GNSS Flashcards
What is GNSS?
Global Navigation Satellite Systems
Main GNSS systems
GPS, Galileo, GLONASS, BEIDOU
What are GNSS challenges?
Complexity
User base
Institutional control
Performance variance
GNSS challenges - Complexity - define
– control segment, satellites, modelling, signal generation
– signal path effects, receiver hardware/electronics/algorithms
– anomalies or failures can occur at any stage
GNSS challenges - user base - define
User base - multiple users globally,
GNSS challenges - institutional control - define
Institutional control - need to keep some aspects limited due to security concerns.
GNSS challenges - Performance variance - define
Performance variance - position of users and satellites in space and time
RNP - required navigation performance
GNSS vulnerabilities (16)
Signal failure
- solar flare
- tropospheric interaction
- multipaths
- jamming
Disturbance
- wanted signals affected by unwanted signals
Spoofing
Meaconing
receiver leap seconds
week number rollover
withdrawal of service
System of systems (integration)
deliberate reduction of signal
Cyber attack
near channel interference
Space debris
EMP
GNSS mitigations
Resilience - alternative approaches to roll over to should performance be degraded
Standards - internatioanlly agreed methods of developing solutions and how data can be shared for systems interoperability and confidence in users base
Testing - agreed assurance that systems work to defined criteria
Types of PNT?
eLORAN, GNSS, atomic clocks (with inertial sensors)
CNI uses of GNSS
Chemical
Civil nuclear - both timing** and **position for safety systems, monitoring and control
Communications - current low but increasing for timing due to more systems out there
Defence - wide range of applications from targeting weapons, logistics, mission planning, to pretty much any other requirement seen by other CNI sectors
Emergency services - both timing** and **position - navigation, routing, incident identification, location of lost people
Energy - both timing** and **position for safety systems, identifying new pipe routes etc, monitoring and control
Finance - timing for trading
Food - position track vehicles, pests, automated machines, yield mapping
Government - not a direct user, but needs to rely on GNSS to make the critical services it delivers work.
Health - both timing** and **position some isotopes for use are time critical from rector to use therefore depends on transport systems so show how different CNI overlaps
Space - both timing** and **position
Transport - position
Water - both timing** and **position for safety systems, locating leaks, identifying new pipe routes etc, monitoring and control
