System of Systems: DHS Receiver Improvements, Australian SBAS

DHS Spells Out Receiver Improvements

In early January, a new Department of Homeland Security (DHS) document appeared: “Improving the Operation and Development of Global Positioning System (GPS) Equipment Used by Critical Infrastructure.”

The document focuses on receivers used in critical infrastructure, with an emphasis on timing receivers. It provides owners, operators, researchers, designers and manufacturers with information to improve the security and resilience of PNT equipment across the spectrum of equipment development, deployment and use.

Specifically, its recommendations address:

• installation and operation strategies that can be implemented for current equipment,
• strategies that can result in more robust and resilient new and/or improved products based on existing technology and knowledge,
• research and development that can lead to improved future capabilities.

It introduces clear definitions of different categories of threats and hazards, including the new term “data spoofing.” It recommends some creative ways to install receive antennas, such as using decoy antennas and obscuring the location of the actual antennas being used, presumably to foil some spoofing attacks.

It also points out that modern GNSS receivers are computers, and need to be operated and maintained with good cyber hygiene, just like other computers.

The extensive list of recommended development strategies will challenge manufacturers while informing purchasers about the features they can seek in new equipment.

Implementing these recommendations will lead to increased competence — that is, equipment that is better able to accommodate imperfect or faulty inputs, intentional or not.

This document reflects the recognition that many reported problems or difficulties with GPS could be prevented or mitigated by improvements in GPS user equipment and how it is installed and operated. It is encouraging to see DHS taking steps to remedy this situation, and important that manufacturers of timing receivers, as well as critical infrastructure owners and operators that use timing receivers, follow through on these recommendations.

Also for Receiver Manufacturers

The Radio Technical Commission for Maritime Services (RTCM) has issued a paper with calculation algorithms to promote consistent BeiDou IODE and IODC computational approaches within the community.

To improve precision navigation, a second-generation SBAS will use signals from both GPS and Galileo, and dual frequencies, to achieve even greater GNSS integrity and accuracy.

Second-Generation SBAS

Geoscience Australia, an agency of the Commonwealth of Australia, will collaborate with Lockheed Martin,  Inmarsat and GMV on research to show how augmenting signals from multiple GNSS constellations can enhance positioning, navigation and timing for a range of applications.

The project aims to demonstrate how a second-generation satellite-based augmentation system (SBAS) testbed can for the first time use signals from both GPS and Galileo, as well as dual frequencies, to provide greater integrity and accuracy. Over two years, the testbed will validate applications in nine industry sectors: agriculture, aviation, construction, maritime, mining, rail, road, spatial and utilities.

Basic GNSS signals require augmentation to meet higher safety-of-life navigation requirements. The second-generation SBAS will mitigate that issue. Once the testbed is operational, basic GNSS signals will be monitored by widely distributed reference stations operated by Geoscience Australia.

A master station, installed by GMV, will collect the data, compute corrections and integrity bounds for each GNSS satellite signal, and generate augmentation messages.

A Lockheed Martin uplink antenna at Uralla, New South Wales, will send these augmentation messages to an SBAS payload hosted aboard a geostationary Earth orbit satellite, owned by Inmarsat, which rebroadcasts the augmentation messages containing corrections and integrity data to end users. The whole process takes less than six seconds.