北斗二代接收机中的跟踪程序

clc; clear all; close all; format long g; settings = setting_canshu();%设置环路运行参数 loop_para = loop_canshu_calculate(settings);%计算环路滤波器参数 code_table=GOLD_code(); %调用函数，产生伪随机码 fll_nco_adder = 0; carrier_nco_sum = 0; pll_nco_adder = 0; loop_count = 0; code_nco_sum = 0; code_nco_adder = 0; n_IQ = 2; n = 3; output_fll(2:3) = 0; output_filter_fll(1:3) = 0; output_filter_pll(1:3) = 0; output_pll(2:3) = 0; output_filter_ddll(1:3) = 0; pll_after_filter = 0; Tcoh = settings.Tcoh; global modulate_code_nco; %信号源扩频码初相位 modulate_code_nco = settings.modulate_code_bias_phsae; global early_code_nco; % early_code_nco = setting.e_code_original_phase; local_early_code_last = local_earlycode_initial(settings,code_table);%产生本地超前码 for loop_num = 1 : 1500 signal_original = source_(settings); %产生信号源，加噪声，未调制 settings.dot_length = settings.dot_length + 10000;%产生相位连续的信号； flag(loop_num) = settings.PLL_flag; fd_plot(loop_num) = settings.dup_freq; [signal_modulate_code,settings.signal_phase] = signalcode(settings,code_table); %信号源的CB1码 receive_signal = signal_modulate_code.* signal_original; %扩频后的信号 % receive_signal = original_signal; %扩频后的信号 %产生本地再生载波 for demond_num = 1:settings.Ncoh local_cos(demond_num) = cos(2*pi*carrier_nco_sum/2^settings.nco_Length); local_sin(demond_num) = -sin(2*pi*carrier_nco_sum/2^settings.nco_Length); carrier_nco_sum = carrier_nco_sum + settings.middle_freq_nco + fll_nco_adder + pll_nco_adder ;%本地再生载波NCO % carrier_nco_sum = mod(carrier_nco_sum,2^setting.nco_Length); end, code_nco_sum = code_nco_adder + settings.code_word + fll_nco_adder*settings.cofe_FLL_auxi_DDLL; %本地再生码环NCO %code_nco_sum = code_nco_adder + settings.code_word + fll_nco_adder*(1/763); %本地再生码环NCO %产生本地超前，即时，滞后码 [local_early_code,local_prompt_code,local_late_code,settings.local_phase]=localcode_generate(local_early_code_last,code_nco_sum,code_table,settings); local_early_code_last = local_early_code; %载波解调 I_demon_carrier = local_cos.*receive_signal; Q_demon_carrier = local_sin.*receive_signal; % save_I_demon_carrier = [save_I_demon_carrier I_demon_carrier]; % save_Q_demon_carrier = [save_Q_demon_carrier Q_demon_carrier]; %信号解扩并积分清除 I_E_final = sum(I_demon_carrier.*local_early_code); Q_E_final = sum(Q_demon_carrier.*local_early_code); I_P_final(n_IQ) = sum(I_demon_carrier.*local_prompt_code); Q_P_final(n_IQ) = sum(Q_demon_carrier.*local_prompt_code); I_L_final = sum(I_demon_carrier.*local_late_code); Q_L_final = sum(Q_demon_carrier.*local_late_code); % I_P_final(n_IQ) = sum(I_demon_carrier); % Q_P_final(n_IQ) = sum(Q_demon_carrier); if 1 == loop_num I_P_final(n_IQ - 1) = I_P_final(n_IQ); Q_P_final(n_IQ - 1) = Q_P_final(n_IQ); else % % 四象限反正切鉴频器 dot_fll = I_P_final(n_IQ - 1) * I_P_final(n_IQ) + Q_P_final(n_IQ - 1) * Q_P_final(n_IQ); cross_fll = I_P_final(n_IQ - 1) * Q_P_final(n_IQ) - I_P_final(n_IQ) * Q_P_final(n_IQ - 1); output_fll(n) = atan2(cross_fll,dot_fll)/(Tcoh*2*pi); result_discriminator_Fll(loop_num) = output_fll(n); output_filter_fll(n) = (loop_para.cofeone_FLL * output_fll(n)) + (loop_para.cofetwo_FLL * output_fll(n - 1)) + (2 * output_filter_fll(n - 1)) - output_filter_fll(n - 2); fll_after_filter(loop_num) = output_filter_fll(n); fll_nco_adder = output_filter_fll(n) * settings.transfer_coef ; %频率字转换 output_fll(n - 1)=output_fll(n); output_filter_fll(n - 2)=output_filter_fll(n - 1); output_filter_fll(n - 1)=output_filter_fll(n); if settings.PLL_flag == 1 %锁相环鉴相器 output_pll(n) = atan2(Q_P_final(n_IQ),I_P_final(n_IQ)); output_filter_pll(n) = loop_para.cofeone_PLL*output_pll(n) + loop_para.cofetwo_PLL*output_pll(n-1)+loop_para.cofethree_PLL*output_pll(n-2)+2*output_filter_pll(n-1)-output_filter_pll(n-2); result_discriminator_Pll(loop_num) = output_pll(n); pll_after_filter(loop_num) = output_filter_pll(n); pll_nco_adder = (output_filter_pll(n)/(2*pi)) * settings.transfer_coef; %频率字转换 % output_pll(1:2) = output_pll(2:3); % output_filter_pll(1:2) = output_filter_pll(2:3); output_pll(n-2) = output_pll(n-1); output_pll(n-1) = output_pll(n); output_filter_pll(n-2) = output_filter_pll(n-1); output_filter_pll(n-1) = output_filter_pll(n); end I_P_final(n_IQ - 1) = I_P_final(n_IQ); Q_P_final(n_IQ - 1) = Q_P_final(n_IQ); if 0 == settings.PLL_flag && abs(output_fll(n))<10 %锁频环工作状态下，信号与本地频差小于10时 loop_count = loop_count + 1; if loop_count>200 settings.PLL_flag = 1; end elseif 1 == settings.PLL_flag && abs(output_fll(n))>30 %在锁相环工作状态下，锁频环所鉴出的信号与本地频差大于30时 loop_count = loop_count-1; if 0 == loop_count settings.PLL_flag = 0; end end end, %码环鉴别器 output_ddll(n) = ((I_E_final - I_L_final)*I_P_final(n_IQ) + (Q_E_final - Q_L_final)*Q_P_final(n_IQ) )/((I_P_final(n_IQ)^2 + Q_P_final(n_IQ)^2)*2); % DDLL_discri_1 result_ddll(loop_num) = output_ddll(n); %码环滤波器（二阶） output_filter_ddll(n) = output_filter_ddll(n -1) + (loop_para.cofeone_DDLL*output_ddll(n)) + loop_para.cofetwo_DDLL*output_ddll(n - 1); result_DDLL_filter(loop_num) = output_filter_ddll(n); % 转换成频率控制字 code_nco_adder = output_filter_ddll(n) * settings.transfer_coef ; %频率字转换 % Code_NCO=0; % C(loop_num)=code_nco_adder; %替换 output_ddll(n - 1)=output_ddll(n); output_filter_ddll(n - 1) = output_filter_ddll(n); code_phase_discrim(loop_num) = settings.signal_phase - settings.local_phase ; end figure ; subplot(2,1,1); plot(flag); title('FLL+PLL工作 信噪比为-20dB 多普勒频率为80hz'); legend('PLL 工作标志'); xlabel('循环次数') subplot(2,1,2); plot(fll_after_filter + (pll_after_filter/(2*pi)),'b'); hold on; plot(fd_plot,'r'); legend('载波环路滤波器输出值','多普勒频率的真实值'); xlabel('循环次数') figure ; subplot(2,1,1); plot(result_ddll); title('FLL+PLL工作 信噪比为-20dB 多普勒频率为80hz'); legend('DDLL 鉴别结果'); xlabel('循环次数') subplot(2,1,2); plot(result_DDLL_filter,'b'); hold on; % plot(fd_plot,'r'); % legend('DDLL环路滤波器输出值','多普勒频率的真实值'); legend('DDLL环路滤波器输出值'); xlabel('循环次数') % figure ; % subplot(2,1,1); % plot(result_discriminator_Fll); % title('单FLL工作 信噪比为-2dB 多普勒频率为80hz'); % legend('PLL 鉴别结果'); % xlabel('循环次数') % subplot(2,1,2); % plot(fll_after_filter,'b'); % hold on; % plot(fd_plot,'r'); % legend('FLL环路滤波器输出值','多普勒频率的真实值'); % xlabel('循环次数') % figure ; % subplot(2,1,1); % plot(result_discriminator_Pll); % title('单PLL工作 信噪比为-2dB 多普勒频率为80hz'); % legend('PLL 鉴别结果'); % xlabel('循环次数') % subplot(2,1,2); % plot((pll_after_filter/(2*pi)),'b'); % hold on; % plot(fd_plot,'r'); % legend('PLL环路滤波器输出值','多普勒频率的真实值'); % xlabel('循环次数') % figure ; % subplot(2,2,1); % plot(result_discriminator_Fll); % ylabel('FLL 鉴别结果'); % xlabel('循环次数') % subplot(2,2,2); % plot(fll_after_filter + (pll_after_filter/(2*pi))); % ylabel('载波环 滤波结果'); % xlabel('循环次数') % subplot(2,2,3); % plot( flag); % ylabel('PLL启动模式'); % xlabel('循环次数') % subplot(2,2,4); %