User's Manual Part 2

Processing Algorithms (draft)
RVP8 User’s Manual
April 2003
5–38
5.7.2 Radar System Considerations
A polarization radar is characterized by how it transmits and how it receives. For simplicity we
will assume that the radar uses horizontal and/or vertical polarization. However, other
polarization pairs could be used (e.g., right and left circular polarization).
Transmit Modes
S Fixed (horizontal or vertical)- this can be controlled by a switch or the radar can
be simply fixed to transmit a single polarization. If a switch is used, it can be a
simple slow waveguide switch rather than a fast switch (pulse-to-pulse).
S Alternating (horizontal and vertical)- in this case the radar alternates
pulse-to-pulse between horizontal and vertical. A high-power fast switch is used
to switch the polarization between the two channels.
S Simultaneous (horizontal and vertical)- horizontal and vertical are transmitted
simultaneously.
Receive Modes
S Single-channel receiver- used only for alternating transmission. The receiver
typically receives the co–polarized radiation (transmit H and receive H then
transmit V and receive V).
S Dual-channel receiver- receives two channels (H and V) simultaneously.
The table below summarizes the various transmit and receive cases and the polarization variables
that are available for each. Note that standard parameters are available for all cases (dBT, dBZ,
V and W). The RVP8 supports all of these cases.
Transmitter Type
Receiver Type Fixed H Fixed V Alternating
H&V
Simultaneous
H+V
Single-Channel Conventional
Radar
Conventional
Radar
ZDR
RHOHV
PHIDP and KDP
Not applicable
Dual-Channel LDRH
RHOH
PHIH
LDRV
RHOV
PHIV
LDRH LDRV
RHOH RHOV
PHIH PHIV
ZDR
RHOHV
PHIDP and KDP
ZDR
RHOHV
PHIDP and KDP
(STAR mode)
The fixed single -channel cases are conventional radars rather than polarization radars. The case
of simultaneous H+V transmission and a single radar does not make physical sense. The other
cases provide various polarization measurements. The fixed dual-channel cases allow the
cross-polarization LDR and the co-pol/cross-pol correlation amplitude and phase to be measured