AGD SYSTEMS AGD315-207 AGD 315-207-000 Microwave Vehicle Detector User Manual AGD340

AGD SYSTEMS LTD AGD 315-207-000 Microwave Vehicle Detector AGD340

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without liability for errors or omissions. AGD315 User ManualPage 1 of 12

AGD315-205 and AGD315-207

RADAR USERS MANUAL

1 INTRODUCTION

These instructions detail the use and operation

of the AGD315-205 and -207 radars. This

radar has been specifically designed for the

accurate measurement of the speed and range

of passing vehicles when mounted at the side

of the road for enforcement purposes. The

radar is designed to work in conjunction with

an AGD340 radar plus a host, photographic

based, enforcement system. The host system

may be mobile or fixed location in nature.

The radar is supplied in a black plastic

enclosure which incorporates all the radar

circuitry and processing circuitry to perform the

speed and range measurement. The

connection to the radar is via a 1 metre cable

with multi-pin connector, and mounting is

provided by fixings on the housing.

The AGD315-205 is a 24.2GHz frequency

modulated continuous wave (FMCW) radar

whereas the AGD315-207 is a 24.125GHz

(24.075GHz-24.175GHz) radar which are

capable of measuring range and speed. The

radar’s integral planar antenna forms a narrow

beam which is sited at a predetermined angle

across the road. When vehicles pass through

the beam the radar accurately measures the

speed and range at a frame rate of 40

readings per second via an advanced digitising

and tracking technique to a resolution of

approximately 1 mph and 2 metres.

Details of each vehicle speed measurement

are passed to the host system via a high

speed serial communications interface.

Changes or modifications to this equipment,

not expressly approved by AGD Systems Ltd,

may void the user’s authority to operate this

equipment

Contents

1 INTRODUCTION

2 DOCUMENT REVISION

3 FMCW OVERVIEW

4 SPECIFICATIONS

5 SYSTEM HARDWARE OVERVIEW

6 MESSAGE FORMATS

7 RADAR USAGE

8 CABLE CONNECTIONS

9 TEST & CALIBRATION

without liability for errors or omissions. AGD315 User Manual Page 2 of 12

2 DOCUMENT REVISION

Issue

Amendment Details

Date of Issue

Initial Draft

23/12/2009

DCR3006 – added section relating to test and

calibration procedures. Figures and Tables

identified using auto-numbered captions.

14/06/2010

SCH

3 FMCW OVERVIEW

3.1 Basic Operating Principles of FMCW Radar

In an FMCW radar such as the AGD315-205/207, the following basic operating principles are applied:

The transmit signal is frequency modulated, normally by a linear modulation (a chirp)

The modulation of the received signal is compared to the modulation of the transmitted signal to

determine time delay and therefore range

velocity is determined by range differentiation or Doppler processing

Consider a signal transmitted from the radar at time t=0 and with frequency fstart. When this signal

strikes a target, the signal will be reflected back and received by the radar at a time t=tdelayed. During

the time of flight of the reflected signal. the transmit frequency will have increased to a new frequency

fdelayed, where fdelayed is given by the chirp rate and amplitude.

Hence at any instance in time after tdelayed, there is a difference in frequency between the transmitted

and received frequencies. This frequency difference is proportional to the time of flight for the

received signal, and since the radar signal travels at the speed of light (a constant), the time of flight is

also proportional to the range of the target which reflected the radar signal.

In an FMCW system, the transmit and receive signals are compared using an RF Mixer. The mixer is

driven by the transmit and receive signals, and the mixer output is the difference between the two

input signals. The output signal is referred to as the intermediate frequency (IF).

If the IF is sampled into an analogue to digital converter (ADC) at fixed time intervals during a single

excursion of the frequency modulation (one period of the chirp) and the resultant digital signal is

viewed in the frequency domain, a number of different frequencies will be seen, where each frequency

corresponds to a target at a particular range.

If data from a number of successive chirps is gathered and processed, speed and range for individual

targets can be determined.

without liability for errors or omissions. AGD315 User Manual Page 3 of 12

4 SPECIFICATIONS

Radar General

Items

Specification

Notes

Housing

Black UV stabilised polycarbonate

Fine spark finish

Radar Weight

0.80 Kg

Including 1 metre lead and connector

External

Dimensions

160mm(W) x 130mm(H) x

60mm(D)

