基于DSP的數(shù)字車流量檢測雷達關(guān)鍵技術(shù)研究

摘    要

隨著智能交通系統(tǒng)在城市交通建設(shè)中的迅速發(fā)展，系統(tǒng)中的各個環(huán)節(jié)發(fā)生著越來越緊密的聯(lián)系，所采用的技術(shù)也在不斷更新，向著更準(zhǔn)更快更兼容的方向進一步的拓展。作為智能交通系統(tǒng)中不可或缺的一環(huán)-車流量檢測系統(tǒng)，也經(jīng)歷了由最初的單一的接觸式測量方式到互相輔助的混合型非接觸測量方式轉(zhuǎn)化等一系列的變化。作為一種典型的非接觸式測量器，微波車流量檢測雷達具有優(yōu)良的特性，使用方式簡便，其應(yīng)用前景十分廣闊。 

本文以調(diào)頻連續(xù)波體制下的雷達工作原理以及微波車流量檢測雷達各項功能的應(yīng)用為背景，以第一代微波車流量檢測雷達功能框架為基礎(chǔ)，通過對數(shù)字雷達技術(shù)的硬件和軟件的多角度深入研究設(shè)計和改進，實現(xiàn)一個準(zhǔn)確度高，功能多樣化，可擴展可持續(xù)發(fā)展的全天候產(chǎn)業(yè)化流量檢測系統(tǒng)，并解決各種從科研產(chǎn)品過渡到工業(yè)產(chǎn)品時所面臨的問題，為系統(tǒng)產(chǎn)業(yè)化打下良好基礎(chǔ)，滿足其嵌入更廣大的智能交通系統(tǒng)所需要的各種要求。

本文首先介紹了雷達的工作原理，并對不同的雷達工作體制的原理以及應(yīng)用作了簡單的介紹。詳細介紹了如何根據(jù)實際系統(tǒng)的要求提出車流量檢測雷達系統(tǒng)的性能技術(shù)參數(shù)化要求以及該檢測系統(tǒng)的實際工作體制和工作頻段等各項指標(biāo)。

為了使整個車流量檢測系統(tǒng)使用更加方便，符合小型化的要求，大量數(shù)字化技術(shù)的運用仍是十分理想的選擇。但是在基于ARM的第一代車流量檢測雷達中[1]，其信號處理部分比較繁瑣，采用了ARM，DSP，F(xiàn)PGA等多種器件，數(shù)字板體積大，不利于與雷達前端結(jié)合，沒有充分利用器件的功能。本文針對系統(tǒng)的實際要求，基于DSP芯片實現(xiàn)雷達信號處理部分所需的全部功能，詳細介紹了DSP芯片的使用開發(fā)方案，提出了硬件及其驅(qū)動軟件的設(shè)計方法。

另一方面，車流量檢測系統(tǒng)的信號處理算法部分的設(shè)計也是保證系統(tǒng)精確度的重要因素。本文首先介紹了系統(tǒng)的原始算法結(jié)構(gòu)，然后將整個算法分割為若干模塊，針對這些不同模塊提出了各種算法改進方案。首先提出了提高信號采集模塊性能的若干算法改進，比如如何優(yōu)化選擇系統(tǒng)的采樣頻率以及歸一化頻譜變換在DSP中的必要性和應(yīng)用方法；接下來基于現(xiàn)有的目標(biāo)判定模塊提出多次判定檢測法，以便在系統(tǒng)零信號出現(xiàn)時，最大程度保證系統(tǒng)檢測概率的準(zhǔn)確度。最后闡述了一種能有效提高雷達測量精度的背景功率譜識別方法，提出并實現(xiàn)了該算法在DSP中運行的方案，詳細論述它是如何有效的提高了系統(tǒng)的檢測精度。此方法已經(jīng)在車流量檢測雷達中得到了應(yīng)用，實驗效果明顯。

