galileo-osnma is a Rust implementation of the Galileo OSNMA (Open Service Navigation Message Authentication) protocol. This protocol is used by the Galileo GNSS to sign cryptographically the navigation message data transmitted by its satellites, in order to prevent spoofing. Briefly speaking, galileo-osnma can process the navigation message data and OSNMA cryptographic data and check all the cryptographic signatures against the ECDSA public key, in order to check the authenticity of the navigation data.
galileo-osnma does not require the Rust Standard library (it can be built with
no_std), allocates all its data statically on the stack, and has a relatively
small memory footprint for the data (~65 KiB if Slow MAC is used and data for 36
satellites in parallel is stored, and ~7 KiB if Slow MAC is not used and data
for only 12 satellites in parallel is stored). This makes it possible to use the
library in some embedded microcontrollers. A demo of galileo-osnma running in a
Longan nano GD32VF103 board is provided in the
osnma-longan-nano
crate. This is a RISC-V microcontroller with 128 KiB of flash and 32 KiB of RAM
that is similar to the popular STM32F103 ARM Cortex-M3 microcontroller.
The documentation for galileo-osnma is hosted in docs.rs.
The following reference documents from the Galileo system are relevant:
galileo-osnma comes with a small binary application that can read Galileo INAV
pages using the Galmon transport
protocol. This is located in
the galmon-osnma folder.
A quick way to see this working is to use the Galmon Galileo navigation data
feed, which streams from 86.82.68.237, TCP port 10000. From the galmon-osnma
folder, we can run
nc 86.82.68.237 10000 | RUST_LOG=info cargo run --release osnma-pubkey.pem
to see galileo-osnma processing the OSNMA and navigation data streamed by Galmon.
The env_logger documentation describes
how the logging information produced by this application can be configured.
The file osnma-pubkey.pem should contain the Galileo OSNMA public key. See the
section below for how to obtain the key.
Note that Galmon aggregates data from many receivers around the world, which is not the expected use case for galileo-osnma. Therefore, when running this, there can be some small problems with data or timestamps inconsistencies.
Alternatively, you can use one of the tools of Galmon with your own GNSS
receiver. For instance, an uBlox receiver can be used as
ubxtool --wait --port /dev/ttyACM0 --station 1 --stdout --galileo | RUST_LOG=info cargo run --release osnma-pubkey.pem
The OSNMA ECDSA public key needs to be obtained to run galmon-osnma and other
example applications, as well as to make full use of the library. The key can be
downloaded from the European GNSS Service Centre,
under GSC Products > OSNMA_PUBLICKEY.
It is necessary to register an account to obtain the key.
The key is downloaded in an x509 certificate. The current certificate file is
OSNMA_PublicKey_20230803105952_newPKID_1.crt. The key in PEM format, as
required by galmon-osnma can be extracted with
openssl x509 -in OSNMA_PublicKey_20230803105952_newPKID_1.crt -noout -pubkey > osnma-pubkey.pem
galileo-osnma has been usable since its first release during the public test phase of OSNMA, and now that the service phase has begun. phase of OSNMA. It can authenticate all the types of navigation data currently supported by OSNMA using the ECDSA P-256 public key. There are some features of the OSNMA protocol and some roadmap features that are not implemented yet. These are listed below.
Supported features:
Unsupported features:
Roadmap features. These are not features of OSNMA itself, but will add to the functionality and usability of galileo-osnma:
Rust 1.65 or higher.
Minimum supported Rust version can be changed in the future, but it will be done with a minor version bump.
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