## Rinex2assist

<!-- prettier-ignore-start -->
[comment]: # (
SPDX-License-Identifier: GPL-3.0-or-later
)

[comment]: # (
SPDX-FileCopyrightText: 2019-2020 Carles Fernandez-Prades <carles.fernandez@cttc.es>
)
<!-- prettier-ignore-end -->

This program reads data from RINEX navigation files and generates XML files that
can be read by GNSS-SDR as Assisted GNSS data.

### Building

This program is built along with GNSS-SDR if the options
`ENABLE_UNIT_TESTING_EXTRA` or `ENABLE_SYSTEM_TESTING_EXTRA` are set to `ON`
when calling CMake:

```
$ cmake -DENABLE_SYSTEM_TESTING_EXTRA=ON ..
$ make
$ sudo make install
```

The last step is optional. Without it, you will get the executable at
`../install/rinex2assist`.

The building requires two extra dependencies: the Boost Iostreams library and
the program `uncompress`:

- The Boost Iostreams library can be installed through a package:
  - In Debian / Ubuntu: `sudo apt-get install libboost-iostreams-dev`
  - In Fedora / CentOS: `sudo yum install boost-iostreams`
  - In OpenSUSE: `sudo zypper install libboost_iostreams-devel`
  - In Arch Linux: included in `boost-libs` package.
  - In macOS: included in Macports / Homebrew `boost` package.
- The program `uncompress` is available by default in most UNIX and GNU/Linux
  systems.
  - In Fedora / CentOS: `sudo yum install ncompress`
  - In OpenSUSE: `sudo zypper install ncompress`

### Usage

The usage is as follows:

```
$ rinex2assist /path/to/RINEX_nav_file
```

The argument is mandatory (the name of the RINEX navigation file). The name
`gps_ephemeris.xml` is given to the output if GPS NAV data is fould. If the
RINEX file contains Galileo data, the corresponding `gal_ephemeris.xml` file
will be generated. The program is also able to extract parameters of the UTC and
the Ionospheric models from the RINEX header, if available. They will be called
`gps_utc_model.xml`, `gps_iono.xml`, `gal_utc_model.xml` and `gal_iono.xml`.

There are some servers available for downloading recent RINEX navigation files.
For instance:

- NASA:
  [ftp://cddis.gsfc.nasa.gov/pub/gnss/data/hourly/](ftp://gssc.esa.int/gnss/data/hourly/)
- ESA:
  [ftp://gssc.esa.int/gnss/data/hourly/](ftp://gssc.esa.int/gnss/data/hourly/)
- UNAVCO:
  [ftp://data-out.unavco.org/pub/hourly/rinex/](ftp://data-out.unavco.org/pub/hourly/rinex/)

Just make sure to pick up a recent file from a
[station near you](http://www.igs.org/network).

The program accepts either versions 2.xx or 3.xx for the RINEX navigation data
file, as well as compressed files (ending in `.gz` or `.Z`).

Examples:

```
$ rinex2assist EBRE00ESP_R_20183290400_01H_GN.rnx.gz
Generated file: gps_ephemeris.xml
Generated file: gps_utc_model.xml
Generated file: gps_iono.xml
```

and

```
$ rinex2assist EBRE00ESP_R_20183290000_01H_EN.rnx.gz
Generated file: gal_ephemeris.xml
Generated file: gal_utc_model.xml
Generated file: gal_iono.xml
```

An example of GNSS-SDR configuration using ephemeris, UTC and ionospheric model
parameters for GPS L1 and Galileo signals is shown below:

```
GNSS-SDR.AGNSS_XML_enabled=true
GNSS-SDR.AGNSS_ref_location=41.39,2.31
GNSS-SDR.AGNSS_gps_ephemeris_xml=gps_ephemeris.xml
GNSS-SDR.AGNSS_gps_iono_xml=gps_iono.xml
GNSS-SDR.AGNSS_gps_utc_model_xml=gps_utc_model.xml
GNSS-SDR.AGNSS_gal_ephemeris_xml=gal_ephemeris.xml
GNSS-SDR.AGNSS_gal_iono_xml=gal_iono.xml
GNSS-SDR.AGNSS_gal_utc_model_xml=gal_utc_model.xml
```

More info about the usage of AGNSS data
[here](https://gnss-sdr.org/docs/sp-blocks/global-parameters/#assisted-gnss-with-xml-files).