RASS-R Training Radar Comparator Dual RCD 26-Jan-09 Jeroen Janssens Title

Outline Module Objectives RCD part of RASS-R 26-Jan-09 Outline Module Objectives RCD part of RASS-R Radar Comparator Dual – intro Benefits and possibilities Operation Flow Parameter and node setup Data Analyser Filter Displays Statistics Practical use of RCM Module objectives Summary Title

Module objectives State the major difference between the RCM and RCD 26-Jan-09 Module objectives State the major difference between the RCM and RCD State why ADS-B is the preferred data source for the reference node when making a RCD analysis Describe how accuracy information is derived for the “Accuracy Ref” and “Accuracy RUT” displays State the four types of analysis that can be made with the Data Analyser in the RCD State how to apply “Time Stamp” correction to ADS-B reference data Describe the filtering requirements for ADS-B data that is used in the “reference” node of the RCD Title

RCD part of RASS-R Programmed in Labview Part of RASS-R toolbox 26-Jan-09 RCD part of RASS-R Programmed in Labview Part of RASS-R toolbox Title

Radar Comparator Dual Radar analysis software 26-Jan-09 Radar Comparator Dual Radar analysis software Radar manufacturer independent The RCD uses two sources of opportunity data at a time Two modes: mono radar (RCM) ↔ dual radar (RCD) For PSR, (M)SSR, Mode-S, ADS-B data Calculations based on Radar vs Radar or Radar vs ADS-B Performance figures: systematic errors range bias range gain azimuth bias time bias random errors (mono radar based estimates) range azimuth timestamp Title

Benefits and possibilities 26-Jan-09 Benefits and possibilities Efficient software tool for the radar performance analysis (“brains”) Fully transparent radar data processing, versatile cross-referencing display functions throughout the analysis User friendly radar evaluation setup configuration and operation S4 and D6 formats are directly used for the RCD analysis Barometric correction of the target altitude based on the barometric sounding data Refraction correction Encoder correction based on RASS-S gyroscope measurement Timestamp statistics Extended plot, track, trajectory info reporting Versatile universal filter interface used throughout the Radar Comparator tools and utilities Title

26-Jan-09 RCD Operation flow (1) Title

RCD Operation flow (2) Functioning of the algorithm: 26-Jan-09 RCD Operation flow (2) Functioning of the algorithm: Correlate the data originating from two sources (radar or ADS-B) Build a system of equations allowing to resolve a number of parameters (systematic errors) Solve iteratively the system to determine these unknown systematic errors, minimizing the system functional Compensate both data sets for the measured systematic errors Reconstruct the true trajectory given the measurement noise and minimizing speed noise and the random errors of both sources Compare both sources vs. the reconstructed trajectory in order to evaluate the random errors Title

RCD Operation flow (3) Steps to be followed: 26-Jan-09 RCD Operation flow (3) Steps to be followed: Create a campaign folder on the computer Parameter and node setup for REF and RUT Time analysis of the data with data analyser Load barometric sounding file in data analyser Correct setting of filter Processing “trajectory reconstruction” Analysis of the results in the different displays and statistics tables  use always in combination with info window!  crosslink between different windows! Title

Parameter setup Different types of parameters: Parameters-group 26-Jan-09 Parameter setup Different types of parameters: Parameters-group Plot-to-track correlation Type correlation (“S address to position” – for ADS-B REF to SSR RUT) XY correlation window Time correlation Height correlation Trajectory reconstruction ON - combination of reference/radar under test OFF - reference only Remark: any change of a parameter should be confirmed by pressing ENTER! Otherwise when leaving the parameter it will revert to the previous value! Title

Node setup Node-group Fill in as precise as possible! 26-Jan-09 Node setup Node-group Parameters (radar): Latitude, Longitude, Height Data type ADS-B, PSR, SSR, Mode-S Position type Rho::Theta, XY (radar plane), XY (Cartesian), LAT::LON Accuracy parameters Coverage volume: resolution, screening file, range Data paths to S4/D6 files (recorded with RASS-S/R) Corrections barometric sounding file encoder file timestamp refraction Fill in as precise as possible! ADS-B is the preferred data source for the reference node as the positional information contains true MSL height, has a high update rate and uniform positional accuracy. Title

Outline RCD part of RASS-R Radar Comparator Dual – intro 26-Jan-09 Outline RCD part of RASS-R Radar Comparator Dual – intro Benefits and possibilities Operation Flow Parameter and node setup Data Analyser Timestamp analysis Barometric analysis Refraction error Eccentricity error Filter Displays Statistics Practical use of RCM Module objectives Summary Title

26-Jan-09 Data Analyser Measure errors of different nature that can be present in the data and therefore affect the radar performance analysis  Measure timestamp errors  Measure barometric errors Visualization in Graph Statistics table Title

Data Analyser – Timestamp Analysis 26-Jan-09 Data Analyser – Timestamp Analysis Verify timestamp accuracy for correct trajectory reconstruction Check integrity of timestamps for plot/track data, sector and north messages Correction performed= linear fit Different displays of plots before plot-to-track correlation Azimuth vs time Error vs Azimuth Error vs Time Plot density vs Time Gives insight in the unprocessed data Useful when determining revolution time of the radar Filter settings:  Filter out sector messages  Data contains both plot and track data Title

Data Analyser – Barometric Correction Data 26-Jan-09 Data Analyser – Barometric Correction Data C-code from airborne altimeter= air pressure converted to height according “ICAO Standard Atmosphere 1964 model” Different weather conditions= different air pressure  reported C-code deviation from true height Barometric measurements from weather stations all over the world Measurement data = sounding-files Sounding files Retrieved via the internet Stored on disk for later use Title

