Implement atmosphere and dynamics data

CHANGELOG.md

@@ -15,3 +15,5 @@ This file records dated repository-level documentation and implementation change
 - `2026-03-28`: Documented professor guidance that the atmosphere model must be integrated into the simulation, must include the stratosphere branch for altitude `> 11 km`, and will not run until the `XX` placeholders are replaced.
 - `2026-03-28`: Clarified file roles so `MEMORY.md` is the durable handoff and `TODO.md` is the active execution tracker.
 - `2026-03-28`: Confirmed the stratosphere equations from `docs/Addendum to Atomosphere Model Feb 26.pdf` and recorded the required `z > 11000 m` branch for the future `getRho.m` implementation.
+- `2026-03-28`: Implemented [`code/getRho.m`](./code/getRho.m), filled the known scalar assignment constants in [`code/Interceptor_3DOF.m`](./code/Interceptor_3DOF.m) and [`code/getGuidance.m`](./code/getGuidance.m), assumed `Maz = 0 deg` for the current coplanar setup, validated `getRho.m` in Octave, and confirmed that the next blocker is the unresolved target/missile data arrays in [`code/T3dxdt.m`](./code/T3dxdt.m) and [`code/M3dxdt.m`](./code/M3dxdt.m).
+- `2026-03-28`: Transcribed the target and missile thrust, mass, area, and drag data into [`code/T3dxdt.m`](./code/T3dxdt.m) and [`code/M3dxdt.m`](./code/M3dxdt.m), fixed row/column handling in [`code/getGuidance.m`](./code/getGuidance.m), verified the dynamics helpers in Octave, and found that the remaining issue is slow end-to-end runtime in the nested `ode45` loop.

MEMORY.md

@@ -41,6 +41,9 @@ This file is the durable handoff for AI agents working in this repository. Keep
   - Compute `P11k = P0*(T/T0)^(-g/(lapserate*R))`.
   - Compute `P = P11k*exp(-g*(z - 11000)/(R*T))`.
   - Then compute `rho = P/(R*T)` and `acousticSpeed = sqrt(gamma*R*T)`.
+- Active implementation assumptions:
+  - `Maz = 0 deg` is currently assumed in `code/Interceptor_3DOF.m` to preserve the coplanar `y = 0` engagement geometry until a source document says otherwise.
+  - The target and missile thrust, mass, and drag arrays were manually transcribed from the image-based plots in `docs/Missile and Target Data for 3DOF Spring 26.pdf` on `2026-03-28`.
 - Assignment baseline confirmed from the handout:
   - Velocity pursuit guidance gain = `0.5`
   - Blind range = `2 m`
@@ -60,18 +63,20 @@ This file is the durable handoff for AI agents working in this repository. Keep
 ## Code Status
 
 - [`code/Interceptor_3DOF.m`](./code/Interceptor_3DOF.m) drives the integration loop, plotting, and CSV export.
-- [`code/T3dxdt.m`](./code/T3dxdt.m), [`code/M3dxdt.m`](./code/M3dxdt.m), and [`code/getGuidance.m`](./code/getGuidance.m) still contain `XX` placeholders.
+- [`code/getRho.m`](./code/getRho.m) now exists and implements both the lower-atmosphere model and the addendum-defined stratosphere branch for `z > 11 km`.
-- `getRho.m` is referenced by the driver and both dynamics functions, but the file is missing.
+- [`code/Interceptor_3DOF.m`](./code/Interceptor_3DOF.m) and [`code/getGuidance.m`](./code/getGuidance.m) now contain the known scalar assignment constants.
-- Because `getRho.m` does not exist yet, neither the lower-atmosphere branch nor the addendum-defined stratosphere branch for `z > 11 km` is implemented in the repo.
+- [`code/T3dxdt.m`](./code/T3dxdt.m) and [`code/M3dxdt.m`](./code/M3dxdt.m) now contain manually transcribed target/missile reference areas, thrust curves, mass curves, and drag tables.
+- [`code/getGuidance.m`](./code/getGuidance.m) now normalizes input shapes to column vectors so `M3dxdt` can call it without row/column mismatch failures.
+- Octave now evaluates `getRho.m`, `T3dxdt.m`, and `M3dxdt.m` successfully, and the full script begins integrating without placeholder errors.
+- End-to-end validation is still incomplete because the current nested `ode45` loop runs very slowly in Octave and was not observed through final plot/CSV generation within the available runtime.
 - [`code/getMD.m`](./code/getMD.m) exists and computes miss distance at the point of closest approach.
-- The missile/target data PDF appears image-based; a future agent should log the extraction method used when those tables are transcribed.
 
