$f_L$$, f_U$	Start and end frequency of the FMCW waveform	Figure 3, (A1), (A5)
$\mathsf{\Delta }f$	Propagation incurred frequency shift between the transmitted and received signals	Figure 3, (1)
$T_{chirp}$	Sweep time of the FMCW waveform (PRI)	(2)
$B_{tot}$	Total system bandwidth	(2), (A5)
$\alpha$	LFM chirp rate	(2)
$f$	Electromagnetic frequency
$S_{meas}$	Target response	(3)
$T_{system}$	System transfer function	(3)
$T_{mp}$	Multipath factor	(4)
$h_s$	Height of targets (sphere) above ground	Figure 9, (4)
$h_{s0}$	The lowest above-ground height of the sphere	(12)
$h_A$	Height of the radar antenna above ground	Figure 9, (8)
$R_0, R$	Target distance to radar along the slant range	Figure 9, (1), (6), (A2)
$R_g$	Target distance to radar on the ground plane	Figure 9, (7)
$R_1$	Range distance of the ground-bounced path	Figure 9, (8)
${\mathsf{\Gamma }}_g$	Forward reflection coefficient of the ground	(6)
$c$	Speed of light in air	(6)
$f_{min}$$, f_{max}$	Frequencies corresponding to null response and peak response	(10), (11)
$Q$	Ratio of the scattered powers from targets (sphere) at two different heights	(12)
$H_{rms}$	Root mean square of the ground surface height variation	(14)
${\psi }_{gr}$	Grazing angle	(14)
$F_A$	Ament factor: scaling on the forward reflection ratio of the ground due to surface roughness	(14)
${\delta }_r$	Slant range resolution	(15), (A8)
${\delta }_a$	Azimuth resolution	(16)
$L$	Synthetic aperture length	(16)
$\mathsf{\Delta }\theta$	Beamwidth of azimuth beam integration	(16)
$D_a$	Physical aperture size of the antenna in azimuth	(17)
$\lambda$	Wavelength corresponding to electromagnetic frequency $f$	(16)
$s_{tx}$	Transmitted signal	(A1)
$w_T$	Rectangular window of width $T$	(A1)
$s_{rx}$	Received signal	(A2)
$a$	Amplitude of the received signal	(A2)
$p$	Correlation of the received signal with its expected copy	(A3)
$s_{ref}$	Reference signal	(A3)
$r$	Range parameter in the reference signal	(A3)
$P$	$\mathrm{Complex} \mathrm{envelope} \mathrm{of} \mathrm{the} \mathrm{correlation} p$	(A4)
$f_c$	Center (carrier) frequency	(A5)
$\Delta r$	Slant range bin size	(A7)
$\Delta f_{FFT}$	FFT frequency step	(A7)
$T$	Interval over which Fourier transform is taken	(A7)
$r_{max}$	Maximum unaliased range	Appendix A
$\Delta t_s$	Sampling interval of the IF signal	Appendix A
$P_{sub}$	Complex envelope of the correlation for sub-band processing	(A9)
$w_{T_{sub}}$	$\mathrm{Rectangular} \mathrm{window} \mathrm{of} \mathrm{width} T_{sub}$	(A9)
$f_{csub}$	Center frequency for a sub-band	(A9), (A10)
$f_l$$, f_u$	Lower and upper frequencies for a sub-band	(A10)
$T_{sub}$	Chirp duration corresponding to a sub-band	(A11)
$B_{sub}$	Sub-band bandwidth	(A11)
$t_{csub}$	Temporal center of a sub-band chirp	(A11)
${\delta }_{r sub}$	Slant range resolution corresponding to a sub-band	(A12)