nvs.asv

根据卫星星历及测者位置

% number of visible satellites
t=0:300:(24*60*60); %　每30秒更新一次数据，记录24小时内数据
nvs_gps = 6 + 2 * rand(size(t));
nvs_gal = 7 + 2 * rand(size(t));
plot(t,nvs_gps,'r-')
axis([0,5,0,2])
hold on
plot(t,nvs_gal,'b-')
xlabel('t');    ylabel('n');
hold off