Gain and loss terms are handled differently for RAD and PCL. This should be unified in order to be consistent.
Active Radar
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if math.isnan(prop_loss): |
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if (los_ok == 1) and ( |
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fresnel_free == 1 |
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): # here we use the free space model as always |
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snr = ( |
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pt |
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+ lambda_sq |
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+ 2 * antenna_gain |
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+ t_bw_gain |
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+ dop_gain |
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+ rcs_start |
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- four_pi |
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- ktb |
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- 40 * np.log10(rng) |
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- noise_figure |
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- rf_loss |
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) |
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else: |
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return 0.0 |
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else: |
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snr_old = ( |
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pt |
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+ lambda_sq |
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+ 2 * antenna_gain |
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+ t_bw_gain |
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+ dop_gain |
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+ rcs_start |
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- four_pi |
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- ktb |
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- 40 * np.log10(rng) |
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- noise_figure |
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- rf_loss |
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) |
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snr = snr_old - 2 * ( |
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prop_loss - free_space_loss |
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) # we simply remove the extra loss found by the propagation mode |
PCL
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snr_const = ( |
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erp |
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+ 2.15 |
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+ g_proc |
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+ Rx.gain |
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- abs(Rx.losses) |
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+ 10 |
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* math.log10( |
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(c / (Tx.freq * 1e6)) ** 2 |
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/ ((4.0 * math.pi) ** 3 * k * Rx.temp_sys * Rx.bandwidth * 1000) |
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) |
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) |
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snr_extra = ( |
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snr_const |
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- snr_thresh |
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- atten_db_km * ((r_t + r_r) / 1000.0) |
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- 1 * rx_horiz_att |
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- 1 * tx_horiz_att |
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- 1 * tx_vert_att |
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- 1 * rx_vert_att |
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- 20 * math.log10(r_t * r_r) |
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) # "20 * log10( r_t*r_r ) " is the same as "10 * log10(r_t*r_t * r_r*r_r) |
