Python library and samples for integrating with satellite Internet-of-Things modems using the Inmarsat IsatData Pro ("IDP") network.
IDP is a store-and-forward satellite messaging technology with messages up to 6400 bytes mobile-originated or 10000 bytes mobile-terminated. Messages are sent from or to a Mobile using its globally unique ID, transacted through a Mailbox that provides authentication, encryption and data segregation for cloud-based or enterprise client applications via a network Messaging API.
The first byte of the message is referred to as the Service Identification Number (SIN) where values below 16 are reserved for system use. SIN is intended to capture the concept of embedded microservices used by an application.
The second byte of the message can optionally be defined as the Message Identifier Number (MIN) intended to support remote operations within each embedded microservice with defined binary formatting. The MIN concept also supports the optional Message Definition File feature allowing an XML file to be applied which presents a JSON-tagged message structure on the network API.
- MO = Mobile Originated aka Return aka From-Mobile message sent from modem to cloud/enterprise application
- MT = Mobile Terminated aka Forward message aka To-Mobile message sent from cloud/enterprise application to modem
Upon power-up or reset, the modem first acquires its location using Global Navigation Satellite Systems (GNSS). After getting its location, the modem tunes to the correct frequency, then registers on the Inmarsat network. Once registered it can communicate on the network. Prolonged obstruction of satellite signal will put the modem into a "blockage" state from which it will automatically try to recover based on an algorithm influenced by its power mode setting.