1 / 73

PRESENT SATELLITE RADIO NAVIGATION SYSTEMS, THEIR PERFORMANCE AND USER RECEIVER CONCEPTS

PRESENT SATELLITE RADIO NAVIGATION SYSTEMS, THEIR PERFORMANCE AND USER RECEIVER CONCEPTS. František Vejražka , Pavel Kovář, Libor Seidl, Petr Kačmařík, Josef Špaček, Pavel Puričer Department of Radio Engineering Czech Technical University in Prague Czech Republic. Abstract.

synnove-sven
Download Presentation

PRESENT SATELLITE RADIO NAVIGATION SYSTEMS, THEIR PERFORMANCE AND USER RECEIVER CONCEPTS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. PRESENT SATELLITE RADIO NAVIGATION SYSTEMS,THEIR PERFORMANCEANDUSER RECEIVER CONCEPTS František Vejražka, Pavel Kovář, Libor Seidl, Petr Kačmařík, Josef Špaček, Pavel Puričer Department of Radio Engineering Czech Technical University in Prague Czech Republic

  2. Abstract This contribution gives an overview of present and future navigation systems and their augmentations such as GPS, GLONASS, GALILEO, WAAS, EGNOS, MSAT, QZSS, BEIDOU, GAGAN. Performance of the systems depends on their technical parameters. We will try to evaluate these and to present our opinion on their advantages for different applications and in various situations (reception of weak signals suffering from great attenuation under vegetation canopy, in urban canyons, influence of reflections and multipath). The last part of the contribution deals with an application of software radio technology for user receiver design and results obtained from experiments with different algorithms of processing the satellite navigation systems signals.

  3. Terminology Satellite (Radio) Navigation Systems ~ Radio Determination Satellite Systems ~ Systems for radio position determination using satellites

  4. Satellite Navigation Systems Historical Satellite Navigation Systems(not realized) • 601 • TIMATION • ... • GEOSTAR • REXSTAR GPS - NAVSTAR

  5. Satellite Navigation Systems Past Satellite Navigation Systems • NNSS - Transit • Tsikad GPS - NAVSTAR realized but cancelled

  6. Satellite Navigation Systems GLONASS full operational GALILEO GPS - NAVSTAR in the air, not fully operational, lack of reliable satellites projected, in development, operational from 2008

  7. Satellite Navigation Systems Global systems: Augmentation systems: GPS-NAVSTAR GLONASS GALILEO WAAS NDGPS EGNOS MSAS GAGAN QZSS → GALILEO Local systems: BEIDOU …

  8. Principles of Satellite Navigation Systems • Doppler systems • Ranging systems

  9. satellite orbit T t3 t2 satellite t4 r2 r3 t1 fv r1 r4 fp timemarks receiver stop ti+1+Dti+1 start ti+Dti user f0-fp mixer counter f0 fp Ni oscillator fv t4+t4 t1+t1 t3+t3 t2+t2 Principles of Satellite Navigation Systems – Doppler Systems Ni = ΔFΔT+(f0/c){√[(xi+1-x)2+(yi+1-y)2+(zi+1-z)2 ]– √[(xi-x)2+(yi-y)2+(zi-z)2]}i = 1, 2, 3

  10. (x1, y1, z1) (x2, y2, z2) d2 = c2 z (x3, y3, z3) d1 = c1 d3 = c3 (x4, y4, z4) signaltransmittedby satellite (x, y, z) d4 = c4 x y 0 0 i = di /c signalreceived by user mi 0 tuser Principles of Satellite Navigation Systems – Ranging Systems (xi -x)2 + (yi -y)2 + (zi -z)2= (ci)2i = 1, 2, 3 (xi -x)2+ (yi -y)2+ (zi -z)2 = (c (mi-0) )2 i = 1, 2, 3,4

  11. +1 t m -1 R()  -  0  C(t) range code inside receiver +1 received C(t+) code t -1

  12. C(t) R() C*(t) R*()  0 m C*(t) unwanted satelliterange code C*(t)  C(t) GPSDELAY DISCRIMINATOR correlator C(t+) C() generátor delay delay control clock

  13. uL() C(t - R - /2) u() C(t - R + /2) u()= uL() -uE() uE() uL() uE()  -/2 /2 -/2 /2  GPSEARLY-LATE DISCRIMINATOR correlator R + C(t - m) m = R +  C() generator filter - correlator clock

  14. Receiver Principle C(t)D(t)cos(2ft) [C(t)D(t)(1+cos(4ft))] C2(t)D(t) = D(t) C(t)D(t) cos(2ft) ()2 m pseudorange C2(t) = 1D2(t) = 1 delay discriminator phase lock C(t)

