GNU Radio Radar Toolbox
static_target_simulator_cc.h
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1 /* -*- c++ -*- */
2 /*
3  * Copyright 2014 Communications Engineering Lab, KIT.
4  *
5  * This is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 3, or (at your option)
8  * any later version.
9  *
10  * This software is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this software; see the file COPYING. If not, write to
17  * the Free Software Foundation, Inc., 51 Franklin Street,
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19  */
20 
21 #ifndef INCLUDED_RADAR_STATIC_TARGET_SIMULATOR_CC_H
22 #define INCLUDED_RADAR_STATIC_TARGET_SIMULATOR_CC_H
23 
24 #include <gnuradio/tagged_stream_block.h>
25 #include <radar/api.h>
26 
27 namespace gr {
28 namespace radar {
29 
30 /*! Simulates the backscattering of a given signal on point targets.
31  *
32  * Implements the point scatter model. The input signal is the transmitted
33  * signal. The output signal is the received, backscattered signal, and
34  * contains one output signal per receive antenna.
35  *
36  * \section radar_target_modeling Target modeling
37  *
38  * The targets are modeled by the vectors \p range, \p velocity, \p rcs,
39  * and \p azimuth. All these vectors need to be of length H, where H
40  * describes the number of reflecting targets. The backscattered signal
41  * can either have a zero phase, or a random phase (controlled by
42  * \p rndm_phaseshift). The received signal will be the linear
43  * superposition of H signals, each of which are derived from the input
44  * signal by the following equation:
45  *
46  * \f[
47  * r_h(t) = b_h s(t - \tau_h) e^{j2\pi f_{D,h}}
48  * \f]
49  *
50  * The attenuation depends on the center frequency \f$f_C\f$, the radar
51  * cross section \f$\sigma_{\textnormal{\tiny RCS},h}\f$, the distance of the target
52  * \f$d_h\f$ and the speed of light \f$c_0\f$:
53  * \f[
54  * b_h = \sqrt{\frac{c_0^2 \sigma_{\textnormal{\tiny RCS},h}}{(4\pi)^3 d_h^4 f_C^2}}
55  * \f]
56  *
57  * The delay \f$\tau_h\f$ depends on the distance of the target:
58  * \f[
59  * \tau_h = 2\frac{d_h}{c_0}
60  * \f]
61  *
62  * The Doppler shift \f$f_{D,h}\f$ depends on the relative velocity and
63  * the center frequency:
64  * \f[
65  * f_{D,h} = 2\frac{v_{\textnormal{\tiny rel},h}}{c_0}{f_C}
66  * \f]
67  *
68  * The signals are added up to produce the total sum signal:
69  * \f[
70  * r(t) = \sum_{h=0}^{H-1} r_h(t)
71  * \f]
72  *
73  * \section radar_mimo_processing MIMO processing simulation
74  *
75  * This block has a limited capability of simulating multi-antenna
76  * reception. The \p position_rx vector determines the distance of every
77  * RX antenna from the origin (Note: The TX antenna is always in the
78  * origin). The length of the \p position_rx vector is thus also the number
79  * of output signals this block produces. For a simple, mono-static SISO
80  * radar, simply set position_rx to [0].
81  * The RX antennas are always laid out in a straight line. When multiple
82  * antennas are given, the target azimuth plays a role; an azimuth of zero
83  * is perpendicular to the line in which the RX antennas are placed.
84  *
85  * \section radar_hw_impairments Self-coupling
86  *
87  * Self-coupling describes the amount of the TX signal that is directly
88  * coupled into the RX path. When \p self_coupling is set to true,
89  * effectively, a target with zero velocity and range is added. The
90  * parameter \p self_coupling_db describes the attenuation of the
91  * self-coupling, a value of -10 means that the transmit signal is
92  * attenuated by 10 dB on the receive signal.
93  *
94  * \ingroup radar
95  */
96 class RADAR_API static_target_simulator_cc : virtual public gr::tagged_stream_block
97 {
98 public:
99  typedef std::shared_ptr<static_target_simulator_cc> sptr;
100 
101  /*!
102  * \param range Target ranges as vector (length H)
103  * \param velocity Target velocities as vector (length H)
104  * \param rcs Target RCS as vector (length H)
105  * \param azimuth Target azimuth as vector (length H)
106  * \param position_rx Position RX antennas. A value of [0] means
107  * there is one antenna, located in the origin
108  * (simple monostatic case).
109  * \param samp_rate Sample rate (samples per second)
110  * \param center_freq Center frequency (Hz)
111  * \param self_coupling_db Self coupling attenuation (dB)
112  * \param rndm_phaseshift Toggle random phaseshift on targets
113  * \param self_coupling Toggle self coupling
114  * \param packet_len Packet length key for tagged stream
115  */
116  static sptr make(std::vector<float> range,
117  std::vector<float> velocity,
118  std::vector<float> rcs,
119  std::vector<float> azimuth,
120  std::vector<float> position_rx,
121  int samp_rate,
122  float center_freq,
123  float self_coupling_db,
124  bool rndm_phaseshift = true,
125  bool self_coupling = true,
126  const std::string& len_key = "packet_len");
127 
128  virtual void setup_targets(std::vector<float> range,
129  std::vector<float> velocity,
130  std::vector<float> rcs,
131  std::vector<float> azimuth,
132  std::vector<float> position_rx,
133  int samp_rate,
134  float center_freq,
135  float self_coupling_db,
136  bool rndm_phaseshift,
137  bool self_coupling) = 0;
138 };
139 
140 } // namespace radar
141 } // namespace gr
142 
143 #endif /* INCLUDED_RADAR_STATIC_TARGET_SIMULATOR_CC_H */
#define RADAR_API
Definition: api.h:31
Definition: static_target_simulator_cc.h:97
std::shared_ptr< static_target_simulator_cc > sptr
Definition: static_target_simulator_cc.h:99
static sptr make(std::vector< float > range, std::vector< float > velocity, std::vector< float > rcs, std::vector< float > azimuth, std::vector< float > position_rx, int samp_rate, float center_freq, float self_coupling_db, bool rndm_phaseshift=true, bool self_coupling=true, const std::string &len_key="packet_len")
virtual void setup_targets(std::vector< float > range, std::vector< float > velocity, std::vector< float > rcs, std::vector< float > azimuth, std::vector< float > position_rx, int samp_rate, float center_freq, float self_coupling_db, bool rndm_phaseshift, bool self_coupling)=0
Definition: crop_matrix_vcvc.h:28