 ## Next Actions
 
-1. Implement `getRho.m` and integrate it into the simulation, including the required stratosphere branch for altitude `> 11 km`.
+1. Complete an end-to-end Octave validation run and confirm that the required plots and CSV files are produced.
-2. Transcribe missile and target geometry, thrust, mass, and drag data from the missile/target packet.
+2. Investigate the runtime cost of the nested `ode45` loop in [`code/Interceptor_3DOF.m`](./code/Interceptor_3DOF.m) if full validation remains too slow.
-3. Replace all remaining `XX` placeholders with sourced values.
+3. Confirm whether the temporary `Maz = 0 deg` assumption should remain.
-4. Run the MATLAB model and verify the required plots and CSV outputs.
+4. Decide whether the manually transcribed target/missile curves need a second pass for tighter fidelity.
 
 ## Update Protocol For Agents
 

README.md

@@ -42,16 +42,16 @@ The required outputs are:
 ## Current Code State
 
 - [`code/Interceptor_3DOF.m`](./code/Interceptor_3DOF.m) is the top-level driver script and writes `Ttrajectory.csv` and `Mtrajectory.csv`.
-- [`code/T3dxdt.m`](./code/T3dxdt.m) and [`code/M3dxdt.m`](./code/M3dxdt.m) contain the target and interceptor dynamics models.
+- [`code/T3dxdt.m`](./code/T3dxdt.m) and [`code/M3dxdt.m`](./code/M3dxdt.m) now include transcribed target and interceptor area, thrust, mass, and drag data from the course plots.
 - [`code/getGuidance.m`](./code/getGuidance.m) holds the guidance-law logic.
+- [`code/getRho.m`](./code/getRho.m) now implements the lower-atmosphere model and the addendum-defined stratosphere branch.
 - [`code/getMD.m`](./code/getMD.m) computes miss distance near the point of closest approach.
 
 At the moment, the repository is a partially completed assignment skeleton rather than a finished simulation:
 
-- Multiple required values are still marked as `XX`.
+- The executable `XX` placeholders have been removed from the current MATLAB code.
-- `getRho.m` is referenced by the code but is not present in the repository, so the atmosphere model has not been integrated yet.
+- The target and missile curves were manually transcribed from the image-based course plots, so those values should be treated as sourced approximations rather than machine-extracted ground truth.
-- When `getRho.m` is added, it must support both the lower-atmosphere branch and the addendum-defined stratosphere branch for `z > 11 km`.
+- The model starts running in Octave, but the nested fixed-step `ode45` loop is slow enough that end-to-end validation is still incomplete.
-- The missile/target data packet still needs to be fully transcribed into MATLAB arrays and constants.
 
 ## Working Expectations
 

TODO.md

@@ -6,19 +6,17 @@ Last updated: `2026-03-28`
 
 ## Now
 
-- [ ] Implement `getRho.m` and include the required stratosphere branch for altitude `> 11 km`.
+- [ ] Complete an end-to-end Octave validation run and confirm that the required plots and CSV files are produced.
-- [ ] Fill the known assignment constants in [`code/Interceptor_3DOF.m`](./code/Interceptor_3DOF.m) and [`code/getGuidance.m`](./code/getGuidance.m).
+- [ ] Investigate why the nested `ode45` loop is slow in Octave if the full run remains impractical.
-- [ ] Replace the current syntax-breaking `XX` placeholders that prevent the model from starting in Octave.
+- [ ] Confirm whether the temporary `Maz = 0 deg` assumption should remain.
-- [ ] Use [`docs/Addendum to Atomosphere Model Feb 26.pdf`](./docs/Addendum%20to%20Atomosphere%20Model%20Feb%2026.pdf) when implementing the `z > 11000 m` atmosphere branch.
 
 ## Blocked
 
-- [ ] Transcribe missile and target reference areas, thrust curves, mass curves, and drag tables from [`docs/Missile and Target Data for 3DOF Spring 26.pdf`](./docs/Missile%20and%20Target%20Data%20for%203DOF%20Spring%2026.pdf).
+- [ ] Full validation is currently limited by Octave runtime, not by missing source data.
 
