【數(shù)字信號】基于matlab模擬GPS信號頻譜
【數(shù)字信號】基于matlab模擬GPS信號頻譜
TT_Matlab
博主簡介：擅長智能優(yōu)化算法、神經(jīng)網(wǎng)絡(luò)預(yù)測、信號處理、元胞自動機(jī)、圖像處理、路徑規(guī)劃、無人機(jī)等多種領(lǐng)域的Matlab仿真，完整matlab代碼或者程序定制加qq1575304183。
?作者簡介：熱愛科研的Matlab仿真開發(fā)者，修心和技術(shù)同步精進(jìn)，matlab項目合作可私信。
個人主頁： Matlab科研工作室
個人信條：格物致知。
更多Matlab仿真內(nèi)容點擊
智能優(yōu)化算法 神經(jīng)網(wǎng)絡(luò)預(yù)測 雷達(dá)通信 無線傳感器 電力系統(tǒng)
信號處理 圖像處理 路徑規(guī)劃 元胞自動機(jī) 無人機(jī)
? 內(nèi)容介紹
全球定位系統(tǒng)（GPS）使用的信號頻譜包括L1、L2和L5三個頻段。L1頻段的中心頻率為1575.42 MHz，L2頻段的中心頻率為1227.60 MHz，L5頻段的中心頻率為1176.45 MHz。
其中，L1頻段是GPS主要信號頻段，它是一種帶有碼偽造的載波信號，可用于計算位置、速度和時間等信息；L2頻段是GPS的輔助信號頻段，可用于計算大氣延遲誤差等信息；L5頻段是GPS的高精度信號頻段，其波長更短，受多徑誤差以及干擾影響較小，可提供更加準(zhǔn)確的定位數(shù)據(jù)。
此外，GPS還包括P碼和C/A碼信號，其中P碼信號使用在L1和L2頻段，提供高精度的定位數(shù)據(jù)；C/A碼信號是低精度信號，主要用于民用衛(wèi)星導(dǎo)航。
? 部分代碼
function CAcode = generateCAcode(PRN)
% generateCAcode.m generates one of the 32 GPS satellite C/A codes.
%
% CAcode = generateCAcode(PRN)
%
% Inputs:
% PRN - PRN number of the sequence.
%
% Outputs:
% CAcode - a vector containing the desired C/A code sequence
% (chips).
%--------------------------------------------------------------------------
% SoftGNSS v3.0
%
% Copyright (C) Darius Plausinaitis
% Written by Darius Plausinaitis
% Based on Dennis M. Akos, Peter Rinder and Nicolaj Bertelsen
%--------------------------------------------------------------------------
%This program is free software; you can redistribute it and/or
%modify it under the terms of the GNU General Public License
%as published by the Free Software Foundation; either version 2
%of the License, or (at your option) any later version.
%
%This program is distributed in the hope that it will be useful,
%but WITHOUT ANY WARRANTY; without even the implied warranty of
%MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
%GNU General Public License for more details.
%
%You should have received a copy of the GNU General Public License
%along with this program; if not, write to the Free Software
%Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
%USA.
%--------------------------------------------------------------------------
%CVS record:
%$Id: generateCAcode.m,v 1.1.2.5 2006/08/14 11:38:22 dpl Exp $
%--- Make the code shift array. The shift depends on the PRN number -------
% The g2s vector holds the appropriate shift of the g2 code to generate
% the C/A code (ex. for SV#19 - use a G2 shift of g2s(19) = 471)
g2s = [ 5, 6, 7, 8, 17, 18, 139, 140, 141, 251, ...
252, 254, 255, 256, 257, 258, 469, 470, 471, 472, ...
473, 474, 509, 512, 513, 514, 515, 516, 859, 860, ...
861, 862 ... end of shifts for GPS satellites
... Shifts for the ground GPS transmitter are not included
... Shifts for EGNOS and WAAS satellites (true_PRN = PRN + 87)
145, 175, 52, 21, 237, 235, 886, 657, ...
634, 762, 355, 1012, 176, 603, 130, 359, 595, 68, ...
386];
%--- Pick right shift for the given PRN number ----------------------------
g2shift = g2s(PRN);
%--- Generate G1 code -----------------------------------------------------
%--- Initialize g1 output to speed up the function ---
g1 = zeros(1, 1023);
%--- Load shift register ---
reg = -1*ones(1, 10);
%--- Generate all G1 signal chips based on the G1 feedback polynomial -----
for i=1:1023
g1(i) = reg(10);
saveBit = reg(3)*reg(10);
reg(2:10) = reg(1:9);
reg(1) = saveBit;
end
%--- Generate G2 code -----------------------------------------------------
%--- Initialize g2 output to speed up the function ---
g2 = zeros(1, 1023);
%--- Load shift register ---
reg = -1*ones(1, 10);
%--- Generate all G2 signal chips based on the G2 feedback polynomial -----
for i=1:1023
g2(i) = reg(10);
saveBit = reg(2)*reg(3)*reg(6)*reg(8)*reg(9)*reg(10);
reg(2:10) = reg(1:9);
reg(1) = saveBit;
end
%--- Shift G2 code --------------------------------------------------------
%The idea: g2 = concatenate[ g2_right_part, g2_left_part ];
g2 = [g2(1023-g2shift+1 : 1023), g2(1 : 1023-g2shift)];
%--- Form single sample C/A code by multiplying G1 and G2 -----------------
CAcode = -(g1 .* g2);
? 運(yùn)行結(jié)果
? 參考文獻(xiàn)
[1]周柱,石峰,張爾揚(yáng),等.一種GPS接收機(jī)級聯(lián)抗干擾方法[J].信號處理, 2010, 26(9):7.DOI:10.3969/j.issn.1003-0530.2010.09.010.