linear Least Squares. It uses the ceres-solver's primitives to solve the nonlinear problem of the TDOA equations.

Note: This work is preliminary and it's missing a bit of functionality.

Requirements

You'll need a few libraries to compile this software:

• Eigen (version 3.3)
• Ceres-Solver (version 2.0+)
• GTest (Optional, for tests)
• nlohmann (Optional, for TdoaCLI utility)
• Boost (Optional, for TdoaCLI utility)
• Drogon (Optional, for TdoaRest webserver). This requires manual installation. Please refer to their official documentation for the steps to build it in your platform.

To install them you can use the following commands.

Linux

On Debian-based systems:

sudo apt install libeigen3-dev libceres-dev libgtest-dev libboost-dev nlohmann-json3-dev

On Arch Linux and derivatives:

sudo pacman -Syyu eigen ceres-solver gtest boost nlohmann-json

MacOS

If you have homebrew installed:

brew install eigen ceres-solver googletest boost nlohmann-json

Building

Inside the root directory, you can build the package by running:

mkdir build && cd build
cmake .. -DBUILD_TESTS={ON,OFF(Default)} -DBUILD_EXECUTABLES={ON(Default),OFF}
make -j$nproc

If you build with test support, you can run the tests by issuing this command:

ctest

Running the executables

TdoaCLI

After building, you will find the executable in build/src/TdoaCLI with the following options:

TdoaCLI. Command-Line utility to solve TDOA problems.
Allowed options::
  -h [ --help ]                 produce help message
  -r [ --receiver ] arg         JSON file with receiver positions & timestamps
  -m [ --method ] arg (=1)      Method to use (1: linear, 2: nonlinear).
                                Default: 1
  -o [ --output ] arg (=stdout) Where to dump the output: (stdout or file)

You will need a file with the receivers and timestamps. The format is as specified in templates/receiver-template.json.

TdoaRest

The TdoaRest interface runs as a webserver (based on the Drogon framework) which by default will listen on http://localhost:8095/locate. The whole list of options is:

TdoaCLI. Command-Line utility to solve TDOA problems.
Allowed options::
  -h [ --help ]                        produce help message
  -p [ --port ] arg (=8095)            Port number
  -i [ --ip-address ] arg (=0.0.0.0)   IP address to listen to
  -e [ --api-endpoint ] arg (=/locate) Where to create the localization API
                                       endpoint
  -l [ --log-path ] arg (=/tmp)        Logging path
  -t [ --thread-num ] arg (=8)         Number of threads for the server

To test that it's working, you may use the curl command and execute a POST request as follows:

curl -s -X POST "http://localhost:8095/locate"  -H 'Content-Type: application/json' -d @templates/server-template.json

Note that you need to provide a JSON file with the format defined in templates/server-template.json.

Docker Images

Docker images are available for architectures amd64 and aarch64. You can run them as:

docker run -p 8095:8095 -d yagoliz/tdoapp