User Manual

File Name: 24 GHz SQ_Technical Description_Installation Guide
Date: 31. July 2013
Autoliv Document, DUPLICATION or DISCLOSURE PROHIBITED without prior written consent
6 (9)
2 Radar Waveform Description for Mitigation
Autoliv has developed a proprietary frequency hopped, pulsed, coded FMCW like waveform. The radar codes
transmit information in time and frequency and separates return information in both the doppler domain and
distance domain. A target return can be separated from a target return of another transmitter station in three ways.
1. During the frequency dwell segment of the waveform (very short, approx. 6us) the waveform is transmitted
with a coded pulse waveform. The receiver gate is only open for specific time slots. These two combine to
reduce the effect of interfering "on frequency" transmitters.
2. The waveform sweeps over a very wide bandwidth in a short period of time (1GHz in 20ms). The IF
bandwidth is very small (less than approx.. 1MHz) thus the rejection of interfering stations is very high as it
is related to the ratio of the spread bandwidth and the IF bandwidth.
3. The transmit waveform is a random frequency hop (actually a coded frequency). Thus any interfering
stations can be distinguished from the required transmitter as they do not transmit in the same coded
frequency space.
The randomness of the pulse waveform and the frequency hopping results in the overall effect that interferers are
mitigated and are suppressed to behave as noise like signals in the receiver chain. This mitigates the deleterious
effects on the signal processing chain.