在大量的實地外場實驗和各種可靠性測試后得到了很多有效的實驗數(shù)據(jù)。實驗結(jié)果較好的證明了該系統(tǒng)的可行性和優(yōu)良性，同時通過對數(shù)據(jù)的分析和評測，也發(fā)現(xiàn)了系統(tǒng)的一些問題，綜合實驗數(shù)據(jù)和測試過程中遇到的各種問題，本文首先提出了基于現(xiàn)有芯片的幾個改進方案，使用不需要CPU干涉的DMA方式產(chǎn)生雷達調(diào)治信號以及利用不同的實時時鐘中斷方式來滿足系統(tǒng)信息傳輸模塊的需求，另外還介紹了一種標(biāo)準(zhǔn)的Modbus 通信協(xié)議來提高串口傳輸數(shù)據(jù)的穩(wěn)定性和準(zhǔn)確性。然后從更換更有效的DSP芯片TMS320VC5502的角度出發(fā)，將兩款芯片進行了性能上的對比以及相應(yīng)的驅(qū)動更改方案，針對在新芯片的各項功能在重構(gòu)該系統(tǒng)提出了驅(qū)動設(shè)計的主體框架結(jié)構(gòu)。

關(guān)鍵字：車流量檢測雷達，數(shù)字雷達技術(shù)，多次判定檢測法，背景功率譜識別

Digital Radar Technique Research of Vehicle-Flux Detecting 

Radar Based on DSP

Zheng Chun

（Microelectronics and Solid Electronics）

Directed by: Yu Wen

Abstract

With the development of Intelligent Transportation Systems(ITS) in the construction of city transportation, each part of the systems interacts with each other much more closely than ever before. Meanwhile, the technologies applied in ITS have changed greatly, which are faster, more precise and compatible. The vehicle-flux detecting system, which is the key knot of the whole ITS chain, has been improved as well. The vehicle volume detector has been changed from the single touched loop to mixed untouched methods. As one typical kind of non-touch detecting instrument, microwave vehicle-flux detecting radar is of many excellent characteristics and has been widely used.

Based on the detecting principles and the various applications of the first generation microwave vehicle-flux detecting FMCW radar[1], this paper aims at the thorough research，design and improvement of the hardware and software of digital radar technologies. Furthermore, to lay solid foundations for the industrialization of the radar sets and satisfy sorts of needs when embedded into broader ITS, this paper designs and implemented an all-day flux-detecting system with high accuracy, multiple functions and continuous development. Also many kinds of practical problems met in the industrialization have been solved in this paper.

In the beginning, how the radar practically works is described in detail and different radar mechanisms and their applications are discussed. According to the requirements of the application environment of the system, how to fix the specific parameters and functions, such as the mechanism and the working frequency, are specifically introduced.

In order to minimize the detecting radar system and make it more convenient in use,

a lot of digital techniques are needed. As to the first generation of this radar system which is based on ARM, DSP and FPGA, we can see that it is very complicated and too big to be integrated with the front of radar. What’s more, most of the chips are not fully utilized. In this paper, based on DSP chips, a new system to implement all the required and additional functions are designed. The developing scheme of the DSP chip is discussed and the architectures of the hardware and software are proposed.

On the other side, the designs of the arithmetic of the system are also essential which can guarantee the detecting accuracy. In chapter four, the original arithmetic structure is divided into several smaller modules. As to each module, the improving methods are presented and proved by reasoning and calculating. In the signal sampling module, the optimization of the sampling frequency is realized and the normalized frequency transition is implemented in DSP. Additionally, in the target-judgment module，multi-judgment detecting method is successfully applied so as to get rid of the consequences of zero signal and make the judgment of target cars more precise. Finally, a recognizing method of background power spectrum is introduced as well as the reason why it significantly improves the detecting accuracy. Also it has been transplanted into DSP and proved effective through a large amount of experiments.

