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
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RADAR EQUATION
settings.h file suggestions:
Lets start here by mentioning the radar equation that sets the perceived strength of any
radar echoes, no matter what kind of radar (a scope and ppi scopes)
Summary of radar equation:
The fundamental radar equation describes how much power returns to a radar system
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.
/* Radar Hardware Constants */
namespace ChainHome {
const float PEAK_POWER = 500000.0f; // 500 KW
const float WAVELENGTH = 12.0f; // 12 Meters
const float ANTENNA_GAIN = 3.16f; // 5 dB expressed as linear gain
const float PULSE_WIDTH = 0.000020f; // 20 microseconds
}
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
}