 ## Next
 
-- [ ] Replace the remaining `XX` arrays in [`code/T3dxdt.m`](./code/T3dxdt.m) and [`code/M3dxdt.m`](./code/M3dxdt.m) with sourced data.
+- [ ] Decide whether the manually transcribed thrust, mass, and drag curves need a second pass for tighter fidelity.
-- [ ] Run [`code/Interceptor_3DOF.m`](./code/Interceptor_3DOF.m) in Octave and fix the next runtime errors.
 - [ ] Verify the required plots and inspect `Ttrajectory.csv` and `Mtrajectory.csv`.
 
 ## Done Criteria

code/Interceptor_3DOF.m

@@ -2,7 +2,7 @@
 %% Executive
 clear all; clc;
 t0 = 0; % Initial time. Target launch time.
-tCommit = XX.; % Commit time (sec)
+tCommit = 50.; % Commit time (sec)
 sigEl = 0; % Missile elevation angle standard deviation
 maxTime = 150; % estimated maximum engagement time in sec
 dt = 0.01; % integration interval (sec)
@@ -22,7 +22,8 @@ Toutput_vector(1,:)= [t0,targetState',TxDot(4:6)'];
 %% Missile initial conditions
 Mp0 = [0; 0; 0]; % Missile initial position in ENU frame (m)
 Mspeed0 = 1.e-06;% Missile initial speed in ENU frame (m/sec); must be non-zero for unit vector calculation.
-Maz = XX; Mel = XX; % Missile launch azimuth and elevation (deg).
+Maz = 0; % Assumed coplanar engagement geometry until a source doc says otherwise.
+Mel = 40; % Missile launch elevation (deg).
 Mv0 = Mspeed0*[cosd(Mel)*cosd(Maz); cosd(Mel)*sind(Maz); sind(Mel)];%initial velocity vector in ENU frame
 missileState = [Mp0; Mv0]; % Missile state vector in ENU frame (m. and m/sec.)
 Moutput_vector(1,:)= [t0,missileState', 0, 0, 0];

code/M3dxdt.m

@@ -4,19 +4,20 @@ function MxDot =  M3dxdt(Mt,missileState,targetState)
 g = 9.8066; % acceleration due to gravity
 gravity = [0; 0; -g]; % gravity vector
 diameter = 0.120; % missile diameter in m.
-S = XX; % reference area in m^2
+S = pi*(diameter/2)^2; % reference area in m^2
 [acousticSpeed,rho] = getRho(missileState);
 Mspeed = norm(missileState(4:6));
 mach = Mspeed/acousticSpeed;
-timeCurve = [XX]';  %seconds
+% Transcribed from the provided missile-data plots.
-thrustCurve = [XX]'; % Newtons
+timeCurve = [0 2.8 2.8001 11.6 11.6001 25]';  %seconds
-massCurve = [XX]'; % kg
+thrustCurve = [6200 6200 1200 1200 0 0]'; % Newtons
+massCurve = [31.8 25.1 25.1 20.9 20.9 20.9]'; % kg
 
-machCurve = [XX];
+machCurve = [0 0.5 0.7 0.9 1.0 1.05 1.1 1.2 1.5 2.0 2.5 3.0];
-dragCurve = [XX];
+dragCurve = [0.185 0.180 0.220 0.280 0.330 0.360 0.355 0.330 0.250 0.165 0.110 0.090];
 
-machCurveB = [XX];
+machCurveB = [0 0.5 0.7 0.8 0.9 1.0 1.05 1.1 1.2 1.5 2.0 2.5 3.0];
-dragCurveB = [XX];
+dragCurveB = [0.150 0.145 0.145 0.160 0.200 0.300 0.315 0.305 0.275 0.205 0.130 0.080 0.045];
 
 if(Mt<=timeCurve(end-1))
     Cd = interp1(machCurveB,dragCurveB,mach,'linear','extrap');

code/T3dxdt.m

@@ -4,20 +4,21 @@ function TxDot =  T3dxdt(t,x)
 g = 9.8066; % acceleration due to gravity
 gravity = [0; 0; -g]; % gravity vector
 diameter = 0.24; % missile diameter in m.
-S = XX; % reference area in m^2
+S = pi*(diameter/2)^2; % reference area in m^2
 [acousticSpeed,rho] = getRho(x);
 mach = norm(x(4:6))/acousticSpeed;
 