The results of field experiments and reliability tests indicate that this microwave vehicle-flux detecting radar is efficient and has good performances. In the meanwhile, through the analysis and test of the experimental datas, some disadvantages have been found. Therefore, several plans based on the existed chips to improve this system are discussed such as the generation of moduling signals by DMA, the application of RTC interrupt and the Modbus protocols in the communication module. In the end, the system is reconstructed based on TMS320VC5502, for its advantages that can’t be derived in TMS320VC5416.

Key words: vehicle-flux detecting radar, digital radar technique， Multi-judgment detecting method, recognizing method of background power spectrum

目    錄

摘    要 I

Abstract III

目    錄 I

第1章 緒 論 1

1.1 智能交通系統(tǒng)概述 1

1.2 車流量檢測系統(tǒng)的研究現(xiàn)狀和性能比較 1

1.2.1 車流量檢測器的常用類型 2

1.2.2 微波車流量檢測器的優(yōu)良特性 3

1.3 數(shù)字技術(shù)在雷達系統(tǒng)中的應(yīng)用 3

1.4 本文主要內(nèi)容簡介 4

第2章 車流量檢測雷達系統(tǒng)總體設(shè)計 6

2.1 車流量檢測雷達的基本工作原理 6

2.1.1 車流量檢測雷達工作頻段及體制 6

2.1.2 車流量檢測雷達工作原理 7

2.1.3 車流量檢測雷達的功能 8

2.2 基于DSP的車流量檢測雷達系統(tǒng)設(shè)計方案 9

2.2.1 系統(tǒng)硬件設(shè)計方案 9

2.2.2 系統(tǒng)軟件設(shè)計方案 11

2.3 本章小結(jié) 12

第3章 車流量檢測雷達數(shù)字信號處理系統(tǒng)的電路功能實現(xiàn) 14

3.1 數(shù)字信號處理系統(tǒng)總體結(jié)構(gòu)設(shè)計 14

3.1.1 DSP核心處理器介紹及設(shè)計 14

3.1.2 系統(tǒng)總體結(jié)構(gòu)設(shè)計 15

3.2 采樣模塊設(shè)計 17

3.2.1 采樣電路設(shè)計 17

3.2.2 采樣驅(qū)動軟件設(shè)計 18

3.3 雷達調(diào)制信號產(chǎn)生模塊的設(shè)計 21

3.3.1 調(diào)頻三角波產(chǎn)生電路的設(shè)計 21

3.3.2 調(diào)頻三角波驅(qū)動軟件設(shè)計 22

3.4 通信模塊設(shè)計 26

3.4.1 雙通道串口電路設(shè)計 26

3.4.2 雙通道串口通信驅(qū)動軟件設(shè)計 30

3.5 外擴存儲模塊設(shè)計 33

3.5.1 程序存儲模塊 33

3.5.2 數(shù)據(jù)存儲模塊 36

3.6 本章小結(jié) 37

第4章 車流量檢測雷達數(shù)字信號處理系統(tǒng)算法改進與實現(xiàn) 38

4.1 車流量檢測算法中的目標(biāo)信息提取和分析方法 39

4.2 提高信號采集模塊性能的若干算法改進 41

4.3 提高目標(biāo)判定模塊性能的多次判定檢測法 47

4.4 提高車流量檢測系統(tǒng)回波信噪比的方法 50

4.5 本章小結(jié) 52

第5章 車流量檢測雷達外場實驗測試結(jié)果及系統(tǒng)改進方案 54

5.1 外場實驗測試結(jié)果 54

5.2 系統(tǒng)改進方案 58

5.2.1 系統(tǒng)功能優(yōu)化及擴展 58

5.2.2 基于TMS320VC5502的系統(tǒng)改進方案 64

5.3 本章小結(jié) 66

第6章 總結(jié)和展望 67

6.1 總結(jié) 67

6.2 展望 68

參考文獻 69