Direct RF Sampling Transceiver Architecture

Applied to VHF Radio, ACARS, and ELTs

DASC 2017September 20, 2017

Session IMA-4:

Interpartition Communication

1

Anh-Quang Nguyen, Alireza Avakh Kisomi, Abdessamad Amrhar

and René Jr. Landry

Outline

1. Introduction

2. DRFS Transceiver Architecture Overview

a. Reception

b. Transmission

c. ELT Detectors

3. Result analysis

4. Conclusion and Future work

5. Appendix: Reveal future results

2DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

1. Introduction

3DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

1. Introduction

Today’s Avionic Systems

4DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

• Multiple dedicated antenna

• Multiple rack mount avionics

• Kilometers of cables and connectors

1. Introduction

Proposed Avionic Systems

5DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

Advantages :

Less equipment and cables

Hardware to software redundancy

Software function reallocation

Easier maintenance

Lower cost

SDAR SDAR SDAR SDAR SDAR

SDAR

SDAR SDAR SDAR

SDAR

Software

Defined

Avionic

Radio

Multi-Standard Antenna

Short Cables

Reconfigurable Software Defined Radio

Fiber Optic Network

AVIO-505 Vision

ICNS 2017 Frequency Tracking System for Direct RF Sampling Architecture Applied to VHF Avionic Radios 6DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

1. Introduction

Context of the AVIO-505 Project

• Objectives:

– Integration of navigation, communication and surveillance systems under a

single universal reconfigurable platform

– Demonstrate the capabilities and performance of SDR in aerospace

– Address new regulatory initiatives (NextGen)

1. Introduction

AVIO-505: MM-SDAR Architecture

7

Antenna switch matrix

Ant.1

Ant.2

Ant.m

RF front end

Tranceiver FPGA GPP

App. 1

App. 2

App. n

RF filtering &amplification

Antennas switching & duplexing

RF conversion &ADC/DAC

Rate conversion & BB DSP

FunctionApplications execution & interfacing

Avionics interface

Cockpitinterface

PicoSDR2x2E

DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

Source: Multi-mode reconfigurable software

defined radio (SDR) architecture for avionic

radios

- 2017 Integrated Communications, Navigation and

Surveillance Conference (ICNS)

1. Introduction

AVIO-505: Direct RF Sampling

• Direct RF Sampling (DRFS) Architecture

8ICNS 2017 Frequency Tracking System for Direct RF Sampling Architecture Applied to VHF Avionic Radios

VHF

RadioACARS

VOR LOC G/S

SDAR

(DRFS)Others

ELT

DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

Antenna +

Filters +

Combiner

DDC

FPGA

General Purpose

Processing Unit

(GNU Radio)

Pre-Processing Unit

DRFS architecture

ADC

Antenna +

Filters General Purpose

Processing Unit

Pre-Processing

Unit

IF

Filters

ADC

DDC

DDC

Conventional architecture

ADC

Mixer

LO

Mixer

IF Stages

1. Introduction

Direct RF Sampling basics (RX)

9ICNS 2017 Frequency Tracking System for Direct RF Sampling Architecture Applied to VHF Avionic Radios

• Sampling GHz signal with MHz sampling rate

• Processing multiple signals with one ADC

ADC ADS62P49

Sampling Rate 140 MHz

Resolution 14 bits

DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

VHF Avionics

(VOR, Localizer

(ILS), VHF

Radio, ACARS,

Analog ELT)

108 – 140 MHz

Digital ELT

406.025

MHz

Glide Slope

329.15 –

335 MHz

1. Introduction

Direct RF Sampling basics (TX)

10ICNS 2017 Frequency Tracking System for Direct RF Sampling Architecture Applied to VHF Avionic Radios

• Use Digital Mixer/Interpolation Filter to Up-Convert the signal

before a high sampling rate DAC.

DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

Antenna and

Analog

Components

General

Purpose

Processor

Transmission Flow

DAC 1 RTDEx 1Converter

140 Msps 200 ksps

`

CIC

Application

Selector

CICDigital

MixerDAC 2

Digital

Mixer

ADCDigital

Mixer

DAGC

DAGC

CICFIR

(B=10 kHz)RTDEx 1Converter

CIC

ACARS

I&Q

VHF I&Q

140 Msps 200 ksps

ACARS

Frequency

VHF

Frequency

FIR

(B=5 kHz)

Reception Flow

RTDEx 2Converter

RTDEx 2Converter

1. Introduction

Challenges and Objectives (1/2)

11ICNS 2017 Frequency Tracking System for Direct RF Sampling Architecture Applied to VHF Avionic Radios

• The variety of Signal of

Interest and Bidirectional

application

DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

ACARS

- Bidirectional

Application

- MSK

Modulation

- Message

Digital ELT

- FSK

Modulation

- GPS Data

- Message

Analog ELT

- Amplitude

Modulation

- Frequency

Sweeping

technique

VHF Radio

- Bidirectional

Application

- AM

• Direct RF Sampling Approach

Alias in transmission

High Q Analog Filter

1. Introduction

Challenges and Objectives (2/2)

12ICNS 2017 Frequency Tracking System for Direct RF Sampling Architecture Applied to VHF Avionic RadiosDASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

• Analog ELT Detection with FFT

Performance FPGA Resource

• GPP resource

ACARS Performance

GPP ResourceVHF Radio Performance

Other Systems

2. Architecture Overview

13ICNS 2017 Frequency Tracking System for Direct RF Sampling Architecture Applied to VHF Avionic RadiosDASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

2. Architecture Overview (1/3)

GPP – GNU Radio

14ICNS 2017 Frequency Tracking System for Direct RF Sampling Architecture Applied to VHF Avionic RadiosDASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

