遥测遥控实验报告4

遥测遥控技术实验四学院电子工程学生姓名：严丰班级学号：2902107014 指导老师：李晋一、实验名称：GPS信号跟踪原理与仿真二、实验程序：主程序：function[diata_dll,diata_fll]=tracksignal(iniphcode,inifd,iniph,snr,Code_Method_flag,Carrier_Meth od_flag,codew,codeb,carrierw,carrierfllb,carrierpllb)svnum = 10; %卫星号iniphcode = 500; %生成信号源的码相位inifd = 3000; %生成信号源的载波多普勒频率iniph = 5; %生成信号源的载波初相位snr = 0; %生成信号源的信噪比global time_unit; % 数据跳变时间单位global time; % 数据发送时间global time_cyc;% 一个完整扩频码周期global fs; % 采样率global nn; % 一个完整扩频周期采样点数global kk; % 数据总采样点global F_if; % 载波中频global CA_freq; % PN码速率global tc;global CA ; % 扩频码基玛global F_Carrier; % L1波段载波频率%%%%%%%%%%%%%%%%%%%%%%%%参数设置%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%time = 100*(10^(-3));time_unit = 20*(10^(-3));time_cyc = 1*(10^(-3));fs = 5*(10^6);nn = time_cyc*fs;kk = (time/time_cyc)*nn;F_if = 1.25*(10^6);F_Carrier = 1575.42*(10^6);CA_freq = 1.023*(10^6);%%%%%%%%%%%生成C/A以供使用%%%%%%%%%%PN = codegen(svnum);CA = [];k = 5;for n = 1:length(PN)CA((1+k*(n-1)):k*n) = PN(n)*ones(1,k);endtc = 1/(k*CA_freq);loop_time = time/time_cyc; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%生成信号源 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%Signal_Source是生成的信号源, buffer_bit_data是随机生成的数据位，用于与最后解调的数据进行比对[Signal_Source,Phase_signal,buffer_bit_data]=CreateSource(iniphcode,inifd,iniph,snr); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%捕获%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%[fd_ac,f_ac_code] = acqu(Signal_Source); %%%%%%%%%%%%%%%%%%%%%%%%%%%%定义跟踪中用到的参数%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%IPSum_old = 0.01;QPSum_old = 0.01;%%%%%%%%%%码跟踪环滤波器参数设置%%%%%%%%%%%%%%Code_Method_flag=2; %码跟踪环鉴相法选择标志diffoffside = 0.5; %码鉴相时，正负偏移半个码片k0 =10^(-6); %码跟踪环鉴相器增益k1=10^(-3); %码跟踪环NCO增益%k1 = 50/k0; %码跟踪环NCO增益codew = 20 %自然圆频率codeb = 2 %阻尼系数offside = f_ac_code;theta_code_old = 0;offside_old = f_ac_code;CodeErr_old = 0;Bk_DLL = [];Track_Code_Buffer =[];%%%%%%%%%%%载波跟踪环滤波器参数设置%%%%%%%%%%Last_Phase = 0;Control_Buffer = [];ts = 1/fs; %采样时间间隔Carrier_Method_flag =3; %fll,pll,fll->pll的方法选择标志dem_flag = 0; %fll->pll的切换标志add = 0; %fll->pll的切换过程中用到的变量carrierw = 20 %自然圆频率carrierfllb = 0.707 %阻尼系数carrierpllb = 0.706Track_Freq_Buffer = [];track_dopplar_old = 0;%FLL环参数FLLinput_old=0;FLLoutput_old=0;track_freq_fll = 0;Sita_fll = 0;Bk_FLL = [];%PLL环参数PLLinput_old=0;PLLoutput_old=0;track_freq_pll = 0;Sita_pll = 0;Bk_PLL = [];Buffer_Data =[];adj_buffer = [];ALL_Buffer_Data = [];count_buffer = [];Demodulate_I = [];Local_Ph_Buffer = []; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%跟踪循环%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%for i = 1:1:loop_time% =================part signal source========= %Signal = Signal_Source((i-1)*nn+1:i*nn);% Signalph= Phase_signal((i-1)*nn+1:i*nn);%==============Local carrier===================%t = [0:nn-1]*ts;track_dopplar = fd_ac+track_freq_fll+track_freq_pll;Track_Freq_Buffer = [Track_Freq_Buffer track_dopplar];Local_I = cos(2*pi*(F_if+track_dopplar)*t + Last_Phase);Local_Q = sin(2*pi*(F_if+track_dopplar)*t + Last_Phase);Iph = 2*pi*(F_if+track_dopplar)*t + Last_Phase;Local_Ph_Buffer = [Local_Ph_Buffer Iph];Last_Phase = Last_Phase + 2*pi*(F_if+track_dopplar)*time_cyc; %%上一次积分结束点的相位Carrier_I = Local_I;Carrier_Q = Local_Q;% =================Create Localcode============== %ph_code_p = offside;fd_code_p = track_dopplar;CA_Code_p = CAcode(ph_code_p,fd_code_p,i);lc_p = CA_Code_p.