US Navigation ConstellationLive GPS Satellite Tracker
Real-time tracking of 32 GPS navigation satellites across 6 orbital planes. Live constellation map, positioning accuracy heatmap, signal frequency explorer, quad-GNSS comparison, Selective Availability story, generation timeline, and L5 phone checker.
GPS Time
GPS time started at midnight 6 Jan 1980 and does not include leap seconds. Currently 18 seconds ahead of UTC.
Your GPS Right Now
Set your location below to see which GPS satellites are overhead right now and your estimated positioning accuracy.
Live Positioning Accuracy
This heatmap shows estimated GPS positioning accuracy based on current satellite geometry. Green areas have excellent satellite coverage with strong multi-angle geometry (low PDOP). Red areas have fewer visible satellites or poor geometry. The map updates as satellites complete their ~12-hour orbits.
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Your Location
GPS vs Galileo vs GLONASS vs BeiDou — Live
Four global navigation satellite systems operate simultaneously. This comparison shows live satellite counts visible from your location, along with key architectural differences. Most modern receivers use all four systems together for the best possible accuracy.
6-Plane Orbital Clock
The Night GPS Got 10× Better
For the first 17 years of civilian GPS, the US military deliberately degraded the signal. "Selective Availability" (SA) added intentional errors that limited civilian accuracy to approximately 100 metres — enough for basic navigation but useless for precision applications. At midnight on May 1, 2000, President Clinton ordered SA turned off. Overnight, every GPS receiver on Earth became 10 times more accurate.
The impact was immediate and transformative. Industries that had relied on expensive differential GPS systems suddenly had free, accurate positioning. The decision is estimated to have generated over $1.4 trillion in economic value since 2000 — enabling ride-hailing, precision agriculture, drone delivery, and the smartphone revolution.
GPS Generations — 1978 to Today
From the first experimental satellites in 1978 through five generations of technology, each GPS block has brought new capabilities. The constellation is currently a mix of Block IIR, IIR-M, IIF, and the newest Block III satellites.
GPS Signal Frequencies
GPS broadcasts multiple signals at different frequencies, each designed for specific users and applications. Modern satellites transmit up to 6 simultaneous signals. The newest signals (L5, L1C, M-Code) are only available on newer satellite generations.
What If GPS Went Down?
GPS is far more than navigation. Its precise timing signal underpins critical infrastructure across the global economy. A sustained GPS outage would have cascading effects that most people never consider.
Estimated annual economic value of GPS to the US economy alone: $1.4 trillion
Orbital Plane Breakdown
GPS's 32 satellites are distributed across 6 orbital planes (A–F), each separated by 60° in Right Ascension. The expandable 24-slot architecture allows additional satellites per plane for improved coverage.
Satellite counts are live from Orbital Radar's TLE database. Plane/slot assignments from USCG Navigation Center. See Types of Orbits for more on Walker constellations.
GPS Ground Segment
The GPS ground control network monitors satellite health, computes orbit corrections, and uploads navigation data. The Master Control Station at Schriever Space Force Base, Colorado, commands the entire constellation — backed by 16 monitor stations and 11 ground antennas worldwide.
Constellation Growth
From the first experimental Block I launch in 1978 through Full Operational Capability in 1995, the Selective Availability decision, and five generations of modernisation — GPS's remarkable 48-year journey.
GPS Satellite Directory
All GPS satellites currently operational, in reserve, or decommissioned. Click any NORAD ID for full orbital details on the Orbital Radar satellite directory.
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Does My Phone Support GPS L5?
GPS L5 is the newest civilian signal — it dramatically improves accuracy by enabling dual-frequency positioning. Most flagship phones since 2018 support it. Enter your phone model to check.
✓ GPS L5 supported: iPhone 15 and later · Samsung Galaxy S21 and later · Google Pixel 6 and later · Most 2021+ flagship Android devices with Qualcomm SDX65+ or Broadcom BCM4778+ chipsets.
⚠ L1 only (no L5): iPhone 14 and older · Samsung Galaxy S20 and older · Google Pixel 5 and older · Most mid-range and budget phones use single-frequency GPS.
Next GPS Launch
The final Block III satellite. After SV10, the next generation — GPS IIIF — begins launches in late 2027 with 60× anti-jam capability, search-and-rescue payload, and fully digital navigation.
GPS Jamming & Spoofing — A Growing Threat
GPS signals arrive at your receiver with less power than a light bulb viewed from 20,000 km away. This makes them vulnerable to jamming (overpowering with noise) and spoofing (broadcasting fake signals). Incidents have surged in recent years, particularly around conflict zones.
How Your Phone Actually Finds You
Your phone doesn't rely on GPS alone. Modern smartphones fuse multiple positioning sources to determine your location — each with different accuracy, speed, and power characteristics. Here's how they work together.
Your phone's location engine fuses all available sources using a Kalman filter — continuously weighing accuracy, freshness, and confidence to produce the best possible position estimate.
WAAS & SBAS — GPS Accuracy Boosters
Satellite-Based Augmentation Systems (SBAS) improve GPS accuracy from ~3 metres to under 1 metre by broadcasting real-time correction data from geostationary satellites. Different regions operate their own SBAS — all are free to use.
SBAS works by monitoring GPS signal errors from precisely surveyed ground stations, computing corrections in real time, and uplinking them to geostationary satellites that broadcast the corrections on the GPS L1 frequency. Any SBAS-capable GPS receiver can use these corrections automatically — no subscription required.
GPS Across Industries
GPS enables precision at scale across sectors most people never consider. Each industry has different accuracy requirements, from centimetre-level surveying to microsecond-level timing.
GPS Outages & Incidents
GPS is remarkably reliable — but not infallible. Software glitches, space weather, deliberate interference, and week-number rollovers have all caused notable incidents. Understanding these events explains why multi-GNSS and backup PNT systems matter.
Single vs Dual-Frequency GPS — The L5 Difference
The biggest leap in civilian GPS accuracy since Selective Availability was turned off. Dual-frequency (L1+L5) receivers can measure and cancel ionospheric delays that single-frequency receivers cannot — the single largest error source in GPS positioning.
GPS Week Rollover Countdown
GPS week numbers are stored as a 10-bit value (0–1,023). When the counter reaches 1,023 it wraps back to 0 — a "rollover." Receivers that don't account for this may jump to the wrong date. The issue primarily affects legacy embedded systems in critical infrastructure, maritime, and aviation that were programmed before the rollover date. Modern GPS III receivers and smartphone chipsets handle rollovers correctly.