add stuff for settings.h

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2026-05-15 09:10:32 -07:00
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@@ -518,62 +518,18 @@ Individual scope informations
================================== ==================================
RADAR EQUATION settings.h file suggestions:
Lets start here by mentioning the radar equation that sets the perceived strength of any /* Radar Hardware Constants */
radar echoes, no matter what kind of radar (a scope and ppi scopes) namespace ChainHome {
const float PEAK_POWER = 500000.0f; // 500 KW
Summary of radar equation: const float WAVELENGTH = 12.0f; // 12 Meters
const float ANTENNA_GAIN = 3.16f; // 5 dB expressed as linear gain
The fundamental radar equation describes how much power returns to a radar system const float PULSE_WIDTH = 0.000020f; // 20 microseconds
after bouncing off a distant target. }
Physically, it follows a "round-trip" journey
of energy: the radar transmits a signal that spreads out as a sphere (losing strength
by the square of the distance, $R^2$), hits a target that reflects a portion of that
energy (the Radar Cross Section, $\sigma$), and that reflection then spreads out
again as a second sphere on its way back (losing another factor of $R^2$).
Mathematically, this results in the received power being inversely proportional to the fourth
power of the distance ($1/R^4$), meaning that if a target moves twice as far away,
the returning signal becomes 16 times weaker. To calculate the final received power
($P_r$), you multiply the transmitted power ($P_t$) by the antenna's ability to
focus that energy (Gain, $G$) and its physical size (Aperture, $A$), then factor
in the target's reflectivity ($\sigma$) and the wavelength of the signal ($\lambda$),
all while dividing by the spreading losses $(4\pi)^3 R^4$.
$$P_r = \frac{P_t G^2 \lambda^2 \sigma}{(4\pi)^3 R^4}$$
Since we had four distinct radar types, and each one has it's own hardware loop gain
that does not change, we can set that as a constant in each radar's target handling shader set.
RADAR EQUATION STUFF FOR CHAIN HOME
For Chain Home:
Transmitter Power : 500 KW
Wavelength 12 Meters
Antenna Gain 5 dB
Pulse Width 20 microseconds
Beam Width 150 degrees (floodlight
PRF 25 HZ
Airplane acts as a half wave dipole
Sine based resonance Multiplier in target handling
// Pseudocode for Shader/Logic
float resonance = (targetLength >= wavelength * 0.4 && targetLength <= wavelength * 0.6) ? 1.5 : 1.0;
float final_sigma = base_sigma * resonance;
The 20-Mile Markers: Chain Home used crystal-controlled oscillators to create
fixed reference "pips" every 20 miles. These should be rendered as thin,
vertical spikes that never move, regardless of target sensitivity.
The "Floodlight" Effect: Because the beam is 150° wide, the A-Scope will
show every aircraft in that massive sector simultaneously. The only way to
tell them apart was the range (distance from left) and the Radiogoniometer nulling.
The Waveform Shape: For CH, the pips should be slightly "noisier" than
marine radar. Use a random jitter function in your vertex shader to
simulate the atmospheric noise floor common at 25 MHz.
namespace MarineAScope {
const float PEAK_POWER = 500000.0f; // 500 KW
const float WAVELENGTH = 0.10f; // 10 cm
const float ANTENNA_GAIN = 1000.0f; // 30 dB expressed as linear gain
}