*Signal;ph_code_e = offside+diffoffside;fd_code_e = track_dopplar;CA_Code_e = CAcode(ph_code_e,fd_code_e,i);lc_e = CA_Code_e.*Signal;ph_code_l = offside-diffoffside;fd_code_l = track_dopplar;CA_Code_l = CAcode(ph_code_l,fd_code_l,i);lc_l = CA_Code_l.*Signal;% ==========================multiply================================ %Local_P_I = lc_p.*Carrier_I;Local_P_Q = lc_p.*Carrier_Q;Local_E_I = lc_e.*Carrier_I;Local_E_Q = lc_e.*Carrier_Q;Local_L_I = lc_l.*Carrier_I;Local_L_Q = lc_l.*Carrier_Q;% ========================integration============================= %IPSum = sum(Local_P_I);QPSum = sum(Local_P_Q);IESum = sum(Local_E_I);QESum = sum(Local_E_Q);ILSum = sum(Local_L_I);QLSum = sum(Local_L_Q);% =======================Code Control==================================if Code_Method_flag==1%鉴想器theta_code = k0*((IESum.^2+QESum.^2)-(ILSum.^2+QLSum.^2));%码环路滤波器[CodeErr] = CodeLoopFilter(codew,codeb,theta_code,theta_code_old,CodeErr_old); %CodeErr是经过滤波器输出的码相位误差的估计值%码环NCOoffside=offside_old+60*k1*CodeErr; %码NCO的输出theta_code_old = theta_code; %将当前结果保存，用于下一个循环的码跟踪CodeErr_old = CodeErr; %将当前结果保存，用于下一个循环的码跟踪offside_old = offside; %将当前结果保存，用于下一个循环的码跟踪Bk_DLL = [Bk_DLL theta_code]; %记录跟踪过程中的码环鉴想器的输出Track_Code_Buffer = [Track_Code_Buffer offside]; %记录跟踪过程中的码环NCO的数出elseif Code_Method_flag==2%鉴想器theta_code = ((IESum.^2+QESum.^2)-(ILSum.^2+QLSum.^2))/((IESum.^2+QESum.^2)+(ILSum.^2+QLSum.^2));theta_code =10.^(-3)*(1-sqrt(1-theta_code.^2))/(2*theta_code);%码环路滤波器[CodeErr] = CodeLoopFilter(codew,codeb,theta_code,theta_code_old,CodeErr_old); %CodeErr是经过滤波器输出的码相位误差的估计值%码环NCOoffside=offside_old+500*CodeErr; %码NCO的输出theta_code_old = theta_code; %将当前结果保存，用于下一个循环的码跟踪CodeErr_old = CodeErr; %将当前结果保存，用于下一个循环的码跟踪offside_old = offside; %将当前结果保存，用于下一个循环的码跟踪Bk_DLL = [Bk_DLL theta_code]; %记录跟踪过程中的码环鉴想器的输出Track_Code_Buffer = [Track_Code_Buffer offside]; %记录跟踪过程中的码环NCO的数出end% ====================Carrier control=============================%if Carrier_Method_flag == 1 %%%%%%%%%%%%%%% fll跟踪环路%鉴想器real_Q = IPSum_old*QPSum-QPSum_old*IPSum;real_I = IPSum_old*IPSum+QPSum_old*QPSum;a=real_Q/real_I;theta_fll = atan(real_Q/real_I);Bk_FLL = [Bk_FLL theta_fll];FLLinput = theta_fll/(2*pi*time_cyc);%环路滤波器FLLoutput = CarrierLoopFilter(carrierw,carrierfllb/2,FLLinput,FLLinput_old,FLLoutput_old);%FLL环NCOSita_fll = Sita_fll+FLLoutput;track_freq_fll = -Sita_fll; %FLL环跟踪到的多普勒频率 (由于反正切主值区间造成的)FLLinput_old=FLLinput; %将当前结果保存，用于下一个循环的载波跟踪FLLoutput_old=FLLoutput; %将当前结果保存，用于下一个循环的载波跟踪IPSum_old = IPSum; %将当前结果保存，用于下一个循环的载波跟踪QPSum_old = QPSum; %将当前结果保存，用于下一个循环的载波跟踪elseif Carrier_Method_flag == 2 %%%%%%%%%%%%%%%%%%%%%%%costa跟踪环路theta_pll = atan(QPSum/IPSum);PLLinput = theta_pll/(2*pi*time_cyc);Bk_PLL = [Bk_PLL theta_pll];%LoopFilterPLLoutput = CarrierLoopFilter(carrierw,carrierpllb/2,PLLinput,PLLinput_old,PLLoutput_old);track_freq_pll = -PLLoutput;PLLinput_old=PLLinput; %将当前结果保存，用于下一个循环的载波跟踪PLLoutput_old=PLLoutput; %将当前结果保存，用于下一个循环的载波跟踪elseif Carrier_Method_flag == 3 %%%%%%%%%%%%%%%%%%%%fll跟踪环路->costaif dem_flag == 0real_Q = IPSum_old*QPSum-QPSum_old*IPSum;real_I = IPSum_old*IPSum+QPSum_old*QPSum;theta_fll = atan(real_Q/real_I);FLLinput = theta_fll/(2*pi*time_cyc);Bk_FLL = [Bk_FLL theta_fll];%LoopFilterFLLoutput = CarrierLoopFilter(carrierw,carrierfllb/2,FLLinput,FLLinput_old,FLLoutput_old);;%NCOSita_fll = Sita_fll+FLLoutput;track_freq_fll = -Sita_fll;FLLinput_old=FLLinput; %将当前结果保存，用于下一个循环的载波跟踪FLLoutput_old=FLLoutput; %将当前结果保存，用于下一个循环的载波跟踪IPSum_old = IPSum; %将当前结果保存，用于下一个循环的载波跟踪QPSum_old = QPSum; %将当前结果保存，用于下一个循环的载波跟踪elseif dem_flag == 1theta_pll = atan(QPSum/IPSum);PLLinput = theta_pll/(2*pi*time_cyc);Bk_PLL = [Bk_PLL theta_pll];%LoopFilterPLLoutput = CarrierLoopFilter(carrierw,carrierpllb/2,PLLinput,PLLinput_old,PLLoutput_old);track_freq_pll = -PLLoutput;PLLinput_old=PLLinput; %将当前结果保存，用于下一个循环的载波跟踪PLLoutput_old=PLLoutput; %将当前结果保存，用于下一个循环的载波跟踪endendadj_flag = track_dopplar - track_dopplar_old; %相邻两次跟踪到的多普勒频率值之差，用以判断是否FLL跟踪的频率已经足够精确,从而转入PLLtrack_dopplar_old = track_dopplar;adj_buffer = [adj_buffer adj_flag];outdata = sign(real(IPSum));ALL_Buffer_Data = [ALL_Buffer_Data outdata];if adj_flag < 1 %看相邻两次跟踪到的多普勒频率之差是否小于1Hzadd = add+1;elseadd = 0;endif add >= 2 %看是否有连续两次跟踪到的多普勒频率之差小于1Hz，若有，则认为频率跟踪已很稳定而精确，可以转入PLLdem_flag = 1;endif dem_flag == 1count_time = i;count_buffer = [count_buffer count_time];Buffer_Data = [Buffer_Data outdata]endend%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%位同步与数据解调%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%Buffer_Data_out = framecheck2(Buffer_Data,count_buffer); %位同步l_i_d = time/time_unit;l_o_d = length(Buffer_Data_out);l_zeros = l_i_d - l_o_d;Buffer_Data_out = [zeros(1,l_zeros) Buffer_Data_out]; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%计算跟踪精度%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%Track_Code_Buffer;Track_Freq_Buffer;l_dll = length(Track_Code_Buffer);l_fll = length(Track_Freq_Buffer);diata_dll = sqrt(sum((Track_Code_Buffer(40:l_dll)-iniphcode).^2)/length(Track_Code_Buffer(40:l_dll))); %码跟踪环跟踪精度diata_fll = sqrt(sum((Track_Freq_Buffer(40:l_fll)-inifd).^2)/length(Track_Freq_Buffer(40:l_fll)));%载波跟踪环的跟踪精度%Track_Ph_Buffer = Local_Ph_Buffer-Phase_signal; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%画图显示跟踪结果%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%subplot(1,2,1);plot(Track_Code_Buffer);xlabel('时间(ms)');ylabel('码相位跟踪值');title('码跟踪结果');grid onsubplot(1,2,2);plot(Track_Freq_Buffer);xlabel('时间(ms)');ylabel('多普勒频率跟踪结果(Hz)')title('载波跟踪结果');grid on% figure;%plot([1:length(buffer_bit_data)],buffer_bit_data,'b*',[1:length(Buffer_Data_out)],Buffer_Dat a_out,'ro');% set(gca,'xtick',[1:1:5]);% set(gca,'xticklabel',{'1','2','3','4','5'});% set(gca,'ytick',[-1:1:1]);% set(gca,'yticklabel',{'-1','0','1'});% xlabel('数据位');% ylabel('解调结果')% title('数据解调输出结果');% legend('数据','解调输出数据');% grid on% figure;% plot(Bk_DLL);% title('Track Code 输入控制')% grid on%% figure;% plot(Track_Ph_Buffer);% title('Track differ Phase')% grid on三、实验结果：数据修改：svnum = 10; %卫星号iniphcode = 300; %生成信号源的码相位inifd = 4000; %生成信号源的载波多普勒频率iniph = 5; %生成信号源的载波初相位snr = 0; %生成信号源的信噪比实验运行结果：a.输出结果截图：b.程序输出结果：ans =21.5481c.码相位跟踪结果及载波跟踪结果matlab波形图:。