SpaceOS flight simulator with ISS orbit and telemetry
feat(space-sim,sgp4): continuous SGP4 orbit telemetry
Replace the fixed 7-frame-then-poweroff flight sim with a continuous
loop that propagates ISS orbit via SGP4 and streams real lat/lon/alt/velocity
telemetry interleaved with drifting sensor readings, health, and EVR frames.
Expose gsto (Greenwich Sidereal Time at epoch) from Sgp4.state so
consumers can call to_geodetic without replicating the GMST computation.
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+1
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bin/dune
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bin/dune
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bin/main.ml
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bin/main.ml
···
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(** P0 flight simulator — minimal init process for the flight partition.
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1. Mount devtmpfs, proc, sysfs 2. Open /dev/virtio-ports/ipc for writing 3.
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Send TM, HEALTH, EVR and ERROR frames 4. Poweroff *)
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Propagate ISS orbit via SGP4 and stream continuous telemetry *)
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let banner =
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{|
···
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let frame = Space_wire.Msg.v kind ~apid payload in
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write_frame port frame
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(* ISS TLE (epoch 2024) — good enough for a continuous demo. *)
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let iss_tle =
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{|ISS (ZARYA)
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1 25544U 98067A 24001.00000000 .00016717 00000-0 10270-3 0 9003
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2 25544 51.6400 100.0000 0007417 50.0000 310.1280 15.49560000000017|}
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+
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let rand_float lo hi = lo +. Random.float (hi -. lo)
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let rand_pick a = a.(Random.int (Array.length a))
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(* Simulate slowly-varying onboard sensors *)
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let temp = ref 22.0
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let voltage = ref 3.3
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let cpu = ref 15
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+
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let drift_sensor () =
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temp := !temp +. rand_float (-0.3) 0.3;
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temp := Float.max 10.0 (Float.min 40.0 !temp);
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voltage := !voltage +. rand_float (-0.02) 0.02;
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voltage := Float.max 3.0 (Float.min 3.6 !voltage);
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cpu := !cpu + (Random.int 5 - 2);
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cpu := max 5 (min 95 !cpu)
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let run_sim port =
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let tle =
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match Sgp4.parse_tle_string iss_tle with
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| Ok t -> t
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| Error e -> failwith (Fmt.str "TLE parse: %a" Sgp4.pp_error e)
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in
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let state =
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match Sgp4.sgp4_init tle with
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| Ok s -> s
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| Error e -> failwith (Fmt.str "SGP4 init: %a" Sgp4.pp_error e)
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in
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let gsto = Sgp4.gsto state in
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pr "SGP4 initialized: %s (epoch=%.1f)" tle.name (Sgp4.epoch_unix tle);
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(* Initial boot burst *)
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send port TM ~apid:0x100 "heartbeat:ok";
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Unix.sleepf 0.2;
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send port EVR ~apid:0x200 "IPC_LINK_UP:p1";
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Unix.sleepf 0.2;
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send port EVR ~apid:0x200 "SGP4_INIT:ok";
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Unix.sleepf 0.2;
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(* Continuous telemetry loop — 1 Hz orbit + mixed housekeeping *)
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pr "Entering continuous telemetry loop...";
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let seq = ref 0 in
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while true do
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let tsince = float_of_int !seq *. 0.1 in
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(* 0.1 min = 6s per tick *)
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incr seq;
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(* Orbit propagation *)
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(match Sgp4.propagate state tle tsince with
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| Ok (pos, vel) ->
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let speed =
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sqrt ((vel.vx *. vel.vx) +. (vel.vy *. vel.vy) +. (vel.vz *. vel.vz))
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in
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let alt =
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sqrt ((pos.x *. pos.x) +. (pos.y *. pos.y) +. (pos.z *. pos.z))
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-. 6378.135
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in
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let lat, lon, _alt_geo = Sgp4.to_geodetic pos gsto tsince in
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send port TM ~apid:0x101
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(Fmt.str "orbit:lat=%.2f,lon=%.2f,alt=%.1f,v=%.2f" lat lon alt speed)
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| Error _ -> send port ERROR ~apid:0x1FF "sgp4:propagation_error");
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Unix.sleepf 0.3;
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(* Housekeeping — rotate through different frame types *)
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drift_sensor ();
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(match !seq mod 5 with
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| 0 -> send port TM ~apid:0x100 "heartbeat:ok"
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| 1 ->
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send port TM ~apid:0x102
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(Fmt.str "sensor:temp=%.1f,voltage=%.2f" !temp !voltage)
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| 2 ->
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send port HEALTH ~apid:0x100
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(Fmt.str "cpu=%d%%,mem=%dMB,uptime=%d" !cpu
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(48 + Random.int 20)
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(!seq * 6))
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| 3 ->
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let evt =
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rand_pick
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[|
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"ORBIT_UPDATE:epoch";
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"CMD_ACK:0x42";
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"BEACON_SENT";
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"WATCHDOG_PET";
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"SENSOR_CAL:temp:done";
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|]
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in
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send port EVR ~apid:0x200 evt
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| _ ->
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let mode = rand_pick [| "nominal"; "nominal"; "nominal"; "safe" |] in
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send port TM ~apid:0x103 (Fmt.str "status:%s" mode));
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Unix.sleepf 0.7
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done
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let () =
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Random.self_init ();
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Eio_main.run @@ fun env ->
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Eio.Switch.run @@ fun _sw ->
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let fs = Eio.Stdenv.fs env in
···
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let port = Zephyr.Virtio_port.open_write ipc_name in
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Fun.protect
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~finally:(fun () -> Zephyr.Virtio_port.close port)
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(fun () ->
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send port TM ~apid:0x100 "heartbeat:ok";
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Unix.sleepf 0.5;
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send port TM ~apid:0x101 "sensor:temp=22.5";
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Unix.sleepf 0.5;
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send port HEALTH ~apid:0x100 "cpu=12%,mem=48MB,uptime=3";
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Unix.sleepf 0.5;
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send port EVR ~apid:0x200 "IPC_LINK_UP:p1";
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Unix.sleepf 0.5;
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send port TM ~apid:0x102 "status:nominal";
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Unix.sleepf 0.5;
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send port EVR ~apid:0x200 "SENSOR_CAL:temp:done";
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Unix.sleepf 0.5;
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send port ERROR ~apid:0x1FF "watchdog:timeout:recovered";
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Unix.sleepf 0.5);
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pr "Init complete. Powering off...";
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Pid1.poweroff ()
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(fun () -> run_sim port)
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end
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else begin
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pr "Not running as PID 1 (demo mode)";
···
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pr "In a real VM, this would:";
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pr " 1. Mount /proc, /sys, /dev";
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pr " 2. Open /dev/virtio-ports/ipc";
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pr " 3. Send TM, HEALTH, EVR, and ERROR frames";
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pr " 4. Poweroff"
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pr " 3. Propagate ISS orbit via SGP4";
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pr " 4. Stream continuous TM, HEALTH, EVR frames"
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end