KPS – Korean Positioning System

PNT stands for Positioning, Navigation, and Timing — the three foundational pillars that enable any modern navigation or coordination system, whether in aerospace, defense, maritime, autonomous vehicles, or critical infrastructure.

Here’s a clear breakdown:

1. Positioning

This answers the question: “Where am I?”
It provides precise geographic coordinates (latitude, longitude, altitude). Typically derived from GNSS (GPS, Galileo, GLONASS, BeiDou) or INS when GNSS is unavailable.

Essential for tracking, guidance, mapping, and situational awareness.

2. Navigation

This answers: “How do I move from A to B?”
It involves determining direction, speed, and trajectory to reach a destination safely and efficiently. Includes velocity, course, and attitude (roll, pitch, yaw).

Often achieved using IMUs/INS, sensor fusion algorithms, odometry, or GNSS-based navigation.

3. Timing

This answers: “What time is it, precisely?”
Accurate, synchronized time is critical for the coordination of systems and signals. High-precision timing underpins communication networks, military systems, power grids, and GNSS itself.

Even microsecond-level errors can cause failures in comms, data links, or geolocation.

Why PNT Matters ?

PNT is at the core of every modern autonomous or guided system—whether missiles, UAVs, vehicles, USVs, AUVs, or even cellphone networks. When GNSS is degraded or denied, inertial systems (IMU/INS) become the backbone of resilient PNT.

GPS (Global Positioning System) works by using a constellation of satellites, precise timing, and trilateration to determine your position anywhere on Earth.

Here’s the simplest clear explanation:

1 – Satellites broadcast signals

About 30 GPS satellites orbit Earth, each continuously transmitting:
– Its exact position in space
– The exact time the signal was sent (using atomic clocks)

These signals travel at the speed of light.

2 – Your receiver measures travel time

A GPS receiver (in your phone, drone, INS, etc.) picks up signals from multiple satellites.

By measuring how long each signal took to arrive, it computes the distance:

               distance = speed of light × travel time

3 – Trilateration computes your location

To find your position, the receiver uses trilateration (not triangulation):

• With 1 satellite → you could be anywhere on a sphere
• With 2 satellites → circles intersect
• With 3 satellites → two possible points
• With 4 satellites → your exact 3D position + clock correction

Your receiver doesn’t have an atomic clock, so the 4th satellite is needed to solve timing errors.

4 – Corrections improve accuracy

Raw GPS has errors from:

• Atmosphere (ionosphere, troposphere)
• Satellite clock drift
• Orbit prediction errors
• Multipath reflections (signals bouncing off buildings)

To improve accuracy:

• SBAS (e.g., WAAS, EGNOS) provides real-time corrections
• RTK and PPP techniques correct errors down to centimeter-level
• INS coupling (IMU + GPS) smooths and bridges gaps during signal loss

6 – Final output

The receiver combines all data to estimate:

• Latitude
• Longitude
• Altitude
• Velocity
• Precise time

Modern GPS receivers do this dozens or hundreds of times per second.

▶︎ GPS

Signals and Frequencies

L1 C/A → 1575.42 MHz
L1C → 1575.42 MHz
L2 C → 1227.6 MHz
L2 P → 1227.6 MHz
L5 → 1176.45 MHz

▶︎ GLONASS

Signals and Frequencies

L1 C/A → 1598.0625-1609.3125 MHz
L2 C → 1242.9375-1251.6875 MHz
L2 P → 1242.9375-1251.6875 MHz
L3 → OC 1202.025

▶︎ GALILEO

Signals and Frequencies

E1 → 1575.42 MHz
E5a → 1176.45 MHz
E5b → 1207.14 MHz
E5 AltBOC → 1191.795 MHz
E6 → 1278.75 MHz

▶︎ BeiDou

Signals and Frequencies

B1I → 1561.098 MHz
B2I → 1207.14 MHz
B3I → 1268.52 MHz
B1C → 1575.42 MHz
B2a → 1176.45 MHz
B2b → 1207.14 MHz

▶︎ NAVIC

Signals and Frequencies

L5 → 1176.45 MHz

▶︎ SBAS

Signals and Frequencies

L1 → 1575.42 MHz
L5 → 1176.45 MHz

▶︎ QZSS

Signals and Frequencies

L1 C/A → 1575.42 MHz
L1 C → 1575.42 MHz
L1S → 1575.42 MHz
L2C → 1227.6 MHz
L5 → 1176.45 MHz
L6 → 1278.75 MHz