Mounting

Fixings

4 x M4 threaded inserts

M16 cable gland

Sealing

IP66

Radar

Connection

9 pin Bulgin Bucanneer (male)

attached to end of 1 metre lead

Bulgin PX0728/P

See section 9 for more information

Radar Labelling

Manufacturer’s Label

LED

Red status indicator LED

Blue ‘Bluetooth’ indicator LED

Radar Power Connection

Parameter

Specified

Tolerance

Notes

Supply Voltage

24V dc

9-30V

Current

263mA

10%

At 12Vdc

Radar Data Connection

Parameter

Specified

Notes

4 wire RS 422

See extra notes on data connection and

BAUD command.

without liability for errors or omissions. AGD315 User Manual Page 4 of 12

Environmental Performance

Test

Severity

Specification

Cold

(-20 C Operational)

IEC 68-2-1 Test Ab

Dry Heat

+60 C Operational

IEC 68-2-2 Test Bb

Damp Heat

Cyclic 48Hrs 25 C to 40 C 95%RH

IEC 68-2-30 Test Db

Free Fall

Each top rear corner & each top

rear face. 1000mm free fall to

concrete.

IEC 68-2-32 Test Ed

Drop and

Topple

All faces & corners 100mm drop

IEC 68-2-31 Test Ec

Shock

4000m/S2, 2mS Duration

IEC 68-2-27 Test Ea

Random

Vibration

0.02g2/ Hz (10-50Hz)

0.01g2/ Hz (50-150Hz)

0.002g2/ Hz (150-500Hz)

Overall RMS 1.58g 3Hrs on X,Y,Z

axes

IEC 68-2-34 Test Fd

Sinusoidal

Vibration

5-7Hz 1.5mm

7-35Hz 10m/S2

IEC 68-2-6 Test Fc

Bump

1000 in X,Y,Z axes 100m/S2,16mS

IEC 68-2-29 TestEb

Immersion

Preconditioned to +30 C over

ambient before 12Hrs Immersion.

IEC 68-2-18 Test R

Radar Transceiver

Component

Specification

Notes

Antenna

Planar patch array

Transmitter

Quarter wave resonator

Receiver

Homodyne I Q down converter

Radome

Black UV stabilised polycarbonate

Radar Transmission

Parameter

Specified

Notes

Radar Centre

Frequency

24.200 GHz UK/EU/AS/NZS

24.125GHz USA

Modulation

Bandwidth

80MHz

Operating

Frequency Band

24.150 - 24.250GHz (UK/EU/AS/NZS)

24.075 – 24.175GHz (USAVersion)

Modulation bandwidth of ~80MHz plus

temperature stability guard bands (+/-

10MHz)

Fundamental

Frequency Power

<20dBm EIRP

Fundamental

Frequency Field

Strength

<1000mV/m

@3m

Frequency

Temperature

Stability

Typically < 1 MHz/ C

Uncompensated

Polarisation

Plane polarised with E-Field vertical

Horizontal

Beamwidth

7 degrees

without liability for errors or omissions. AGD315 User Manual Page 5 of 12

Vertical

Beamwidth

28 degrees

Spurious

< 1 W EIRP (25 to 22000MHz)

Emission Code

80M0FXN

ITU Designation

Antenna Sidelobe

Suppression

>15dB

Radar Detection

Parameter

Specified

Notes

FFT size

256 point

Tracking window

Not Applicable

Image Rejection

Not Applicable

Measurement rate

40 Hz

The number of speed \ range

measurements made per second

Technical Performance Specifications

Radio

Specifications

ETS300.440, AS/NZS4268

FCC 47CFR15.245

without liability for errors or omissions. AGD315 User Manual Page 6 of 12

5 SYSTEM HARDWARE OVERVIEW

A simplified block diagram of the AGD315-205/207 is shown below:

4k x 18 bit

FIFOS

12 bit ADC

Radar Transceiver Module

DDS \ DAC Amplifier

& Filter

Subsystem

PIC 18F452 TI C6711 DSP & associated

components (SDRAM,

FLASH etc)

Power Supplies

Figure 1 System Hardware Overview

5.1.1 Serial interface, RS422

A UART interface is provided using RS422 voltage levels, over a 4 wire (full duplex) interface. The

default baud rate for this interface is 115200. This may be changed using the BAUD command to

speeds of up to 921600. The BAUD command will store the baud rate into non volatile memory of the

radar ready for the next time the radar boots.

The serial interface default setup during normal operation is shown in Table 1.

without liability for errors or omissions. AGD315 User Manual Page 7 of 12

Parameter

Value

Baud rate

115200

Data bits

Parity bits

None

Stop bits

Flow control

None

Table 1 Default UART Settings

The RS422 provides the primary output of the radar in the form of ASCII messages. These messages

provide speed and range information.

5.1.2 LED’s

No LED’s are visible from the outside of the unit. A number of internal LED’s are provided for test and

debug purposes.

