1 // radio.hxx -- FGRadio: class to manage radio propagation
3 // Written by Adrian Musceac YO8RZZ, started August 2011.
5 // This program is free software; you can redistribute it and/or
6 // modify it under the terms of the GNU General Public License as
7 // published by the Free Software Foundation; either version 2 of the
8 // License, or (at your option) any later version.
10 // This program is distributed in the hope that it will be useful, but
11 // WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 // General Public License for more details.
15 // You should have received a copy of the GNU General Public License
16 // along with this program; if not, write to the Free Software
17 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
21 # error This library requires C++
24 #include <simgear/compiler.h>
25 #include <simgear/structure/subsystem_mgr.hxx>
27 #include <Main/fg_props.hxx>
29 #include <simgear/math/sg_geodesy.hxx>
30 #include <simgear/debug/logstream.hxx>
31 #include "antenna.hxx"
36 class FGRadioTransmission
40 double _receiver_sensitivity;
41 double _transmitter_power;
42 double _tx_antenna_height;
43 double _rx_antenna_height;
44 double _rx_antenna_gain;
45 double _tx_antenna_gain;
46 double _rx_line_losses;
47 double _tx_line_losses;
49 double _terrain_sampling_distance;
51 std::map<string, double[2]> _mat_database;
52 SGPropertyNode *_root_node;
53 int _propagation_model; /// 0 none, 1 round Earth, 2 ITM
54 double polarization_loss();
57 /*** Implement radio attenuation
58 * based on the Longley-Rice propagation model
59 * ground_to_air: 0 for air to ground 1 for ground to air, 2 for air to air, 3 for pilot to ground, 4 for pilot to air
60 * @param: transmitter position, frequency, flag to indicate if the transmission is from a ground station
61 * @return: signal level above receiver treshhold sensitivity
63 double ITM_calculate_attenuation(SGGeod tx_pos, double freq, int ground_to_air);
65 /*** a simple alternative LOS propagation model (WIP)
66 * @param: transmitter position, frequency, flag to indicate if the transmission is from a ground station
67 * @return: signal level above receiver treshhold sensitivity
69 double LOS_calculate_attenuation(SGGeod tx_pos, double freq, int ground_to_air);
71 /*** Calculate losses due to vegetation and urban clutter (WIP)
72 * We are only worried about clutter loss, terrain influence
73 * on the first Fresnel zone is calculated in the ITM functions
74 * @param: frequency, elevation data, terrain type, horizon distances, calculated loss
77 void calculate_clutter_loss(double freq, double itm_elev[], std::deque<string*> &materials,
78 double transmitter_height, double receiver_height, int p_mode,
79 double horizons[], double &clutter_loss);
81 /*** Temporary material properties database
82 * @param: terrain type, median clutter height, radiowave attenuation factor
85 void get_material_properties(string* mat_name, double &height, double &density);
90 FGRadioTransmission();
91 ~FGRadioTransmission();
93 /// a couple of setters and getters for convenience, call after initializing
94 /// frequency is in MHz, sensitivity in dBm, antenna gain and losses in dB, transmitter power in dBm
95 /// polarization can be: 0 horizontal, 1 vertical
96 void setFrequency(double freq, int radio);
97 double getFrequency(int radio);
98 inline void setTxPower(double txpower) { _transmitter_power = txpower; };
99 inline void setRxSensitivity(double sensitivity) { _receiver_sensitivity = sensitivity; };
100 inline void setTxAntennaHeight(double tx_antenna_height) { _tx_antenna_height = tx_antenna_height; };
101 inline void setRxAntennaHeight(double rx_antenna_height) { _rx_antenna_height = rx_antenna_height; };
102 inline void setTxAntennaGain(double tx_antenna_gain) { _tx_antenna_gain = tx_antenna_gain; };
103 inline void setRxAntennaGain(double rx_antenna_gain) { _rx_antenna_gain = rx_antenna_gain; };
104 inline void setTxLineLosses(double tx_line_losses) { _tx_line_losses = tx_line_losses; };
105 inline void setRxLineLosses(double rx_line_losses) { _rx_line_losses = rx_line_losses; };
106 inline void setPropagationModel(int model) { _propagation_model = model; };
107 inline void setPolarization(int polarization) { _polarization = polarization; };
109 /// static convenience functions for unit conversions
110 static double watt_to_dbm(double power_watt);
111 static double dbm_to_watt(double dbm);
112 static double dbm_to_microvolt(double dbm);
115 /*** Receive ATC radio communication as text
116 * transmission_type: 0 for air to ground 1 for ground to air, 2 for air to air, 3 for pilot to ground, 4 for pilot to air
117 * @param: transmitter position, frequency, ATC text, flag to indicate whether the transmission comes from an ATC groundstation
120 void receiveATC(SGGeod tx_pos, double freq, string text, int transmission_type);
122 /*** TODO: receive multiplayer chat message and voice
123 * @param: transmitter position, frequency, ATC text, flag to indicate whether the transmission comes from an ATC groundstation
126 void receiveChat(SGGeod tx_pos, double freq, string text, int transmission_type);
128 /*** TODO: receive navaid
129 * @param: transmitter position, frequency, flag
130 * @return: signal level above receiver treshhold sensitivity
132 double receiveNav(SGGeod tx_pos, double freq, int transmission_type);
134 /*** Call this function to receive an arbitrary signal
135 * for instance via the Nasal radioTransmission() function
136 * returns the signal value above receiver sensitivity treshhold
137 * @param: transmitter position, object heading in degrees (for antenna), object pitch angle in degrees
138 * @return: signal level above receiver treshhold sensitivity
140 double receiveBeacon(SGGeod &tx_pos, double heading, double pitch);