In inertial navigation, Doppler refers to the Doppler effect, which is the change in frequency of a signal due to the relative motion between a transmitter and receiver. Doppler measurements are often used to assist Inertial Navigation Systems (INS) by providing velocity data, especially in GNSS-denied environments.
How Doppler Effect is Used in INS?
Doppler Radar – Measures the Doppler shift of reflected signals to determine velocity, commonly used in aircraft and submarines.
Doppler GNSS – GNSS receivers use the Doppler shift in satellite signals to estimate speed and direction.
DVL (Doppler Velocity Log) – Used in underwater navigation, where acoustic Doppler sensors measure velocity relative to the seafloor.
Benefits of Doppler-Assisted Inertial Navigation
✔ Improves Velocity Estimation – Helps correct INS drift by providing external velocity references.
✔ Works Without GPS – Essential for submarines, aerospace, and military applications.
✔ Enhances Dead Reckoning – Reduces long-term position errors in INS-only navigation.
Limitations of Doppler in INS
✔ Requires External Signals – Doppler-based velocity measurements depend on radar, GNSS, or acoustic waves.
✔ Affected by Environmental Factors – Ocean currents, atmospheric conditions, and terrain may impact accuracy.