5.1.3 Temperature Sensor

A digital temperature sensor has been installed on the digitiser board. This allows the processor to

monitor environmental conditions. The temperature of the radar may be requested using the TEMP

command.

5.1.4 Non Volatile Memory

An EEPROM is installed on the board to provide non volatile memory. The primary use of this

EEPROM is to store configuration and calibration data.

5.2 Power supply board CB-180

The radar is powered using a DC voltage in the range of 9 to 30 volts. The radar is polarity protected

using a diode. The radar can take a very large current doing power up that is of the order of amps.

However, this current only lasts for ~1ms and should not affect most applications.

5.2.1 Input Protection

A one shot anti-surge (T) fuse with a 630mA rating has been installed to protect against electrical

short circuit fault conditions.

without liability for errors or omissions. AGD315 User Manual Page 8 of 12

6 MESSAGE FORMATS

6.1 Standard Messages

In normal operation, the radar produces a single standard message of the following form

<frame number>,<radar mode>,<detection direction>,

A sample message sequence from a typical roadside test is shown below:

0001917903,R,A,22: #T0:A,29,11,11.7,70.3

0001917904,R,A,22: #T0:A,29,11,11.7,60.4

0001917905,R,A,22: #T0:A,29,11,11.7,65.5

0001917906,R,A,22: #T0:A,29,12,12.8,61.0

0001917907,R,A,22: #T0:A,29,12,12.8,66.1

0001917908,R,A,22: #T0:A,28,12,12.8,68.4

0001917909,R,A,22: #T0:A,28,13,13.8,65.5

0001917910,R,A,22: #T0:A,28,12,12.8,67.3

0001917911,R,A,22: #T0:A,27,13,13.8,63.0

0001917912,R,A,22: #T0:A,28,13,13.8,71.2

The fields in each message are described in the table below:

Field Descriptor

Explanation

Comments

Frame number

Increments every frame

Reset if detector is rebooted

Radar Mode

R – ranging mode

Factory set by AGD

Detection direction

Advance, Recede, Bidirectional

See section 8 – radar usage

Cosine correction

Mounting angle to the road

Debug into

Between : and !

AGD use only

Target Information

Target number, Direction, Range

bin, Doppler Bin, Speed,

Power Level

Range bin = 2 metres

Doppler bin = ~1 mph

Speed includes cosine correction

and is in either mph or kph

Table 2 Message Descriptors

Notes:

Speed – vehicle speed will be modified by the cosine of the dominant detector mounting

angle. Use the *AD<space><angle><cr> command to set the mounting angle of the

detector relative to the road surface, and use UNITS<space>MPH<cr> or

UNITS<space>KPH<cr> to set the measurement units.

The fundamental unit of speed measurement is the Doppler bin, which is approximately equal

to 1mph, so the speed resolution of the radar cannot be any better than this, no matter what

units are selected.

without liability for errors or omissions. AGD315 User Manual Page 9 of 12

7 RADAR USAGE

7.1 Introduction

For best detection performance the radar must be setup correctly. Failure to do so can result in

inaccurate or false detections.

7.2 System Integration

The AGD315-205/207 has been designed to be used in conjunction with the AGD340 and a host

system. It is the responsibility of the supplier of the host system to ensure that data fusion \ correlation

of the speed and range data from the AGD315-205/207 and speed data from the AGD340 is done in

such a manner as to be ‘fit for purpose’.

7.3 Radar Mounting Angle

Radars are supplied factory programmed to be used for a specific mounting angle, usually to 22

degrees. This angle is the angle the radar points across the road from the direction of the road, see

Error! Reference source not found.. The angle is also reported in all output messages and the

command *AD may be used to determine it. This angle is used by the radar to adjust the speed the

radar measures to the actual target speed and therefore it is important the radar is setup with the

correct angle. If the radar is setup with an angle that is less than the mounting angle then the radar will

measure speeds that are larger than the vehicles true speed, while if the angle is greater than the

mounting angle the radar will measure speeds that are less than the vehicles true speed.

22o

Figure 2 Radar Mounting Angle

The radar transmits a radio beam across the road that has a horizontal beam width of ~7 degrees. The

vertical beam width of the radar beam is relatively large at 28degrees so although the radar should be

made level this is not crucial for correct operation. For a fixed camera installation often the radar is

mounted relatively high (~3m) and in this case it is desirable to point the radar more down towards the

ground. In this application careful consideration of the radar beam and its shape is required to ensure

that all the lanes of the road are covered.

without liability for errors or omissions. AGD315 User Manual Page 10 of 12

7.4 Maximum Speed Measurement

Normally, the radar can detect targets travelling in both directions simultaneously (if required) at

speeds of up to 128mph. The radar can resolve the speed to the nearest Doppler bin, which is

approximately equal to 1mph.