  15. Systems Parameters (Properties) We will deal with systems: • GPS – NAVSTAR • GLONASS • GALILEO

  16. GPS - NAVSTAR

  17. D2 E1 B3 C2 B2 F4 D1 A3 F3 F1 A4 D3 E4 B4 C1 A2 B1 F2 A1 C3 E2 E3 C4 D4 GPS Constellation Plane F E D C B A 160° 120° 80° Mean anomaly 40° Equator 0° 320° 280° satellite 240° operational spare 200° 17° 137° 257° 77° 197° 317° Right ascension of ascending node Inclination 55° Semimajor axis 26561.75 km (altitude above Earth 20183,6 km) Excentricity nominally e = 0, generally e < 0,02

  18. P(Y) P(Y) GPS Present Signal Structure (1/3) Signal in time domain: L1: s(t)=ACCC/A(t).D(t)cos(2πf1t)+APP(t).D(t)sin(2πf1t) L2: s(t)=APP(t).D(t)sin(2πf1t) Code multiplex - each satellite has own range codes CC/A(t) and P(t) Signal in frequency domain: L1 1575,42 MHz ±12 MHz L2 1227,6 MHz ±12 MHz C/A ARNS/RNSS RNSS 1215 1260 1559 1610 MHz

  19. Navigation Message (Data) Content: transmitting satellite Kepler parameters almanac – Kepler parameters of others satellites satellite „health“ corrections of satellite clock frequency troposphere refraction … Organisation of DataFrame: 2 3 1 4 5 1 2 3 4 5 6 7 8 9 0 GPS ParametersSignal Structure (2/3) navigation message = 25 pages ~ 12,5 mins frame = 1500 bits ~ 30 s ~ 5 subframes 25 pages subframe=10 words ~ 6 s word = 30 bits ~ 0,6 sbit ~ 20 ms

  20. GPS ParametersSignal Structure (3/3) Navigation Message FEC Hamming Coding

  21. GPS Services • SPS – Standard Positioning Serviceonly C/A code accessible • PPS – Precision Positioning Servicefor authorized usersP(Y) code accessible

  22. GLONASS

  23. GLONASS Constellation • 24 satellites (8 satellites in each of 3 planes) • e ~ 0 (circular orbit) • inclination 64.8° • altitude 19 100 km, • orbit period 11h 15m • angular spacing between orbits 120°

  24. GLONASSSignal Structure • Frequencies: • L1: fj = 1602 + 9j/16 • L2: fi = 1246 + 7i/16 [MHz] • Modulation: • Navigation message • Pseudorandom ranging code • Sequence of maximum length • Period 1 msec • Bit rate 511 kb/s • 100 Hz auxiliary meander sequence – Manchester code

  25. GLONASS Signal Structure • Data • Hamming code (84,8) • 50 b/s in strings • 15 strings ~frame • 5 frames ~navigation message ~2.5 min 85 bits 111110…110 No 0 Data Parity Time mark 1.7 sec 0.3 sec 2 sec

  26. 26 22 16 16 14 13 12 12 12 12 12 11 10 10 9 8 8 7 1992 1993 1994 1995 1996 1997 1998 1999 2000 2004 1987 1988 1989 1990 1991 2001 2002 2003 GLONASS Constellation history

  27. GALILEO

  28. GALILEO Constellation • 3 GEO satellites: • Inmarsat III • AOR-E 15.5°W • F5 25.0°E • ESA Artemis 21.5°E • 30 MEO satellites: • 9 satellites in each of 3 planes (Walker constellation 27/3/1) • 3 spare satellites (1 in each plane) • e = 0 (circular orbits) • inclination 56° • altitude 23 616 km • orbit period 14h 21.6m ~ 1+2/3 rev. a day ~ ground track repeats every 3 days

  29. GALILEO GALILEO LOCAL LOCAL COMPONENTS COMPONENTS CORE SYSTEM CORE SYSTEM MEO CONSTELLATION MEO CONSTELLATION IMS IMS Local Infra- struct. Local Infra- struct. regional uplink regional uplink Network Network IULS IULS …. …. REGIONAL REGIONAL NAV SIS NAV SIS NAV SIS NAV SIS Communication link Communication link COMPONENTS COMPONENTS ICC ICC NAV SIS NAV SIS NAV SIS NAV SIS . . . . . . . . . . . . S-band uplink S-band uplink C-band uplink C-band uplink GSS Network GSS Network IMS IMS Network Network Local Infra- struct. Local Infra- struct. TTC uplink TTC uplink Mission uplink Mission uplink ICC ICC Communication link Communication link INTEGRITY DETERMINATION INTEGRITY DETERMINATION NAVIGATION CONTROL & NAVIGATION CONTROL & IMS IMS & DISSEMINATION & DISSEMINATION CONSTELLATION MANAGEMENT CONSTELLATION MANAGEMENT GCC GCC L-band L-band UHF UHF NAV NAV SAR SAR USER SEGMENT USER SEGMENT External External COSPAS-SARSAT COSPAS-SARSAT Complementary Complementary GROUND SEGMENT GROUND SEGMENT Systems Systems GALILEOArchitecture

