One of the world's largest American defense companies, aerospace industry and high technology Lockheed Martin emphasized that, that the US military's GPS satellite array is becoming more robust. The company's vice president of navigation systems said, that a number of upgrades in the next generation of satellites, known as GPS III Follow-On or GPS IIIF, is a "dramatic change" in anti-jamming.
GPS, which has long been considered as basic infrastructure for the military, and for civilian users, remains vulnerable to jamming and signal substitution in conflict zones and near sensitive borders. This prompts the search for additional or alternative PNT systems (positioning, navigation and time synchronization), including other satellite groupings and ground systems.
Current Space Force on-orbit modernization efforts are focused on GPS III. Service purchased 10 such satellites; nine of which have already been launched. They broadcast M-code, an encrypted military GPS signal, designed to provide a more secure and anti-jamming PNT. The urgency of expanding M-code coverage prompted the Space Force to accelerate satellite launches 7, 8 and 9 and transfer these missions from United Launch Alliance to SpaceX.
For reference: United Launch Alliance is an American private aerospace company, which specializes in providing spacecraft launch services. It is a joint venture (50/50) two giants of the aerospace industry — Lockheed Martin and Boeing. The company was founded in December 2006 year.
SpaceX (Space Exploration Technologies Corp.) is an American aerospace company, founded by Ilon Musk in 2002 year, which is currently the world leader in the number of orbital launches.
GPS IIIF builds on this foundation. According to the contract 2018 year, which provides for 22 devices, Space Force exercised options on 12 satellites, which are in various stages of production. They, similar to GPS III, will transmit M-code and have new functions, but without extending the frequency ranges beyond those, used now. The most important addition is Regional Military Protection (RMP) — regional military protection. Previous generations of GPS satellites broadcast signals in a wide pattern, covering the visible Earth at a moderate power level. The GPS III increased this power over the older Block IIFs. GPS IIIF, in turn, allows the satellite to focus the energy of the encrypted M-code in a specific region using a high-frequency directional beam.
By concentrating energy instead of global distribution, the satellite significantly increases the effective signal strength for military users in this theater of operations. A stronger signal forces the adversary to use more powerful and closer jammers, to block the service. The satellites will also carry a search and rescue payload, capable of detecting distress signals from users on land, at sea or in the air and transmit their location. This function is designed to reduce the time spent searching for people in distress.
In addition to radio frequency updates, Lockheed and the Space Force are exploring optical communication. Last GPS III satellite will carry Tesat-Spacecom SCOT80 optical terminal to demonstrate laser communication from space to Earth. The terminal supports a data transfer rate of approx 100 gigabit per second. If optical links are implemented more widely, they will operate with all-digital satellite navigation payloads, providing greater flexibility in on-orbit signal generation and control, including potential upgrades without redesigning the hardware.
Source: https://spacenews.com