Encoder FSK ModUp

SamplingGPS data

Encoder MSK ModUp

SamplingMessage

SelectorTo

FPGA

Transmission (For example: Digital ELT, ACARS branch)

Reception (ACARS and VHF Radios)

From

FPGA

MSK

DemodDecoder

CRC and

Parity Bit

Check

Resampler

+ Filter

Message

Handler

Resampler

+ Filter

AM

DemodAudio

HandlerSelector

Resampler

+ Filter

AM

Demod

2. Architecture Overview (2/3)

FPGA – System Generator

15ICNS 2017 Frequency Tracking System for Direct RF Sampling Architecture Applied to VHF Avionic RadiosDASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

ADC

GPP

DAC

AGCDigital

MixerCIC/FIR

AGCDigital

MixerCIC/FIR

Digital

Mixer

Interpolation

Filter

Frequency Selector

Interpolation

FilterDigital

MixerDAC

2. Architecture Overview (3/3)

ELT Detector Implementation

16Frequency Tracking System for Direct RF Sampling Architecture Applied to VHF Avionic RadiosDASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

ADCDigital

Down

Converter

Digital

Down

Converter

FFT

Core

FFT

Core

Detector

• 16384 FFT points

• ADC rate: 140 Msps

• DDC decimation rate: 700

• Low IF offset: 3 kHz and

10 kHz

Algorithm in Detector

• Look for ELT signals in a specific

range of FFT pins

• Detect sweep tone Counter

• Compare count value with a

threshold Trigger

101- 153

Carrier position

FFT pin

range

Low Sweep

Range

High Sweep

Range

3. Performance Analysis

17ICNS 2017 Frequency Tracking System for Direct RF Sampling Architecture Applied to VHF Avionic RadiosDASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

4. Performance analysis (1/6)

Equipment and Testbench

18DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

3. Performance analysis (2/6)

VHF Radio (TX/RX)

19DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

Standard (Class 4)System

Performance

Output Power ≈ 36 dBm - 6 dBm

Offset ≤ 4 kHz ≤ 1.5 kHz

SINAD 6 dB 21.22 dB

S/N in Carrier ≥ 35 dB ≥ 70 dB

Baseband 350 – 3200 Hz 300 – 3200 Hz

3. Performance analysis (3/6)

ACARS (TX/RX)

20DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

TX one tone

(2400 Hz)

Output Power ≈ -6.35 dBm

Offset 580 .97 Hz

Gain Imbalance 0 dB

SNR 9.5 dB

Decode Result All “1”

3. Performance analysis (4/6)

ELT 406.025 MHz

21DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

Standard System

Performance

Offset ≤ 2 kHz ≤ 500 Hz

Rate47.5 – 52.5

seconds

49 – 51

seconds

Length 520 ms ± 1% 517 ms

Delay From

Trigger≤ 5 minutes ≤ 1 minute

Resolution 4 seconds ≤ 3 seconds

3. Performance analysis (5/6)

ELT 121.5 MHz

22DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

Standard System

Performance

Offset ≤ 607 Hz ≤ 10 Hz

Sweep

Frequency1600 – 300 Hz 1444 – 706 Hz

Sweep

Range≥ 700 Hz 734 Hz

Duty Cycle 0.33 – 0.55 0.5

Modulation

Factor≥ 0.85 ≥ 0.99

3. Performance analysis (6/6)

ELT 121.5 Detector in DRFS

23DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

LevelAverage

Detection TimeDetection

Rate

−20 dBm 1.53 s 100 %

−35 dBm 13.82 s 100 %

−65 dBm 20.57 s 100 %

−80 dBm 22.32 s 100 %

−100 dBm 13.62 s 100 %

USRP

(Transmitter)

PicoDigitizer

4. Conclusion and Future

work

24DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

4. Conclusion and Future work (1/2)

25DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

• DRFS Architecture for aviation is a promising

approach

– Offers a major simplicity to the current RF Avionics

– Increases the integration level of avionic modules

– Increases the efficiency of Size, Weight, Power and Cost.

– Has a performance similar or even higher than the current

RF architecture.

– Can contain various background applications (for example,

ELT Detector), without the need of extra analog

components.

• DRFS Architecture offers the advantages in both

Transmission and Reception

ICNS 2017 Frequency Tracking System for Direct RF Sampling Architecture Applied to VHF Avionic Radios 26

4. Conclusion and Future work (2/2)

• Verify the functionality of ACARS using verified equipment

• Continue testing and further improve the ELT Detector.

• Study the possibility of integrating more applications

ADS-B In at −60 dBm

(IFR 6000)

DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

5. Appendix: DRFS Flight

Tests

27DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

ICNS 2017 Frequency Tracking System for Direct RF Sampling Architecture Applied to VHF Avionic Radios 28

5. Appendix (1/3)

DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

12/2015

3/2016

10/2016

4/2017

5/2017

Next Step ??

Flight TestsSpectrum Validation

VOR

VOR, VHF Radio RX

2 VOR, 2 VHF Radios RX, VHF Radio TX, ELT 121.5

2 VOR, LOC, GS, 2 VHF Radios RX

ICNS 2017 Frequency Tracking System for Direct RF Sampling Architecture Applied to VHF Avionic Radios 29

5. Appendix (2/3)

DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

ICNS 2017 Frequency Tracking System for Direct RF Sampling Architecture Applied to VHF Avionic Radios 30

5. Appendix (3/3)

DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs

1

2

3

4

Questions?

Thank you

31

Contact us at LASSENA:

Anh-Quang NGUYEN

Anh-Quang.Nguyen@lassena.etsmtl.ca

DASC 2017 Direct RF Sampling Transceiver Architecture Applied to VHF Radio, ACARS, and ELTs