Broadband OFDM Radar System at Reduced Sampling Rates Using Frequency Combs (BORA)

使用频率梳降低采样率的宽带 OFDM 雷达系统 (BORA)

• 批准号: 467104011
• 负责人: Professor Dr.-Ing. Ahmet Ulusoy
• 金额: --
• 依托单位: Institut für Hochfrequenztechnik und Elektronik (IHE)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/467104011?language=en
• 关键词: Broadband; OFDM; Radar; System; Reduced

In the BORA project, a novel concept for the generation and processing of broadband OFDM radar signals with reduced sampling rates is to be investigated and implemented in integrated circuits. A high bandwidth is required in radar applications in order to achieve a good range resolution for the separation of closely spaced targets. In digital radar modulation schemes, such as OFDM, the challenge arises that, along with the high instantaneous bandwidth, high sampling rates are required for the digital-to-analog (DAC) and analog-to-digital converters (ADC). However, since these converters are very expensive and power hungry, alternative options are currently being investigated to enlarge the bandwidth without increasing the sampling rates. Here we propose a unique method, which is to be further developed and implemented in BORA. It is based on the mixing of a narrowband OFDM baseband signal with a frequency comb, whose frequency spacing is identical to the bandwidth of the baseband signal. The concatenation of several subbands results in a broadband OFDM radar signal that can be emitted. Here, each of the subbands results from the up-conversion of the baseband signal with one of the comb frequencies. Only some of the possible subcarriers are used in the baseband, which creates gaps in the spectrum into which the subcarriers of the remaining subbands can be inserted on the receiving side. This creates a common narrow-band frequency band that contains the information of all received subbands. After appropriate filtering, the associated signal can be sampled at the same low rate at which the baseband signal was generated in the transmitter. The interleaving of the subbands in the receiver is achieved by mixing the received signal with a second frequency comb, whose carrier spacing is slightly smaller than that in the transmitter. Since in OFDM all subcarriers are orthogonal to one another, the information of the interleaved subcarriers can be separated and the broadband radio-frequency signal can be virtually reconstructed.In the BORA project, the frequency comb OFDM radar scheme is to be further developed and requirements regarding a hardware implementation are to be derived. Based on this system analysis, a suitable hardware architecture is to be designed and implemented on an MMIC (monolithic microwave integrated circuit) at 140 GHz. Finally, with the help of the MMICs, a demonstrator is to be set up and put into operation. With its help, the results of the system analysis can be validated and, for example, the influence of different comb generation methods and forms can be examined. When successful, BORA will enable a very efficient digital high-resolution radar for fast moving targets (e.g. for crash avoidance or some industrial applications).

在BORA项目中，将研究一种新的概念，用于产生和处理具有降低采样率的宽带OFDM雷达信号，并在集成电路中实现。在雷达应用中，为了获得良好的距离分辨率以分离近距离目标，需要高带宽。在数字雷达调制方案（如OFDM）中，随着高瞬时带宽的出现，数字模拟（DAC）和模数转换器（ADC）需要高采样率，这是一个挑战。然而，由于这些转换器非常昂贵且耗电，目前正在研究在不增加采样率的情况下扩大带宽的替代方案。在此，我们提出了一种独特的方法，有待在BORA中进一步开发和实施。它基于窄带OFDM基带信号与频率梳的混合，频率梳的频率间隔与基带信号的带宽相同。几个子带的连接产生可以发射的宽带OFDM雷达信号。在这里，每个子带都是基带信号与其中一个梳频率上转换的结果。基带中只使用了一些可能的子载波，这在频谱中产生了间隙，其余子带的子载波可以插入到接收侧。这将创建一个包含所有接收子带信息的公共窄带频带。经过适当滤波后，可以以与在发射机中产生基带信号相同的低速率对关联信号进行采样。通过将接收到的信号与第二频梳混合来实现接收机中子带的交错，第二频梳的载波间距略小于发射机中的载波间距。由于OFDM中所有的子载波都是相互正交的，因此可以将交错子载波的信息分离，从而实现宽带射频信号的虚拟重构。在BORA项目中，将进一步开发频率梳OFDM雷达方案，并推导出有关硬件实现的要求。在此系统分析的基础上，在140 GHz的MMIC（单片微波集成电路）上设计并实现了合适的硬件架构。最后，在mmic的帮助下，建立了一个演示器并投入运行。在它的帮助下，可以验证系统分析的结果，例如，可以检查不同梳子生成方法和形式的影响。一旦成功，BORA将使一个非常高效的数字高分辨率雷达能够用于快速移动目标（例如用于防撞或一些工业应用）。