Contact Graph Routing for time-varying satellite networks
fix(merlint): show file path instead of (global) for E510 issues
Add a location (file:1:0) to E510 Missing Log Source issues so the
output shows the full file path, making it easy to identify which
module needs fixing in monorepos with many similarly-named modules.
Also includes accumulated linter fixes and dune fmt formatting.
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example/tle_contacts.ml
+67
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example/tle_contacts.ml
···
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type visibility_state = { in_contact : bool; contact_start : float option }
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(** Track visibility state between a pair of satellites *)
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(** Close a contact and add it to the list. *)
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let close_contact sats visibility contacts ~rate i j time =
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match visibility.(i).(j).contact_start with
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| None -> ()
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| Some start ->
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let from = sats.(i).node in
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let to_ = sats.(j).node in
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(* Compute average OWLT (use midpoint) *)
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let mid_time = (start +. time) /. 2. in
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let owlt =
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match
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( propagate_to sats.(i).state sats.(i).tle mid_time,
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propagate_to sats.(j).state sats.(j).tle mid_time )
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with
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| Ok (p1, _), Ok (p2, _) -> light_time p1 p2
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| _ -> 0.
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in
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let contact = Cgr.Contact.v ~from ~to_ ~start ~stop:time ~rate ~owlt () in
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contacts := contact :: !contacts;
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visibility.(i).(j) <- { in_contact = false; contact_start = None }
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+
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(** Close any remaining open contacts. *)
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let close_remaining_contacts sats visibility contacts ~rate ~n ~end_time =
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for i = 0 to n - 1 do
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for j = 0 to n - 1 do
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if visibility.(i).(j).in_contact then
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close_contact sats visibility contacts ~rate i j end_time
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done
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done
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(** Generate contacts between satellites over a time window.
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@param sats List of satellites (parsed and initialized)
···
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in
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let contacts = ref [] in
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(* Close a contact and add it to the list *)
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let close_contact i j time =
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match visibility.(i).(j).contact_start with
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| None -> ()
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| Some start ->
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let from = sats.(i).node in
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let to_ = sats.(j).node in
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(* Compute average OWLT (use midpoint) *)
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let mid_time = (start +. time) /. 2. in
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let owlt =
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match
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( propagate_to sats.(i).state sats.(i).tle mid_time,
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propagate_to sats.(j).state sats.(j).tle mid_time )
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with
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| Ok (p1, _), Ok (p2, _) -> light_time p1 p2
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| _ -> 0.
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in
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let contact =
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Cgr.Contact.v ~from ~to_ ~start ~stop:time ~rate ~owlt ()
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in
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contacts := contact :: !contacts;
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visibility.(i).(j) <- { in_contact = false; contact_start = None }
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in
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-
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(* Step through time *)
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let end_time = start_time +. duration in
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let time = ref start_time in
···
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{ in_contact = true; contact_start = Some !time }
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else if (not visible) && state.in_contact then
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(* Contact ends *)
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close_contact i j !time
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close_contact sats visibility contacts ~rate i j !time
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| _ -> ()
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done
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done;
···
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time := !time +. step
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done;
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(* Close any remaining contacts *)
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for i = 0 to n - 1 do
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for j = 0 to n - 1 do
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if visibility.(i).(j).in_contact then close_contact i j end_time
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done
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done;
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-
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close_remaining_contacts sats visibility contacts ~rate ~n ~end_time;
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!contacts
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(** Parse TLEs from a multi-line string (standard TLE format) *)
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read_all []
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(** Example: Generate contacts for real Starlink satellites *)
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let example () =
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(* Load TLEs from file *)
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let tle_file = "ocaml-cgr/example/starlink.tle" in
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let tle_text =
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try load_tle_file tle_file
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with Sys_error _ ->
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Printf.eprintf "Could not load %s, using embedded TLEs\n" tle_file;
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{|STARLINK-1008
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let load_or_default_tles tle_file =
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try load_tle_file tle_file
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with Sys_error _ ->
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Printf.eprintf "Could not load %s, using embedded TLEs\n" tle_file;
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{|STARLINK-1008
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1 44714U 19074B 26034.10858321 -.00000474 00000+0 -36567-5 0 9992
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2 44714 53.1593 339.5849 0001299 80.4695 279.6453 15.31021178343579
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STARLINK-1012
···
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STARLINK-1042
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1 44747U 19074AL 26034.32583353 .00022104 00000+0 42316-3 0 9991
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2 44747 53.0433 259.4358 0003715 91.8857 268.2575 15.47997310344749|}
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+
