STL is a new satellite-based time and location service for augmenting GPS to combat jamming and spoofing. Its higher power signal opens the possibility to sync indoor synchronization and timing systems without the need for a rooftop antenna system.
2. • New signal available today
• Broadcast on the Iridium sats
• >30 dB stronger than GPS
• Higher jamming and
interference resistance
• Operates indoors
• Encrypted signal
• Inherently anti-spoof
• Subscription based service
• Available for civilian use
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STL – Satellite Time & Location Signal
from
The Ideal method for augmenting GPS to combat jamming and spoofing
Copyright Orolia January 2017
3. Iridium STL
66 Iridium Satellites
Global coverage
500 mile altitude
1000x stronger
than GPS
24 GPS Satellites
Global coverage
12,500 mile altitude
25x further away
GPS
from
Copyright Orolia January 2017
4. Signal Comparison to GPS
GPS SPS L1 STL
Timing accuracy to UTC ~20 ns ~200 ns
Positioning accuracy ~3 meters 30-50 meters
Time ToFirst Fix -- Timing ~100 seconds ~few seconds
Time ToFirst Fix -- Positioning ~100 seconds ~10 minutes
Anti-spoofing No, only for military use Yes, encrypted signal
Coverage Global Global
Availability Outdoors With view of horizon to get
accurate position with low DOP
Limited view of sky lengthens
convergence time
Availability Indoors No Yes: 30 – 40 dB stronger
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5. • Re-purposed paging channels
• 1620 MHz band, 25 KHz
channel, QPSK
• Spread Spectrum coded
signal, 90 msec frame, ~1.4
sec burst on average
• UTC synchronized timing
• +/- 500 nsec spec
• 100-200 nsec typical
• Timing updates to a precision
local oscillator for
continuous time and
frequency sourcing
5
Timing signal - How it works
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6. Sub-microsecond Timing Worldwide
6
1 microsecond
STL Standard Deviation:
STL Max Excursion:
0.057 microseconds
0.332 microseconds
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7. • Iridium: ~100 minute orbit
• GPS: 12 hour orbit
• Encrypted signal with
subscriber keys
• Positioning determination
• Spot beam location (gross)
• Range and Doppler updates
• Convergence over minutes
• Geo-location security
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Low Earth Orbit (LEO) => Strong Signal with Spot Beams
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9. • Time Sync
• Augment GPS with an independent
stronger signal
• Anti spoof with subscriber authentication
of encrypted signal
• Deep Indoor Penetration
• No outdoor installation or cabling required
• 1000x stronger than GPS
• Trusted Location
• Security based on geo-location
Benefits
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10. Indoor Timing Solutions
• Network time synchronization currently requires GPS
• Data Centers
• Payment Card Compliance
• Secure Facilities
• GPS roof antennas are a “nightmare”
• Landlord permission / roof rights
• Zoning restrictions in major cities
• Building hazards (e.g. asbestos)
• Outdoor equipment maintenance
• Typical installation $10k + $1k/month
• Same needs apply to data centers
Building image from Greg Jacobs, Bicsi
GPS
9
STL
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11. Copyright Orolia January 2017
STL – adding Resilience & Trust to GPS
GPS
STL
Atomic
Holdover
Clock
A new service available from Spectracom
