A range accuracy and resolution enhanced 24 GHz narrow-band automotive short-range radar with cost-effective analog-front-end

Abstract

Automotive short-range radar (SRR) has been expected to provide drivers with considerable benefit on the driving of comfort, assistance, and safety. However, SRR has not been widely activated due to the various band-allocations in the world and not affordable price. Among these band-allocations, 24 GHz industry- science-medical (ISM) band has the advantages of the only harmonized band in the world and the availability of low-cost implementation using CMOS technology. But 24 GHz ISM band has narrow bandwidth compared with other ultra-wide band (UWB) allocations. Thus, it is not suitable for high range accuracy and resolution applications of SRR using conventional radars with low efficiency in bandwidth. To overcome this problem, this paper proposes the method for enhancing range accuracy and resolution. Using arbitrary high signal-to-noise ratio from favorable conditions of automotive SRR (short-range and slow update-rate), the proposed method uses the amplitude of echo signal. It is converted into digital domain with high speed sampling and N-bit resolution and then analyzed using digital signal processing to decompose over-lapped pulses caused by limited bandwidth. Through this process, the position of each pulse in overlapped pulses can be estimated precisely. Thus, range accuracy and resolution are effectively enhanced. To implement the proposed method, a high performance analog-to-digital converter (ADC) is needed to high-speed sample short echo signals with wide dynamic range. So, it degrades the cost-effectiveness of the pro-posed method. To mitigate the requirement of ADC, analog-front-end (AFE) architecture using pulse duty cycle was presented. And suitable circuits were also presented for the proposed AFE architecture in CMOS technology. The proposed method enhances band-limited range accuracy and resolution effectively using digital sig-nal processing. And the proposed AFE architecture and suitable circuits for it makes the proposed method a fea...