  30. GALILEOServices • OS – Open Servicefree of charge, positioning, navigation, timing services • CS – Commercial Serviceadded value to OS, garanteed services • SoL – Safety of Lifeintegrity message • PRS – Public Regulated Servicepolice, customs, ...dedicated signal, under governmental control • SAR – Search and Rescuecoordinated with COSPAS – SARSAT

  31. E5 E6 E2 L1 E1 L6 1559.00 1591.00 1563.00 1587.00 1544.10 1260.00 1300.00 1215.00 1164.00 SAR downlink GALILEOSignals and Spectra ARNS ARNS 960 MHz 1214 MHz 1559 MHz 5250 MHz RNSS RNSS 1300 MHz 1559 MHz 5030 MHz 1151 MHz ≈ ≈ ≈ f [MHz] ARNS – Aeronautical Radio Navigation Service RNSS – Radion Navigation Satellite Service

  32. s(t) = carrier x subcarier x (ranging)code subcarrier – code – PRN GALILEO Signals and Spectra – BOC(m,n) TS TC BOC modulation BOC(m,n)

  33. BOC(1,1) BPSK(1) GALILEOBOC Spectrum m = 1 – subcarrier frequency is 1.023 MHz n = 1 – range code chip frequency is 1.023 MHz

  34. GALILEOBOC Correlation Function BOC(1,1) m = 1 – subcarrier frequency is 1.023 MHz n = 1 – range code chip frequency is 1.023 MHz

  35. GALILEOBOC modulation BOC(1,1) BOC(5,1) BOC(5,2) correlationfunction spectrum

  36. I IN PHASE sin() IN QUADRATURE cos() Q GALILEOSignals, Services and Spectra E2 L1 E1 1559.00 1591.00 1563.00 1587.00 1575.420 SoL uses the same signals as OS with integrity message 1561.098 1589.742

  37. 1215.00 1164.00 I E5 IN PHASE sin() Q IN QUADRATURE cos() GALILEOSignals, Services and Spectra 1191.795 1207.140 1176.450 • Differerent signals are broadcast • on I and Q channels • in upper (E5b) and lower (E5a) part of the band • E5a and E5b may be used asa single ultra wide channel E5b E5a

  38. I 1260.00 1300.00 1268.520 1278.750 1288.980 E6 IN PHASE sin() IN QUADRATURE cos() Q GALILEOSpectrum, Services and Spectra

  39. 1260.00 1300.00 1215.00 1164.00 ≈ ≈ ≈ GALILEOSignal, Services andSpectra E5 E6 E2 L1 E1 L6 1559.00 1591.00 1563.00 1587.00 1544.10 E5a E5b I 1176.450 1191.795 1207.140 1268.520 1278.750 1288.980 1575.420 SAR downlink IN PHASE sin() IN QUADRATURE cos() 1561.098 1589.742 Q

  40. GALILEOService Parameters

  41. BEIDOU

  42. BEIDOU „China‘s „Beidou“ navigation system is a regional positioning system mainly covering the country and its neighbouring areas, thus making vertical positioning impossible and limiting the number of users.“ • 3 geostationary satellites • circular orbits

  43. BEIDOUConstellation (Beidou 1B orbit)

  44. Augmentations

  45. transmiter reference station user reference station AugmentationDifferential GPS (DGPS) knowncoordinates corrections receiver receiver

  46. receiverreferencestation user receiver AugmentationDifferential GPS (DGPS) knowncoordinates corrections transmitter reference station

  47. Augmentations • Many systems • NDGPS • maritime systems • Systems with satellite channel for corrections transmission • WADGPS • SBAS (ICAO) – Satellite Based Augmentation Systems • WAAS • MSAS • EGNOS→ future part of GALILEO • …

  48. AugmentationsSBAS - Constellation MSAS GAGAN EGNOS WAAS MTSAT INMARSAT ARTEMIS INMARSAT GPS

  49. AugmentationsSBAS - signals Similar to SATNAV systems signals

  50. AugmentationQZSS

More Related