©

RFbeam Microwave GmbH | Schuppisstrasse 7 | CH-9016 St. Gallen | www.rfbeam.ch | K-MD2 Engineering Sample | data sheet

07/2018 – Revision A | Page 9/23

Target Detection

With a set of parameters the number of raw targets

can be influenced. It can be decided how a peak over

threshold is reported. Usually an object results not

only as one peak in the range-doppler map but rather

as some peaks side by side.

Background Update (PSBU)

The running moving average is maintained for the

mean range-doppler map, which provides an expo-

nential moving average (EMA) against which each

measurement is compared. The coefficient for the

exponential decay is set using the PSBU command.

When debugging the performance, it is useful to set

the ‘Background update’ to zero so that no clut-

ter or interference is removed. It should be reset to

a typical value of 128 for normal operation. The value

sets the coefficient for the exponential moving avera-

ge against which new signals are compared. Higher

values cause the average to update more slowly so

that new signals are reported for longer.

Figure 9: Background update = 0 on the left and background update = 128 on the right

The following formula shows how the exponential

moving average filter is built:

S(t) = a . Y(t) + (1– a) . S(t – 1)

S(t) = Value of the EMA at any time period t

Y(t) = Value at a time period t

a

= 1/(background update)