1.What’ s Iridium NEXT Satellite?
Iridium Company launched its second-generation Low Earth Orbit (LEO) Iridium NEXT Satellite in 2017 and is building up a satellite communication network called Iridium Certus. This satellite features 66 applied satellites orbiting in the sky of about 780km above from the ground, giving no blind zone in the world. Compared with other fixed satellites such as MT-SAT, Inmarsat, its altitude from the ground just 1/46 is relatively low, resulting in downsized and light|er communication equipment and power consumption. It is therefore highly expected as an applied communication equipment in Rotary-wing aircraft, compact fixed-wing aircraft. The launching of all man-made satellites is tentatively completed in third quarter of 2018 and information broadcasting service for all aircrafts in Japan can start in 4/2020.
2.Scope of Iridium services
When satellite phones use Iridium satellite, there is no blind zone from the polar to equator areas, free from the impact of aircraft altitude change. It is reachable among other Iridium satellite phones, cell phones, landline phones or other company’s satellite phones. In Japan, Iridium satellite phones are provided in more than 150 aircrafts. Second-generation Iridium satellites are provided telecommunication with voice communication of 4.8Kbps apart from existing 2.8Kbps. In future, satellite phones will be applied as supporting equipment in Air Traffic Control and air traffic control zones where there is no radio coverage.
2) PTT (Push To Talk)
Iridium Push To Talk is a wireless system using satellites, which is a protocol of transmitting sounds by pushing SEND button, to IMEI-identified termical equipment PTT, available for group or area settings. A terminal equipment PTT can be connected in max 15 groups and only registered group or pre-set area terminal equipment PPT can work. Hundreds of PTT terminals can be registered in one talk group. As PTT uses Iridium satellites, there is no blind zone in open areas, except the buildings and mountainous areas. Applying stereo communication protocol with existing wireless network, it enables communication with a working team outside coverage of wireless network.
3) IP (Internet Protocol)
Iridium Certus is an Internet connection using satellite communication network, allowing access to internet via browsers or mailbox in computer via wired LAN, or to internet by tablet via wireless LAN (Wi-Fi). When connected to video equipment made by Navicom Aviation Company, it enables transmitting images of peripheral cameras, voice cameras, cabin camera to the ground. It is categorised in classes of transmit speeds and it is expected that middle class which ensures transmit speed of 352Kbps can enable transmit simple videos and data between aircraft and the ground. Transmit speed may vary depending on the structure of the aircraft.
4) SBD (Short Burst Data)
SBD (Short Burst Data) is a Packing communication using Iridium Satellites. It can receive and send short messages and aircraft position, therefore it is used as a communication protocol with D-NET plane (Natural Diaster Rescue Info Plane) made by The Japan Aerospace Exploration Agency (JAXA).Via connecting with a map information monitor (NMS-01S made by Navicom Aviation company), we can manage changing base on D-NET.