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

2. 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

3. 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

4. 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

5. 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

6. 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

7. 26-Jan-09
RCD Operation flow (1)
Title

8. 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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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

18. 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

19. 26-Jan-09
RCD Operation flow
Title

20. 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

21. 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

22. 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

23. 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

24. 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

25. 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

26. 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

27. 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

28. 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

29. 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

30. 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