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🔊 Sonar & Echolocation

Active sonar rotating sweep — detect submarines and fish schools by echo travel time t = 2R/c

ACTIVE SONAR — MYSIMULATOR.UK

Controls

Live Stats

000°
Bearing
0
Detected
500 m
Max range
1500
Sound m/s

Range Info

Freq: 5.0 kHz
Rmax: 500 m
Two-way: 0.667 s
Mode: Active

Legend

Sweep line (active ping)
Sweep trail (fades)
Range rings (100 m each)
Object blip (fades ~3 s)
Ship (center)

About Sonar & Echolocation

What It Demonstrates

Active sonar emits a high-frequency sound pulse that reflects off objects. The two-way travel time t = 2R/c (c = 1,500 m/s in seawater) gives range R = ct/2. Higher frequencies (20 kHz+) give better angular resolution but absorb faster — limiting detection to short ranges. The detection range formula is Rmax = R0 / √(f/f0) where R0=500 m, f0=5 kHz. Passive sonar listens without transmitting — stealthy, but range-limited by ambient noise floor.

How to Use

Watch the green sweep rotate and trigger bright blips when passing over objects. Slide frequency up to see detection range shrink — high-frequency sonar trades range for resolution. Slide sweep rate to change how quickly the screen refreshes. Switch object presets to compare fish schools (many small targets) vs. submarine (single large low-RCS target) vs. seamounts (fixed seafloor terrain). Objects beyond the max detection range are invisible.

Did You Know?

The word SONAR stands for Sound Navigation And Ranging. It was developed during World War I to detect German U-boats after the sinking of the Lusitania (1915). Modern military towed-array sonars stretch 2–3 km behind a submarine and can detect another sub at 100+ km range. Dolphins use biological sonar (echolocation) at 40–150 kHz — far beyond human hearing — and can distinguish objects as small as a golf ball from 100 m away.

About this simulation

This simulator recreates an active sonar display: a rotating sweep line emits pings and lights up bright blips wherever a target lies within range. Detection works on the two-way travel time of sound, t = 2R/c, with c fixed at 1,500 m/s in seawater, so range R = ct/2. The maximum detection range follows R = R0 / √(f/f0), with R0 = 500 m at f0 = 5 kHz, capturing the real trade-off in which higher frequencies sharpen resolution but shorten reach.

🔬 What it shows

A plan-position-indicator sonar screen with 100 m range rings, bearing markings and a fading green sweep. Objects are placed at a range and bearing; when the rotating beam passes one inside R = R0/√(f/f0) it spawns a yellow blip that fades over roughly three seconds, mimicking how echoes decay on a phosphor display.

🎮 How to use

The Frequency slider (1–20 kHz) raises pitch and shrinks the dashed detection ring. The Sweep speed slider (0.2–2 rotations per second) sets how fast the beam turns. The Object preset menu switches between a fish school of many small targets, a single large submarine with decoys, and fixed seamount terrain. Live stats report bearing, count detected, max range and two-way time.

💡 Did you know?

SONAR stands for Sound Navigation And Ranging, developed during the First World War to hunt submarines. Dolphins evolved their own biological sonar, clicking at 40–150 kHz and resolving objects as small as a golf ball from tens of metres away.

Frequently asked questions

What is active sonar and how does this simulation model it?

Active sonar transmits a sound pulse, or ping, and listens for the echo that bounces back from a target. This simulation shows that as a rotating green sweep on a circular screen; whenever the beam crosses an object within range, a blip appears at the matching range and bearing, just as a real plan-position-indicator console would draw it.

How is the range to a target calculated?

Range comes from the two-way travel time of sound using t = 2R/c, where c is roughly 1,500 m/s in seawater. Rearranged, R = ct/2, so the simulation reports the two-way time for the maximum range; at 500 m that is about 0.667 seconds for the ping to leave and return.

Why does raising the frequency shrink the detection range?

The model uses R = R0 / square root of (f/f0), with R0 = 500 m at f0 = 5 kHz. Higher-frequency sound is absorbed more strongly by water, so doubling the frequency does not double resolution for free; the dashed detection ring contracts and distant objects vanish from the screen.

What do the controls and presets actually change?

Frequency sets pitch and the detection radius, while Sweep speed changes how many rotations per second the beam makes. The Object preset swaps the targets between a scattered fish school, a single large submarine accompanied by small decoys, and a fixed arrangement of seamounts representing seafloor terrain.

Is this physically accurate?

The core relationships, t = 2R/c and the frequency-versus-range trade-off, are genuine sonar physics, and the 1,500 m/s sound speed is realistic for seawater. The numbers are simplified for clarity: it ignores thermoclines, salinity gradients, target strength variation and ambient noise, so treat it as an illustrative teaching tool rather than a tactical model.