Created
January 28, 2020 20:26
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Load and plot Galileo satellite phase centres from an Antex file
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| import numpy as np | |
| from matplotlib import pyplot as plt | |
| import time | |
| antexfilename='C:\\Users\\tabbott\\Desktop\\antex\\ngs14.atx' | |
| def readuntil(atx,tofind): | |
| comment='' | |
| while comment!=tofind: | |
| try: | |
| lin=atx.readline() | |
| if len(lin)==0: | |
| print 'end of file ' | |
| break | |
| except: | |
| print 'other error ',traceback.print_exc() | |
| time.sleep(2) | |
| exit(0) | |
| comment=lin[60:-1].strip() | |
| return comment,lin[:60] | |
| atx=open(antexfilename,'r') | |
| print 'opened file',atx.name | |
| numstore=[] | |
| neustore=np.empty((0,3)) | |
| maxplots=5 | |
| galcount=0 | |
| lin=' ' | |
| while (len(lin)>0): | |
| comment,lin=readuntil(atx,'START OF ANTENNA') | |
| if len(lin)>0: | |
| comment,lin=readuntil(atx,'TYPE / SERIAL NO') | |
| antname=lin[:20].strip() | |
| antnum=lin[20:40].strip() | |
| antnumlong=lin[20:60].strip() | |
| if antname[:7]=='GALILEO': | |
| galcount+=1 | |
| comment,lin=readuntil(atx,'DAZI') | |
| dazi=float(lin[:20].strip()) | |
| comment,lin=readuntil(atx,'ZEN1 / ZEN2 / DZEN') | |
| zen=np.fromstring(lin[:60],sep=' ') | |
| comment,lin=readuntil(atx,'# OF FREQUENCIES') | |
| nfreqs=int(lin[:20]) | |
| print 'Line ',atx.tell(),antname,antnumlong | |
| if galcount<maxplots: | |
| fig,ax=plt.subplots(figsize=(8,6)) | |
| for f in range(nfreqs): | |
| comment,lin=readuntil(atx,'START OF FREQUENCY') | |
| freqname=lin[3:20].strip() | |
| comment,lin=readuntil(atx,'NORTH / EAST / UP') | |
| neu=np.fromstring(lin[:60],sep=' ') | |
| if True: #freqname=='E01': | |
| print ' freq',freqname,'has NEU',neu | |
| numstore.append(antnum) | |
| neustore = np.vstack((neustore,neu)) | |
| if galcount<maxplots: | |
| lin=atx.readline() | |
| if lin[3:8]=='NOAZI': | |
| noazi=np.fromstring(lin[8:],sep=' ') | |
| theta=np.linspace(zen[0],zen[1],num=int((zen[1]-zen[0])/zen[2])+1) | |
| ax.plot(theta,noazi,label=freqname) | |
| if galcount<maxplots: | |
| ax.legend(loc=3) | |
| plt.xlabel('nadir angle, degrees (12.5 deg is the limb of the earth') | |
| plt.ylabel('phase centre delta, mm') | |
| plt.xlim([0,12.5]); plt.ylim([-2,1]) | |
| plt.title('%s - %s.\nPhase centre from CoM is N %.1f E %.1f U %.1f mm\n Deviation from phase centre, by frequency is as follows:' | |
| % (antname,antnum,neu[0],neu[1],neu[2])) | |
| ax.grid() | |
| plt.show() | |
| comment,lin=readuntil(atx,'END OF ANTENNA') | |
| atx.close() |
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