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let print_routing_analysis plan nodes ~start_time =
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Printf.printf "\nRouting analysis:\n";
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let total_pairs = ref 0 in
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let routable_pairs = ref 0 in
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let check_route src dst =
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if Cgr.Node.equal src dst then ()
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else begin
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incr total_pairs;
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match Cgr.route plan ~src ~dst ~time:start_time with
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| Some route ->
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incr routable_pairs;
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Printf.printf " %s -> %s: %d hops, latency %.3f s\n"
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(Cgr.Node.name src) (Cgr.Node.name dst)
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(List.length (Cgr.Route.hops route))
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(Cgr.Route.latency route)
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| None ->
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Printf.printf " %s -> %s: NO ROUTE\n" (Cgr.Node.name src)
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(Cgr.Node.name dst)
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end
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in
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List.iter (fun src -> List.iter (check_route src) nodes) nodes;
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Printf.printf "\nRoutability: %d/%d pairs (%.1f%%)\n" !routable_pairs
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!total_pairs
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(100. *. Float.of_int !routable_pairs /. Float.of_int !total_pairs)
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+
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let example () =
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(* Load TLEs from file *)
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let tle_file = "ocaml-cgr/example/starlink.tle" in
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let tle_text = load_or_default_tles tle_file in
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let sats = parse_tles tle_text in
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Printf.printf "Loaded %d Starlink satellites\n" (List.length sats);
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List.iter (fun s -> Printf.printf " - %s\n" s.name) sats;
···
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(Cgr.Node.name node) from_count to_count)
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nodes;
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(* Find routes between all pairs *)
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Printf.printf "\nRouting analysis:\n";
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let total_pairs = ref 0 in
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let routable_pairs = ref 0 in
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let check_route src dst =
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if Cgr.Node.equal src dst then ()
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else begin
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incr total_pairs;
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match Cgr.route plan ~src ~dst ~time:start_time with
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| Some route ->
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incr routable_pairs;
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Printf.printf " %s -> %s: %d hops, latency %.3f s\n"
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(Cgr.Node.name src) (Cgr.Node.name dst)
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(List.length (Cgr.Route.hops route))
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(Cgr.Route.latency route)
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| None ->
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Printf.printf " %s -> %s: NO ROUTE\n" (Cgr.Node.name src)
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(Cgr.Node.name dst)
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end
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in
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List.iter (fun src -> List.iter (check_route src) nodes) nodes;
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Printf.printf "\nRoutability: %d/%d pairs (%.1f%%)\n" !routable_pairs
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!total_pairs
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(100. *. Float.of_int !routable_pairs /. Float.of_int !total_pairs)
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print_routing_analysis plan nodes ~start_time
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let () = example ()
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gen/cgr_gen.ml
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gen/cgr_gen.ml
···
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nodes;
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!contacts
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let add_ground_links contacts ~sats ~ground_stations ~duration ~rate ~owlt =
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(* Ground station links (each GS connects to first shell satellites) *)
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List.iteri
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(fun gs_idx gs ->
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let first_shell = List.nth sats 0 in
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(* Each GS has periodic contact windows with visible satellites *)
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let visible_sats = gs_idx mod List.length first_shell in
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let sat = List.nth first_shell visible_sats in
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(* Periodic visibility windows *)
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for window = 0 to 9 do
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let start = Float.of_int window *. (duration /. 10.) in
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let stop = start +. (duration /. 20.) in
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contacts :=
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Cgr.Contact.v ~from:gs ~to_:sat ~start ~stop ~rate ~owlt ()
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:: Cgr.Contact.v ~from:sat ~to_:gs ~start ~stop ~rate ~owlt ()
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:: !contacts
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done)
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ground_stations
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let constellation ~shells ~sat_per_shell ~ground_stations ~duration ~rate ~owlt
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=
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(* LEO constellation with inter-satellite and ground links *)
···
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:: !contacts)
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shell1 shell2
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done;
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(* Ground station links (each GS connects to first shell satellites) *)
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List.iteri
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(fun gs_idx gs ->
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let first_shell = List.nth sats 0 in
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(* Each GS has periodic contact windows with visible satellites *)
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let visible_sats = gs_idx mod List.length first_shell in
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let sat = List.nth first_shell visible_sats in
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(* Periodic visibility windows *)
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for window = 0 to 9 do
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let start = Float.of_int window *. (duration /. 10.) in
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let stop = start +. (duration /. 20.) in
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contacts :=
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Cgr.Contact.v ~from:gs ~to_:sat ~start ~stop ~rate ~owlt ()
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:: Cgr.Contact.v ~from:sat ~to_:gs ~start ~stop ~rate ~owlt ()
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:: !contacts
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done)
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ground_stations;
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add_ground_links contacts ~sats ~ground_stations ~duration ~rate ~owlt;
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!contacts
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let nodes n = List.init n (fun i -> Cgr.Node.v (Printf.sprintf "N%d" i))