SFCW Software-Defined Radar using LabVIEW and USRP for Subsurface Sensing N.H Ardzemi (1) , F.N Mohd Isa (2) , N.F.A Malek (3) , S.Y Mohamad (4) , Rosdiadee Nordin (5) Microwave Communication & Information System Engineering (MCISE), Department of Electrical & Computer Engineering, International Islamic University Malaysia, 53100 Kuala Lumpur, Malaysia Department of Electrical, Electronic & Systems Engineering, Faculty of Engineering and Built Environment Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor ( 1 hazima.ardzemi@gmail.com, { 2 farahn, 3 norun, 4 smohamad}@iium.edu.my, 5 adee@ukm.edu.my Abstract—In this paper, we describe the experiment of a dual- channel stepped-frequency continuous wave (SFCW) radar system using LabVIEW and NI USRP N210. The step-by-step of the radar design is discussed, including the SFCW signal generation, the USRP- LabVIEW connection, and the transmit/receive process of the system. I. INTRODUCTION High-resolution radar sensors have recently become popular in remote sensing applications that require very small displacements because radar technology can interrogate and measure all weather conditions, day or night. The advance in technology has brought the existence of software-defined radar (SD Radar). It is a versatile radar system designed to overcome the limitations of fixed-purpose radar systems. SD Radar is built on the idea of replacing hardware-based components and processing with software-based components and processing. Filters, mixers, and waveform generation are all simulated on a PC or another processing device like a field- programmable gate array (FPGA). As a result, SD Radar hardware can be reused for multiple parameter configurations, making it a more versatile system with lower development costs. Stepped-Frequency Continuous Wave (SFCW) radar is being used in a wide range of applications, from measuring the micro- displacement of high-speed rail bridges in [1], to agricultural remote sensing in [2], and measuring snow depth in [3]. This is due to the SFCW system's high-range resolutions and ability to transmit high average power, both of which result in long-range/deep penetrations [4]. From the research that has been carried out by [5], [6], [7], [8], they have successfully developed SD Radar by using the SFCW system. However, in some of the research, the SFCW signal was generated by a hardware platform such as the direct digital synthesizer (DDS) board in [7] and [8], which requires extra care and extra cost for the system. Therefore, this paper will present a simulation of the dual-channel SFCW Radar system in order to alleviate the usage of the hardware platform of the SD Radar design. II. CONCEPT OF DUAL CHANNEL SFCW RADAR In an SFCW radar system, a consecutive train of sinusoidal signals ( 0 , 1 ,…, −1 ) with fixed frequency steps ( ∆ ) is transmitted towards the target, and the radar sensor will receive the reflected signals from the target. The received signals will then be processed to obtain target information. Fig. 1 illustrates the SFCW signals with their characteristics. Fig. 1. Transmitted signals and frequencies of SFCW radar in: (a) SFCW waveforms; (b) frequencies components This paper presents three stages in the design of the SFCW radar system. Stage 1 is a dual-channel SFCW signal generator [9]. The second stage is the SFCW radar transmitter design, and the last stage is the SFCW radar transceiver design. The purpose of this paper is to demonstrate the generation of SFCW signals using LabVIEW 2018 software, as well as their transmission and reception via two USRP N210 units equipped with a WBX daughterboard and monopole antennas (VERT2450). III. SFCW SD RADAR SYSTEM DESIGN SET UP AND RESULT The SFCW SD Radar is implemented in hardware using the National Instruments (NI) USRP N210 platform. Fig. 2 depicts the experimental setup for the SFCW SD Radar. Two USRP N210 units are connected to the laptop via a LAN cable and are synchronized via a MIMO cable. The USRP's IP addresses are 192.168.10.2 and 192.168.10.3, respectively. Each USRP unit represents the SFCW channel to which the two VERT2450 antennas are connected for concurrent transmission and reception. Fig. 2. Experimental setup for SFCW software-defined radar 1566 978-1-6654-9658-2/22/$31.00 ©2022 IEEE APS 2022 2022 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (AP-S/USNC-URSI) | 978-1-6654-9658-2/22/$31.00 ©2022 IEEE | DOI: 10.1109/AP-S/USNC-URSI47032.2022.9886243 Authorized licensed use limited to: University of Waterloo. Downloaded on March 16,2023 at 17:46:52 UTC from IEEE Xplore. Restrictions apply.