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https://github.com/paparazzi/paparazzi.git
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Pascal Brisset
84 lines
2.2 KiB
OCaml
84 lines
2.2 KiB
OCaml
(*
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* $Id$
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*
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* Basic GPS parameters simulation
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*
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* Copyright (C) 2004 Pascal Brisset, Antoine Drouin
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*
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* This file is part of paparazzi.
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*
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* paparazzi is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* paparazzi is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with paparazzi; see the file COPYING. If not, write to
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* the Free Software Foundation, 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*
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*)
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open Stdlib
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open Latlong
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type state = {
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mutable availability : bool;
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wgs84 : Latlong.geographic;
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alt : float;
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time : float;
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climb : float;
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gspeed : float;
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course : float
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}
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let climb_noise =
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let ng = Ocaml_tools.make_1st_order_noise_generator 0.9 0.1 in
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fun c -> c +. ng ()
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let state = fun pos0 alt0 ->
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let last_x = ref 0. and last_y = ref 0. and last_z = ref 0.
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and last_gspeed = ref 0. and last_course = ref 0. and last_climb = ref 0.
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and last_t = ref 0.
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and tow = float (Latlong.get_gps_tow ()) in
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fun (x, y, z) t ->
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let dt = t -. !last_t in
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if dt > 0. then begin (** Compute derivatives *)
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let dx = x -. !last_x
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and dy = y -. !last_y in
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last_gspeed := sqrt (dx*.dx +. dy*.dy) /. dt;
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last_course := norm_angle (pi/.2. -. atan2 dy dx);
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last_climb := (z -. !last_z) /. dt
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end; (** Else use previous derivatives *)
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let utm0 = utm_of WGS84 !pos0 in
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let utm = utm_add utm0 (x, y) in
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let wgs84 = of_utm WGS84 utm
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and alt = !alt0 +. z in
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last_x := x;
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last_y := y;
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last_z := z;
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last_t := t;
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let course = if !last_course < 0. then !last_course +. 2. *. pi else !last_course in
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{
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wgs84 = wgs84;
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alt = alt;
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time = t +. tow;
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climb = climb_noise !last_climb;
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gspeed = !last_gspeed;
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course = course;
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availability = true;
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}
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