Data Analyser – Refraction error 26-Jan-09 Data Analyser – Refraction error Radio waves travel along slightly curved downwards trajectories Result= error in elevation and range Effect is negligible for all but low elevation angles and long ranges The RF coefficient of refraction changes exponentially with height – induced range error can be analysed and corrected Based on the Central Radio Propagation Laboratory (CRPL) standard atmosphere model Title

Data Analyser – Eccentricity error 26-Jan-09 Data Analyser – Eccentricity error Particularly important where radars have > 0.2 degrees peak to peak error Un-corrected error can contaminate analysis results Systematic error results Radar – radar analysis results Correction can be made based on gyroscope file, measured with the gyroscope measurement in RASS-S Select [eccentricity] on the data analyser to process results Title

Filter Filter on Timestamp Track number Scan number S-address A/C-code 26-Jan-09 Filter Filter on Timestamp Track number Scan number S-address A/C-code Range Azimuth Cubicle Filter structure: Different UNITS (turn on/off) Different groups Different conditions Relation between groups=AND/OR Save as local/global filter Filter window does not have to be open to be applied, the filter group only needs to be “ACTIVE”! Filter is for example used to remove non-synchronous data from the source – eg. internal targets (A1030), Track termination messages Use in combination with Data Analyser! For ADS-B targets filter on Figure of Merit (FOM) to exclude low quality data e.g. FOM>7 Title

26-Jan-09 RCD Operation flow Title

Outline RCD part of RASS-R Radar Comparator Dual – intro 26-Jan-09 Outline RCD part of RASS-R Radar Comparator Dual – intro Benefits and possibilities Operation Flow Parameter and node setup Data Analyser Filter Displays XY display Accuracy REF Accuracy RUT Statistics Practical use of RCM Module objectives Summary Title

Displays – XY Display XY display after trajectory reconstruction 26-Jan-09 Displays – XY Display XY display after trajectory reconstruction Display settings are similar to RCM Title

Displays - Accuracy REF/RUT Display 26-Jan-09 Displays - Accuracy REF/RUT Display Displays Accuracy REF (reference source) Accuracy RUT (radar under test) Display features Individual tracks are colored Identify problematic transponders Improve analysis accuracy by removing problem transponders Cursor information (links to table based statistics) REF and RUT accuracy is calculated against the reconstructed reference trajectory. This provides range/azimuth random errors for data from radar sources and X/Y random errors for ADS-B data sources Title

Info Window All info of a target (REF or RUT) 26-Jan-09 Info Window All info of a target (REF or RUT) Updated while cursor on graphs Selection of multiple items for easy recognition Title

Outline RCD part of RASS-R Radar Comparator Dual – intro 26-Jan-09 Outline RCD part of RASS-R Radar Comparator Dual – intro Benefits and possibilities Operation Flow Parameter and node setup Data Analyser Filter Displays Statistics Systematic and Random Errors Track Accuracy ADS-B Practical use of RCM Module objectives Summary Title

Statistics – Systematic and random errors 26-Jan-09 Statistics – Systematic and random errors General statistics Number of plots, tracks used in analysis (after filter applied) Radar Offset (radar sensors must be greater than 20NM apart for radar to radar comparison) Range/Azimuth Bias RMS Errors Corrections Applied Barometric Eccentricity Refraction Timestamp Timestamp Statistics Mono Radar estimates Title

Statistics – Track Accuracy 26-Jan-09 Statistics – Track Accuracy Statistics on trajectory based info Can be very useful to detect aircraft with anomalous transponder performance such as transponder delay. Similar results can also be measured with TRACKAN (RASS-R) Cursor linked with XY display Title

Statistics – ADS-B Significant parameters of ADS-B data 26-Jan-09 Statistics – ADS-B Significant parameters of ADS-B data Can be processed to a database containing Latency Mode-S delay FOM Measurement FOM Cursor linked with XY display Title

Practical use of RCD Measurement campaigns on radar sites 26-Jan-09 Practical use of RCD Measurement campaigns on radar sites Analyzing opportunity data to obtain systematic and random errors Analyzing flight checks: filter on A-code/S-address to obtain Pd of flight Usage of RASS-S may be required for detailed analysis for example Inventory tool For a gyroscope measurement Applications (as mentioned in the whitepaper “radar alignment and accuracy tool”) Radar evaluation and continous performance monitoring Barometric height error correction (3D height correction table) Radar radome influence evaluation and monopulse distortion correction Measurement of the azimuth errors generated by lightening poles Measurement of the beam widening of a LVA antenna 3D radar evaluation OBA lookup table correction ADS-B quality monitoring  refer to whitepaper on our website! Title

Module objectives State the major difference between the RCM and RCD 26-Jan-09 Module objectives State the major difference between the RCM and RCD State why ADS-B is the preferred data source for the reference node when making a RCD analysis Describe how accuracy information is derived for the “Accuracy REF” and “Accuracy RUT” displays State the four types of analysis that can be made with the Data Analyser in the RCD State how to apply “Time Stamp” correction to ADS-B reference data Describe the filtering requirements for ADS-B data that is used in the “reference” node of the RCD Title

26-Jan-09 Summary The RCD provides systematic error (bias) information by comparing two overlapping sources of information ADS-B information is a preferred source of information for the reference node as it contains true MSL height, has a high update rate, and has uniform positional errors. Information contained in the accuracy displays is derived by comparing the reference or RUT target position reports against the reconstructed trajectory from the object correlator The Data Analyser provides the following analyses of REF or RUT data: Timestamp error Eccentricity error Refraction error Barometric error Time stamp correction is applied by setting timestamp correction to “ON” under the reference Node information on the RCD main window. ADS-B reference data should be carefully filtered to remove target reports that have a low quality. This is achieved by filtering ADS- data with a low Figure Of Merit (FOM) Title