1 / 18

SPACE REFLECTO 2013

SPACE REFLECTO 2013. Reflectometry applications with the SX-NSR software receiver Jürgen Dampf, Nico Falk, Thomas Pany, Bernhard Riedl , Jón Winkel IFEN GmbH Place: Telecom Bretagne – Brest campus Date: Nov. 5th, 2013. Overview. What we need for a Reflectometry System Examples

trey
Download Presentation

SPACE REFLECTO 2013

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. SPACE REFLECTO 2013 Reflectometry applications with theSX-NSR software receiver Jürgen Dampf, Nico Falk, Thomas Pany, Bernhard Riedl, Jón Winkel IFEN GmbH Place: Telecom Bretagne – Brest campus Date: Nov. 5th, 2013

  2. Overview • What we need for a Reflectometry System • Examples • Altimetry • Indoor Channel sounding • How to use the SX-NSR for Reflectometry

  3. Reflectometry • Current research done mostly with GPS C/A and eventually L2C • Modernized GPS/Galileo signal to add higher bandwidth signals • More resolution in code phase • Better modeling input, better altimetry • GLONASS and BeiDou to improve availability of suitable reflected signals • Multi-frequency: improved redundancy and accuracy IFEN SX-NSR-R Software receiver based reflectometry system for all civil GNSS signals and all frequencies • Measurement of reflected GNSS signals with respect to the line-of-sight signal • Correlator values • Code delay, Doppler, phase, power • Direct (geometric) and indirect (model based) analysis • Ground based, airborne, satellite borne Future Solution

  4. General Setup PC running SX-NSR NavPort Front-ends Master antenna Pseudorange, Doppler, phase Pseudorange, Doppler, phase USB Master Tracking channel RF switch Measurement antenna Sync. Code, carrier NCO USB Slave Tracking channel Multi-correlator values

  5. Prerequisites – Frontend Sync • Frontend synchronization • Code: ADC sampling within +/- 14 cm • Remaining difference measured internally by NavPort to +/- 2 cm • Carrier: +/- 180° • Sync. stable during runtime but slightlytemperature dependent (a few millimeter) • Antennas, LNAs, Cable, Mixer introduce code and carrier delays • For experiment: identical antennas and cables have been used • Delays are temperature dependent

  6. Prerequisites – Calibration • Calibration for code and carrier phase • Signal from same source • Upper RHCP antenna • Performed at beginning and end • Done by hand • Can be done automatically • To see system delay behavior • Proofed by analyzing calibration sequences • The estimated height should be zero • Delay model up to 6th order

  7. Signal Tracking • 3 user selectable tracking modes • Conventional tracking • PVT based Vector tracking • Synchronized Master/Slave tracking

  8. Altimetry water wood mixed surfaces • Galileo E5 AltBOC Code-Altimetry • Lake south of Graz • Wave height: 0-1 cm • Antenna height: 441 cm • No calibration • Galileo PRN 11 • Altimetry • Surface state • Soil moisture, salinity • Wind speed/direction • Surface cover (ice, ...) • Carrier Phase Altimetry • Lake south of Graz for both Measurements • Antenna height: 271 cm • Wave height: 0-1 cm • Calibration: 15 – 30 – 5 min

  9. Galileo E5 AltBOC Code-Altimetry Results • Coherently slaved multicorrelator • Provides Doppler/delay maps • Coherent integration time 0.02*2^7=2.56 s • cm-level code noise • Flat surface of the lake • 2nd order polynomial fit to obtain peak position AltBOC Correlation Function

  10. Single Frequency Carrier Phase Results • Galileo E5b pilot of Measurement 1 • Calibration • Calibration: 15 – 30 – 5 min • Estimated / True Height • 272.62 cm / 271,00 cm • Offset: 1.62 cm

  11. Dual Frequency Carrier Phase Results • Galileo E1 and E5b pilot of Measurement 1 • Legend: • Blue: Carrier phase differences • Black: Varied integer ambiguities • Red: Sing. Freq. integer ambiguity • Green: Dual Freq. integer ambiguity • Estimated / True Height • 271,83 cm / 271,00 cm • Offset: 8,3 mm

  12. Water Wave Analysis • Effect of water waves on the carrier phase difference of E5b pilot • True wave height: 3-6 cm • True wave frequency: 1-2 waves/sec • Amplitude of carrier phase difference: 3-4 cm • Estimated wave frequency: 1,5 waves/sec

  13. Indoor Channel Sounding I • Setup • Outdoor antenna (e.g. Rooftop) • Static indoor antenna • Each antenna connected to one dedicated front-end • Front-ends sync‘ed 2nd floor 1 (Window) GPS PRN27 GPS PRN25 Correlation functions, 5x 1s integration time Observatory Lustbühel, Graz/Austria

  14. Indoor Channel Sounding II 2nd floor 2 GPS PRN2 GPS PRN27 Correlation functions, 5x 20s integration time 1st floor Galileo PRN20 GPS PRN27 Correlation functions, 5x 20s integration time

  15. SX-NSR for Reflectometry I • RF Front-End • 4 RF bands up to 15 MHz simultaneously • GPS L1, L2P, L2C, L5 • Galileo E1, E5a, E5b, E5a+b (AltBOC), E6 • SBAS L1, L5 • GLONASS G1, G2 • Beidou B1, B2, B3 • User specific ≤ 2.5 GHz • Frontend coupling for 8 RF bands • Dual antenna operation • 1 x high-speed USB2.0 • Interfaces to IMU, PPS, clock, baro., … • 20.48 or 40.96 MHz sample rate • 2-bit, 4-bit or 8-bit sampling • Signal Processing Software • Ultra high sensitivity19 dBHz acquisition10 dBHz tracking • ~20-30 channels per CPU core (real-time) • GNSS baseband processing (acquisition and tracking) for all civil GNSS signals plus GPS L2P • Sensor data synchronization and processing • Position computation with RAIM • Standard interfaces(RINEX, NMEA, SP3(c), …) • Scientific ASCII log files output • C API • Windows PC, 2GB RAM, SSSE3 capable processor

  16. SX-NSR for Reflectometry II • IF samples recording • Prototyping

  17. SX-NSR for Reflectometry III init NSR DLL process close • Integration into SX-NSR using it‘s APIs • Starting pointMatlab prototype code • TaskTranslate to native SX-NSRcode usingBaseband and Navigation API • GoalFully operational, real-time capable Reflectometry System

  18. Conclusion • SX-NSR is the right tool for prototyping Reflectometry systems • Sync‘ed front-ends • Use all civil GNSS signals • Freely definable Multicorrelators • Use our Matlab Toolbox • It is also the right tool for operational use • API for user implementations • Real-time capability • Data recorder for true repeatability • Test different algorithms • Change settings • Run the same IF samples again • Possible applications • Remote Sensing (Altimetry, surface state, ...) • Indoor Channel-Sounding • Bistatic Synthetic Aperture Radar (=passive Radar based on GNSS illumination) • More information and contact: www.ifen.com

More Related