-timeCurve = [XX]';  %seconds
+% Transcribed from the provided target-data plots.
-thrustCurve = [XX]'; % Newtons
+timeCurve = [0 7.5 7.5001 45]';  %seconds
+thrustCurve = [77000 77000 0 0]'; % Newtons
 
-massCurve = [XX]'; % kg
+massCurve = [410 210 210 210]'; % kg
 
-machCurve = [XX];
+machCurve = [0 0.5 0.7 0.9 1.0 1.1 1.2 1.3 1.5 2.0 2.5 3.0 3.5 4.0];
-dragCurve = [XX];
+dragCurve = [0.40 0.40 0.43 0.60 0.75 0.87 0.86 0.80 0.74 0.60 0.50 0.44 0.40 0.39];
 
-machCurveB = [XX];
+machCurveB = [0 0.5 0.7 0.9 1.0 1.1 1.2 1.3 1.5 2.0 2.5 3.0 3.5 4.0];
-dragCurveB = [XX];
+dragCurveB = [0.31 0.31 0.34 0.47 0.62 0.78 0.77 0.72 0.64 0.50 0.40 0.34 0.30 0.27];
 
 if(t<=timeCurve(end-1))
     Cd = interp1(machCurveB,dragCurveB,mach,'linear','extrap');

code/getGuidance.m

@@ -1,19 +1,23 @@
 function [guideAccel] = getGuidance(Mt,missileState,targetState)
 % This function computes the acceleration command to the missile required to
 % intercept a target
+missileState = missileState(:);
+targetState = targetState(:);
+
 % Compute proportional navigation (PN) guidance command
 PNGain = 0; % PN guidance gain
-KVP = XX;
+terminalPNGain = 4;
-blindRng = XX; %Seeker blind range (m)
+KVP = 0.5;
-acqRng = XX; % Acquisition Range (m)
+blindRng = 2; %Seeker blind range (m)
+acqRng = 5000; % Acquisition Range (m)
 g = 9.8066; % Acceleration due to gravity (m/sec^2)
-gLimit = XX.; % Lateral acceleration limit in gees
+gLimit = 40.; % Lateral acceleration limit in gees
-relState = targetState' - missileState;
+relState = targetState - missileState;
 relRng = relState(1:3);
 relVel = relState(4:6);
 mslVel = missileState(4:6);
 % Velocity pursuit guidance
-if Mt>XX
+if Mt>0.5
     nHat = cross(mslVel,relRng);
     accelCmdVP = KVP*cross(nHat,mslVel/norm(mslVel))/norm(relRng);
 else
@@ -25,7 +29,7 @@ end
 % LOSR is line-of-sight rate
 LOSR = cross(relRng,relVel)/dot(relRng,relRng);
 if norm(relRng)<acqRng
-    PNGain = XX;
+    PNGain = terminalPNGain;
     accelCmdVP = [0; 0; 0];
 end
 %accelCmd = -PNGain*norm(relVel)*cross(relRng/norm(relRng),LOSR);
@@ -34,7 +38,6 @@ if norm(accelCmd)>gLimit*g
     accelCmd = gLimit*g*accelCmd/norm(accelCmd);
 end
 guideAccel = accelCmd + accelCmdVP;
-disp(norm(accelCmdVP));
 if norm(relRng)<blindRng
     guideAccel = [0;0;0];
 end

code/getRho.m

@@ -0,0 +1,24 @@
+function [acousticSpeed,rho] = getRho(state)
+% Compute atmospheric properties from mean sea level altitude.
+g = 9.8066; % m/sec^2
+lapserate = -0.0065; % K/m
+R = 287.05; % J/kg-K
+gamma = 1.4; % adiabatic constant for air
+z0 = 0; % mean sea level reference altitude (m)
+T0 = 288.15; % sea level temperature (K)
+P0 = 1.01325e5; % sea level pressure (Pa)
+
+z = state(3); % altitude above mean sea level (m)
+
+if z <= 11000
+    T = T0 + lapserate*(z-z0);
+    P = P0*(T/T0)^(-g/(lapserate*R));
+else
+    T = T0 + lapserate*(11000-z0);
+    P11k = P0*(T/T0)^(-g/(lapserate*R));
+    P = P11k*exp(-g*(z-11000)/(R*T));
+end
+
+rho = P/(R*T);
+acousticSpeed = sqrt(gamma*R*T);
+end