LONDON, Aug 12 (Reuters) - British satellite operator Inmarsat said it would launch a major upgrade to its L-band services to offer faster speeds and smaller low-cost terminals for its air, land and sea customers, and open up new opportunities in the Internet of Things (IOT). Called ELERA, the narrowband network will use spectrum management technology to boost speeds up to 1.7Mbps, the company said on Thursday, up to four times existing levels and beating rival global L-band networks. Inmarsat had a clear roadmap to "reinvigorate" L-band, the backbone of its low bandwidth communications and safety services for shipping, aviation and government, Chief Executive Rajeev Suri told Reuters. The investment will boost Inmarsat"s core maritime market, he said. "For Inmarsat to grow, maritime needs to return to growth," he said. "This year we will have market-leading growth and maritime should be starting to grow as well." It will be supported by the two new I-6 satellites, ordered from Airbus (AIR.PA) in 2015, with the first scheduled to launch at the end of this year and both in commercial service in the second quarter of 2023. The upgrade follows Inmarsat"s announcement of a new constellation of low earth orbit satellites last month, which it will combine with 5G mobile and its GEO satellites in a network to increase capacity in high-demand areas. read more In recent years it has focused on developing its Global Xpress high throughput broadband service, which uses the Ka band, and its European Aviation Network. Suri said the reliability and ubiquity of L-band made it particularly useful for IOT. It opens up a lot of new sectors, "and we are repositioning our enterprise business for growth," he told Reuters. "Our focus has been on mining, oil and gas, but now it is increasingly on utilities, railways and agriculture." Previously listed in London, Inmarsat was sold in 2019 to a consortium of UK-based Apax Partners, U.S.-based Warburg Pincus, Ontario Teachers" Pension Plan and the Canada Pension Plan Investment Board for $3.4 billion. Inmarsat"s competitors include U.S. company Iridium Communications (IRDM.O).