High cost is a current problem with modern radar systems. Software-defined radios (SDRs) offer a possible solution for low-cost customizable radar systems. An SDR is a radio communi- cation system where, instead of the traditional radio components implemented in hardware, many of the components are implemented in software on a computer or embedded system. Although SDRs were originally designed for wireless communication systems, the firmware of an SDR can be configured into a radar system. With new companies entering the market, various types of low- cost SDRs have emerged. This thesis explores the use of a LimeSDR-Mini in a short-range radar through open software tools and custom code. The LimeSDR-Mini is successfully shown to detect targets at a short range. However, due to the instability of the LimeSDR-Mini, the consistent detection of a target is not possible. This thesis shows how the LimeSDR is characterized and how timing synchronization and instability issues are mitigated. The LimeSDR-Mini falls short of operating reliable in a radar system and other SDR boards need to be explored as viable options. Test setups using coaxial cables and test setups using antennas in an outdoor environment show the instability of the LimeSDR-Mini. The transmitter and the receiver are asynchronous. The timing difference varies slightly from run to run, which results in issues that are exacerbated in a short-range radar. The bleed-through signal is the signal leakage from the transmitter to the receiver. The bleed-through signal prevents the detection of targets at a short-range. Feed-through nulling is a signal processing technique used to eliminate the bleed-through signal so that short- range targets can be detected. The instability of the LimeSDR-Mini reduces the effectiveness of feed-through nulling techniques.



College and Department

Ira A. Fulton College of Engineering and Technology; Electrical and Computer Engineering



Date Submitted


Document Type





Software Defined Radio (SDR), Radar, Linear Frequency Modulated Continuous Wave (LFMCW), Ground Penetrating Radar (GPR), LimeSDR-Mini



Included in

Engineering Commons