基于DSP的數(shù)字車流量檢測(cè)雷達(dá)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(gè)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(jìn)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(cè)系統(tǒng)，也經(jīng)歷了由最初的單一的接觸式測(cè)量方式到互相輔助的混合型非接觸測(cè)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(cè)量器，微波車流量檢測(cè)雷達(dá)具有優(yōu)良的特性，使用方式簡(jiǎn)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(dá)工作原理以及微波車流量檢測(cè)雷達(dá)各項(xiàng)功能的應(yīng)用為背景，以第一代微波車流量檢測(cè)雷達(dá)功能框架為基礎(chǔ)，通過對(duì)數(shù)字雷達(dá)技術(shù)的硬件和軟件的多角度深入研究設(shè)計(jì)和改進(jìn)，實(shí)現(xiàn)一個(gè)準(zhǔn)確度高，功能多樣化，可擴(kuò)展可持續(xù)發(fā)展的全天候產(chǎn)業(yè)化流量檢測(cè)系統(tǒng)，并解決各種從科研產(chǎn)品過渡到工業(yè)產(chǎn)品時(shí)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(dá)的工作原理，并對(duì)不同的雷達(dá)工作體制的原理以及應(yīng)用作了簡(jiǎn)單的介紹。詳細(xì)介紹了如何根據(jù)實(shí)際系統(tǒng)的要求提出車流量檢測(cè)雷達(dá)系統(tǒng)的性能技術(shù)參數(shù)化要求以及該檢測(cè)系統(tǒng)的實(shí)際工作體制和工作頻段等各項(xiàng)指標(biāo)。

為了使整個(gè)車流量檢測(cè)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(yùn)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(cè)雷達(dá)中[1]，其信號(hào)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(dá)前端結(jié)合，沒有充分利用器件的功能。本文針對(duì)系統(tǒng)的實(shí)際要求，基于DSP芯片實(shí)現(xiàn)雷達(dá)信號(hào)處理部分所需的全部功能，詳細(xì)介紹了DSP芯片的使用開發(fā)方案，提出了硬件及其驅(qū)動(dòng)軟件的設(shè)計(jì)方法。

另一方面，車流量檢測(cè)系統(tǒng)的信號(hào)處理算法部分的設(shè)計(jì)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(gè)算法分割為若干模塊，針對(duì)這些不同模塊提出了各種算法改進(jìn)方案。首先提出了提高信號(hào)采集模塊性能的若干算法改進(jìn)，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(cè)法，以便在系統(tǒng)零信號(hào)出現(xiàn)時(shí)，最大程度保證系統(tǒng)檢測(cè)概率的準(zhǔn)確度。最后闡述了一種能有效提高雷達(dá)測(cè)量精度的背景功率譜識(shí)別方法，提出并實(shí)現(xiàn)了該算法在DSP中運(yùn)行的方案，詳細(xì)論述它是如何有效的提高了系統(tǒng)的檢測(cè)精度。此方法已經(jīng)在車流量檢測(cè)雷達(dá)中得到了應(yīng)用，實(shí)驗(yàn)效果明顯。

在大量的實(shí)地外場(chǎng)實(shí)驗(yàn)和各種可靠性測(cè)試后得到了很多有效的實(shí)驗(yàn)數(shù)據(jù)。實(shí)驗(yàn)結(jié)果較好的證明了該系統(tǒng)的可行性和優(yōu)良性，同時(shí)通過對(duì)數(shù)據(jù)的分析和評(píng)測(cè)，也發(fā)現(xiàn)了系統(tǒng)的一些問題，綜合實(shí)驗(yàn)數(shù)據(jù)和測(cè)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(gè)改進(jìn)方案，使用不需要CPU干涉的DMA方式產(chǎn)生雷達(dá)調(diào)治信號(hào)以及利用不同的實(shí)時(shí)時(shí)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(jìn)行了性能上的對(duì)比以及相應(yīng)的驅(qū)動(dòng)更改方案，針對(duì)在新芯片的各項(xiàng)功能在重構(gòu)該系統(tǒng)提出了驅(qū)動(dòng)設(shè)計(jì)的主體框架結(jié)構(gòu)。

關(guān)鍵字：車流量檢測(cè)雷達(dá)，數(shù)字雷達(dá)技術(shù)，多次判定檢測(cè)法，背景功率譜識(shí)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(cè)系統(tǒng)的研究現(xiàn)狀和性能比較 1

1.2.1 車流量檢測(cè)器的常用類型 2

1.2.2 微波車流量檢測(cè)器的優(yōu)良特性 3

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

1.4 本文主要內(nèi)容簡(jiǎn)介 4

第2章 車流量檢測(cè)雷達(dá)系統(tǒng)總體設(shè)計(jì) 6

2.1 車流量檢測(cè)雷達(dá)的基本工作原理 6

2.1.1 車流量檢測(cè)雷達(dá)工作頻段及體制 6

2.1.2 車流量檢測(cè)雷達(dá)工作原理 7

2.1.3 車流量檢測(cè)雷達(dá)的功能 8

2.2 基于DSP的車流量檢測(cè)雷達(dá)系統(tǒng)設(shè)計(jì)方案 9

2.2.1 系統(tǒng)硬件設(shè)計(jì)方案 9

2.2.2 系統(tǒng)軟件設(shè)計(jì)方案 11

2.3 本章小結(jié) 12

第3章 車流量檢測(cè)雷達(dá)數(shù)字信號(hào)處理系統(tǒng)的電路功能實(shí)現(xiàn) 14

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

3.1.1 DSP核心處理器介紹及設(shè)計(jì) 14

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

3.2 采樣模塊設(shè)計(jì) 17

3.2.1 采樣電路設(shè)計(jì) 17

3.2.2 采樣驅(qū)動(dòng)軟件設(shè)計(jì) 18

3.3 雷達(dá)調(diào)制信號(hào)產(chǎn)生模塊的設(shè)計(jì) 21

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

3.3.2 調(diào)頻三角波驅(qū)動(dòng)軟件設(shè)計(jì) 22

3.4 通信模塊設(shè)計(jì) 26

3.4.1 雙通道串口電路設(shè)計(jì) 26

3.4.2 雙通道串口通信驅(qū)動(dòng)軟件設(shè)計(jì) 30

3.5 外擴(kuò)存儲(chǔ)模塊設(shè)計(jì) 33

3.5.1 程序存儲(chǔ)模塊 33

3.5.2 數(shù)據(jù)存儲(chǔ)模塊 36

3.6 本章小結(jié) 37

第4章 車流量檢測(cè)雷達(dá)數(shù)字信號(hào)處理系統(tǒng)算法改進(jìn)與實(shí)現(xiàn) 38

4.1 車流量檢測(cè)算法中的目標(biāo)信息提取和分析方法 39

4.2 提高信號(hào)采集模塊性能的若干算法改進(jìn) 41

4.3 提高目標(biāo)判定模塊性能的多次判定檢測(cè)法 47

4.4 提高車流量檢測(cè)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(cè)雷達(dá)外場(chǎng)實(shí)驗(yàn)測(cè)試結(jié)果及系統(tǒng)改進(jìn)方案 54

5.1 外場(chǎng)實(shí)驗(yàn)測(cè)試結(jié)果 54

5.2 系統(tǒng)改進(jìn)方案 58

5.2.1 系統(tǒng)功能優(yōu)化及擴(kuò)展 58

5.2.2 基于TMS320VC5502的系統(tǒng)改進(jìn)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(xiàn) 69