In some situations, it may be required that the radar measure higher target speeds than 128mph. It is

possible to configure the radar to measure targets up to 255mph, but with the caveat that the radar

must be set into either advance or recede mode (not bidirectional), and targets travelling in the wrong

direction at sufficient speed will generate erroneous speed readings which appear to have come from

the required direction.

For example, if the radar is set into advance mode, and the command *RV<space>150<cr> is sent

to the radar, the following behaviour will be seen:

Vehicle

Speed (mph)

Vehicle

Direction

Radar Operation

0 – 10

Approach

Vehicle not detected, speed is below the low speed cutoff

10 – 150

Approach

Vehicle detected, speed and direction measured correctly, message sent

150+

Approach

Vehicle not detected, speed is above upper limit set by *RV

0 – 10

Recede

Vehicle not detected, speed is below the low speed cutoff

10-105

Recede

Vehicle detected, speed and direction measured correctly, no message

105+

Recede

Vehicle detected, speed and direction measured incorrectly, message sent

Table 3 Maximum Speed Behaviour

So, the *RV command is used to set the maximum speed measurable in the required direction. Under

most situations, the erroneous speed measured can be filtered out because the range measurement

will be incorrect.

One situation where the range cannot be used to filter out erroneous targets is for a vehicle driving the

wrong way down the road at excessive speed (for example, a vehicle driving the wrong way down a

dual carriageway or motorway). However, two radars deployed at the same position, one set to

approach and one set to recede, both with the same *RV setting could be used under these

circumstances, which would give the capability to measure up to ±255mph (255mmph approach with

one radar, 255mph recede with the other). Under most normal situations however, a single radar will

the capability for ±128mph should be sufficient.

without liability for errors or omissions. AGD315 User Manual Page 11 of 12

8 CABLE CONNECTIONS

The AGD315-205/207 connections are shown in the table below:

Pin No.

Wire Colour

Function

Power Off

Power On -

No Detect

Power On -

Detect

Orange \ White

24v ac or 12-24v dc

White \ Orange

24v ac or 0v dc

Green

Earth / Ground

Blue \ White

Detector RS422 Y

Brown \ White

Relay Common

White \ Brown

Relay Contact

N/C

N/O

N/C

White \ Blue

Detector RS422 Z

White \ Green

Detector RS422 B

Green \ White

Detector RS422 A

Table 4 Cable Connections

9 TEST & CALIBRATION

9.1 Overview

The AGD315-205207 is subjected to rigorous build, calibration and test procedures. These procedures

are designed to provide a simple set of pass and fail criteria for production operatives to ensure

standardisation in the delivered product, isolate faults so they can be identified and fixed prior to unit

shipment, and to weed out infant mortality failures in components.

9.2 Configuration Of User Settings

Once a unit has been calibrated, a number of specified settings are adjusted, and further tests are

carried out to ensure the unit is operating within acceptable limits (please refer to Figure 3 overleaf).

Table 5 summarises the user settings which are adjusted, showing the tests carried out, and the pass

\ fail criteria applied to each test.

Test

Description

Pass \ Fail Limits

Comments

Check for correct operation of RS422

Receive OK

Transmit OK

At 115200 baud

Check serial number via RS422 port

Same as serial number

set previously

Serial number cannot

be adjusted via RS422

for security

Message OK

Frame rate 40FPS

Cosine set to 22º

Message should start

automatically on power

Table 5 User Settings

without liability for errors or omissions. AGD315 User Manual Page 12 of 12

Figure 3 shows the process by which the user settings are configured:

Set ranging mode

Set 40 FPS

Set 22 degrees

(via LW port)

Enter serial

number

xxxxx-yyyyy

(via LW port)

Reboot unit

RS422 OK ?

YES

START

Unit

calibrated ? Calibrate unit

YES

Values stored in

parameter

EEPROM

Connect to unit via

Livewire port

Values stored in

secure

EEPROM

Enable

RS422 port

Set baud rate

(115200)

Check

serial number

(via RS422 port)

FAIL (TEST 11)

xxxxx-yyyyy from

secure EEPROM

Serial

number OK

YES

NO FAIL (TEST 12)

Enable ranging

diagnostic

message

Reboot unit

Message OK ?

YES

NO FAIL (TEST 13)

END

TEST

Figure 3 Configuration Of User Settings

AGD SYSTEMS AGD315-207 AGD 315-207-000 Microwave Vehicle Detector User Manual AGD340

AGD SYSTEMS LTD AGD 315-207-000 Microwave Vehicle Detector AGD340

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