SAM PULLEN, Stanford University
A: Since at least 1997, the Global Positioning System (GPS) Control Segment (CS) has issued what are known as “Notice Advisor(ies) to NAVSTAR Users” or “NANU(s).”
As originally reported in Section 3.5 of the 2001 version of the GPS SPS Performance Standard (GPS SPS PS), these provide “notification of changes in constellation operational status that affect the service being provided to GPS users, or if the U.S. Government anticipates a problem in supporting performance standards established in this document.”
The most recent 5th Edition of the GPS SPS PS [2] explains that a key purpose of NANUs is to alert GPS users of foreseeable future GPS satellite outages so that users are not surprised by them and potentially lose continuity. Specifically, Section 2.3.5 of [2] states the following:
GMV supplies a Galileo second-generation RF constellation simulator
Image: ESA
The European Space Agency has selected GMV to supply the radio-frequency constellation simulator (RFCS) for the Galileo second generation (G2G) program.
According to GMV, this is the multinational’s largest contract in Portugal.
From Portugal, GMV will lead a consortium to supply an RFCS covering both the first and second Galileo generations. The Galileo first generation (G1G), running since December 2016, consists of space infrastructure (26 satellites to date) and ground infrastructure.
Under the G2G RFCS contract, GMV teams in Portugal and Spain partnering with Orolia and Tecobit will develop an RFCS covering both Galileo generations as well as Galileo Open Service and Public Regulated Service (PRS). The RFCS will simulate the progressive deployment of the G2G with its new signals and will be key to supporting development of G2G infrastructure and testing of experimental user receivers.
IFEN GmbH announced that its NCS NOVA GNSS Simulator fully supports the simulation of Galileo Open-Service (OS) signal improvements based on the new Galileo OS SIS ICD V2.0. This is an important capability because the improved signals are not due to be broadcast until 2023, but can be incorporated now in GNSS receiver manufacturer testing regimes.
Among other updates, three new features are introduced to the I/NAV message transmitted on the Galileo E1-B signal component: Reduced Clock and Ephemeris Data (RedCED); Reed-Solomon Outer Forward Error Correction Data (FEC2); and Secondary Synchronization Pattern (SSP).
IFEN’s NCS NOVA GNSS Simulator is a high-end satellite navigation testing and R&D device, capable of multi-constellation and multi-frequency simulations for a wide range of GNSS applications.
HAS Information Note Table 2
Through the HAS, Galileo will offer a unique service with the transmission of corrections directly via Galileo satellites, allowing free high-accuracy positioning globally, for everyone.
The market for high-accuracy positioning is very dynamic, driven by various factors, including emerging applications such as autonomous vehicles and drones; technological advances such as dual-frequency chipsets for the mass-market; and the market situation, with cheap or free-of-charge augmentation services available in some countries. These factors are resulting in the “democratization” of high accuracy, according to the GSA. Democratization means becoming a more widespread commodity, rather than the exclusive domain of professional applications.