diff --git a/README.md b/README.md
index a2cdb0062c5d02bc84e05ada62101a460c20525a..f15f5e33a54b75df3792ebb4589da6d2767db293 100644
--- a/README.md
+++ b/README.md
@@ -4,12 +4,59 @@
Another localisation packet protocol to send/receive localisation data over networks.
+## Details
+
+LocaPack is an implementation of the locapack protocol used to send or receive various localisation data over wired and wireless networks.
+
+LocaPack enables the transport of:
+- universal GNSS localisation coordonates such as latitude/longitude data,
+- locally referenced localisations, such as {x,y} positions in an indoor environment,
+- inter-node proximity information such as ranging data.
+
+Some extra features are also avalable, such as:
+- automatic mapping/translation of coordonates between universal GNSS/locally referenced localisations,
+- movement_id, that enables extra movement information based on another sensor (typically a local accelerometer),
+- packet sequence numbering and local timestamping, to track positions and detect missing information,
+- message hashing, to send shorter but incomplete payloads, to respect privacy.
+
+Several implementations are available:
+- Embedded: C++ class (Arduino library)
+- Infrastrucure/IoT: Node-RED palette
+- Portable: python
+
+A Json description of the messages is also available.
+
## Implementation
+Implementation status:
+
+- Arduino: encode/decode header, encode/decode universal GNSS packets ; example sketch with GPS receiver.
+- Node-RED: decode header, decode universal GNSS packets
+
### Arduino
+LocaPack is available as an Arduino library, to produce or decode locapack messages.
+
+#### Installation
+
+1. Clone the LocaPack project,
+1. Copy the `Arduino/LocaPack` directory into the libraries directory (typically `~/Arduino/libraries`)
+1. Launch Arduino IDE and start with one of the examples.
+
+- tinygpsplus.ino: Make universal GNSS pakets with data from a hardware GPS receiver connected to the `Serial1` port
+
### Node-RED
+LocaPack is available as a Node-RED Palette, ie a collection of nodes to produce or decode locapack messages.
+
+
+
+#### Installation
+
+1. Clone the LocaPack project,
+1. In your Node-RED user directory, typically ~/.node-red, run: `npm install <location of node module>` where location is the path to the `nodered` folder of the git cloned repository.
+1. Restart Node-RED.
+
### JSON messages
LocaPack messages are also available in JSON. Example of a Universal GNSS localisation packet:
@@ -124,9 +171,9 @@ Transport of locally referenced 2D or 3D localisation. The "repère" is identifi
##### Payload general structure
-| 1B | 4B | 4B | 0/4B | 0/4B | 0/8B |
-|----------|-----|-----|------|-------|-------------|
-| `header` | `x` | `y` | `z` | `dop` | `repere_id` |
+| 1B | 4B | 4B | 0/4B | 0/4B | 0/8B |
+|----------|-----|-----|------|-------|-----------------|
+| `header` | `x` | `y` | `z` | `dop` | `frameofref_id` |
The `x` field is a C-type float and is mandatory.
@@ -136,19 +183,19 @@ The `z` field is a C-type float and its presence is annouced in the `header`
The `dop` field is a C-type float and its presence is annouced in the `header`
-The `repere_id` field is a 64-bit UID and its presence is annouced in the `header`
+The `frameofref_id` field is a 64-bit UID that identify the Frame of Reference ("le repère utilisé") and its presence is annouced in the `header`
##### Header
-| 1b | 1b | 1b | 5b |
-|-------------------|---------------------|----------------------------|----------|
-| `z_presence_flag` | `dop_presence_flag` | `repere_id_presence_flag` | reserved |
+| 1b | 1b | 1b | 5b |
+|-------------------|---------------------|--------------------------------|----------|
+| `z_presence_flag` | `dop_presence_flag` | `frameofref_id_presence_flag` | reserved |
The `z_presence_flag` must be set to 1 if the `z` field is present in the packet (3D localisation).
The `dop_presence_flag` must be set to 1 if the `dop` field is present in the packet.
-The `repere_id_presence_flag` must be set to 1 if the `repere_id` field is present in the packet.
+The `frameofref_id_presence_flag` must be set to 1 if the `frameofref_id` field is present in the packet.
#### Type 2 : Inter-node proximity