Collision Avoidance Maneuver design for conjunction assessment
Test Cam.avoid with synthetic CDM
New test constructs a realistic CDM (ISS-like conjunction, crossing
orbits at 10.86 km/s, 100m miss, 30m/100m sigma) and calls Cam.avoid
with 6-hour lead time. Validates Pc is reduced below 1e-5 threshold.
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test/test_cam.ml
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test/test_cam.ml
···
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if ratio > 0.1 then
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Alcotest.failf "huge sigma: burn should barely change Pc, ratio=%e" ratio
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(* Test Cam.avoid with a synthetic CDM *)
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let test_avoid_cdm () =
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let zero_cov : Cdm.covariance =
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{
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cr_r = 900.0;
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ct_r = 0.0;
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ct_t = 10000.0;
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cn_r = 0.0;
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cn_t = 0.0;
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cn_n = 900.0;
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}
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in
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let mk_state px py pz vx vy vz : Cdm.state_vector =
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{ pos = { x = px; y = py; z = pz }; vel = { x = vx; y = vy; z = vz } }
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in
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let mk_obj id state : Cdm.object_data =
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{
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id;
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met_criteria = true;
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state;
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local = { x = 0.0; y = 0.0; z = 0.0 };
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cov = zero_cov;
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velocity_cov = None;
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density_forecast_uncertainty = None;
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screening_data_source = None;
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dcp_sensitivity_vector_position = None;
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dcp_sensitivity_vector_velocity = None;
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user_defined = None;
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filename = "";
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metadata = None;
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od_params = None;
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physical = None;
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}
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in
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let cdm : Cdm.t =
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{
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run_id = 1;
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conj_id = 1;
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obj1 = mk_obj 25544 (mk_state (-2974.0) 2974.0 5307.0 (-5.43) (-5.43) 0.0);
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obj2 = mk_obj 99999 (mk_state (-2974.05) 2974.05 5307.05 5.43 5.43 0.0);
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min_range = 0.1;
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rel_velocity = 10.86;
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probability = 1e-3;
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dilution = 1;
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miss_distance = 0.1;
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epoch = "2026-01-01T00:00:00.000";
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jdate = 2461041.5;
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header = None;
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relative_metadata = None;
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}
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in
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match Cam.avoid cdm ~dt:21600.0 with
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| None ->
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(* If already safe, that's fine — check Pc *)
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let a = Collision.assess cdm in
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Fmt.pr " Cam.avoid returned None, Pc = %e (%a)\n" a.pc Collision.pp_risk
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(Collision.risk_level a)
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| Some result ->
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Printf.printf " Cam.avoid: burn %.4f m/s, Pc %e -> %e\n" result.delta_v
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result.pc_before result.pc_after;
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Alcotest.(check bool)
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"Pc reduced" true
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(result.pc_after < result.pc_before);
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Alcotest.(check bool) "Pc below threshold" true (result.pc_after <= 1e-5)
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let suite =
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( "cam",
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[
···
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Alcotest.test_case "zero_dt" `Quick zero_dt;
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Alcotest.test_case "very_small_sigma" `Quick very_small_sigma;
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Alcotest.test_case "very_large_sigma" `Quick very_large_sigma;
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Alcotest.test_case "avoid_cdm" `Quick test_avoid_cdm;
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] )