EU PROJECT RESOLUTION

Reconfigurable Systems for Mobile Local Communication and Positioning

Frank Ellinger*, Jörg Carls*, Silvan Wehrli, Heinz Jäckel, Christian Kromer

Electronics Laboratory, Swiss Federal Institute of Technology (ETH) Zürich, Switzerland

*Will be with the Chair for Circuit Design and Network Theory, Dresden University of Technology,

Helmholzstrasse 10, Dresden, Germany,

Leif Wiebking, Alexander Dabek, Jörg Hüttner, Richard Roskosch, Roland Gierlich,

Claus Seisenberger

Power & Sensor Systems, Siemens, Munich, Germany

Mario Huemer, Ralf Mosshammer, Thomas Uβmüller, Robert Weigel

Institute of Electronics Engineering, Friedrich Alexander University of Erlangen-Nuremburg, Erlangen, Germany

Viswanathan Subramanian, Marko Krcmar, Georg Böck

Microwave Engineering Group, Technical University of Berlin, Germany

Demosthenes Doumenis, Anastasis Kounoudes

SignalGeneriX Ltd, Limassol, Cyprus

Krzysztof Kurek, Yevhen Yashchyshyn, Rafal Szumny

Warsaw University of Technology, Poland

Antonis Kalis

Research and Education Society in Information Technologies, Athens, Greece

Elena Avatagelou, Anastasia Garbi

Exodus, Athens, Greece

Solon Spiegel

RIO Systems, Tel Aviv, Israel

Keywords: Local positioning, FMCW radar, RF, WLAN, integrated circuits, CMOS, BiCMOS.

Abstract: This conference paper gives a brief overview of the EU project RESOLUTION started in Feb. 2006. The

goal is the development of a wireless three-dimensional (3-D) local positioning system with measurement

accuracy in the centimeter regime. A novel frequency modulated continuous wave (FMCW) radar principle

with active sensors is employed. This advanced local position radar will be co-designed together with

common WLAN systems operating around 5 GHz. Because of the high positioning accuracy, real-time

ability, and robustness against multipath effects and fading, novel applications will be feasible including

smart factories, robotics, interactive guiding, object tracking and augmented reality.

1 INTRODUCTION

Since more than 50 years, radar based on the

transmission and detection of RF waves is employed

to locate plains, ships and submarines (James, 1989).

Today, positioning services have been expanded and

enhanced for guiding of cars and pedestrians,

interactive maps, automated factories, robotics,

augmented reality, etc. The following positioning

methods are commonly used:

362

Ellinger F., Carls J., Wehrli S., Jäckel H., Kromer C., Wiebking L., Dabek A., Hüttner J., Roskosch R., Gierlich R., Seisenberger C., Huemer M.,

Mosshammer R., Ußmüller T., Weigel R., Subramanian V., Krcmar M., Böck G., Doumenis D., Kounoudes A., Kurek K., Yashchyshyn Y., Szumny R.,

Kalis A., Avatagelou E., Garbi A. and Spiegel S. (2006).

EU PROJECT RESOLUTION - Reconﬁgurable Systems for Mobile Local Communication and Positioning.

In Proceedings of the International Conference on Wireless Information Networks and Systems, pages 362-367

DOI: 10.5220/0002094203620367

 SciTePress

• GPS (Global Positioning System) based on

trilateralisation methods associated with satellites

acting as reference transmitters.

• Cell-ID (Identification): position is estimated by

means of the closest basestation.

• RSS (Received Signal Strength): distance d

between reference transmitter and object is

determined by the propagation loss being

proportional to

with n as channel-specific

parameter.

• TOA (Time of Arrival): with given signal

velocity c, d is measured with respect to the time

difference

t between transmitted and reflected

signal:

dct

=⋅⋅ . (1)

• AOA (Angle of Arrival) by means of goniometry

considering the angles of the signals.

Detailed information about positioning principles

can be found in [Vos03, Sko90, Ell06].

Figure 1: Positioning accuracy and coverage range of

systems merging mobile communication and positioning,

AOA: angle of arrival, HPLS: high precision localization

system based on FMCW.

There is the trend to combine radio-location and

mobile communications yielding enhanced and

novel services. Examples of such systems are:

• GPS and GSM/3G

• Cell-ID and GSM/3G

• RSS and WLAN

• TOA/AOA and UWB

In Figure 1, the positioning accuracies and coverage

ranges of these approaches are illustrated.

A novel positioning system based on FMCW

radar is developed in the framework of

RESOLUTION. First feasibility studies have

indicated 3-D positioning accuracies in the

centimeter regime. This would significantly enhance

the state-of-the-art in terms of local positioning

accuracy. Further advantages are real-time ability

and self-sustaining operation independent on any

external operator.

2 FMCW RADAR

Different FMCW systems will be considered in the

RESOLUTION project. Potential approaches are

discussed in the next paragraphs. The final choice of

the architecture will be chosen with respect to

market specifications.

2.1 Functionality

In Figure 2, a basic approach of a FMCW

positioning radar is illustrated. An oscillator is

modulated by a ramp generator yielding a reference

signal, which is transmitted and reflected back. The

transmitted and reflected signals are denoted by LO

and RF, respectively.

Figure 2: Functional principle of FMCW radar for

positioning, TX: transmitter, RX: receiver.

Due to the time delay

t, the two signals have a

frequency offset f

, which can be extracted by

mixing. Suppose that the mixer acts as frequency

subtractor yielding

IF LO RF

− . (2)

VCO

Circ-

ulato

Mixe

Ramp

generator

TX mode

RX mode

Filte

max

min

Indoor

Outdoor

local

Outdoor

global

RESOLUTION

GPS

Galileo

DGPS +

GSM/3G

Cell-ID +

GSM/3G

Positioning

mobile communication

0.1 0.3 1 10 30 100 1k 3k

0.1 1 10 100 1k 10k

Positioning accuracy [m]

Coverage range [m]

Tracking

Routing

Guiding

utomation

Enhanced guiding

ugmented reality

Field-strength +

WLAN, Bluetooth

TOA/

AOA

UWB

HPLS +

802.11

a/n

EU PROJECT RESOLUTION - Reconfigurable Systems for Mobile Local Communication and Positioning

363

Attributed to the linear dependence between d,

and f

, the distance can be determined by

df∼ . (3)

According to Figure 3 we can identify three types of

reflections. First, the desired one carrying the

distance information. Second, unwanted multipath

reflections. In the FMCW based approach, a major

part of the mutipath components can be suppressed

by lowpass filters, since the delayed multipath

components have a higher IF frequency than the

target object. Third, we have to consider reflections

at undesired objects not hitting the target object.

Approaches solving the latter problem are proposed

in the next sections.

Figure 3: Types of reflections.

2.2 Basestations with Active

Reflectors

This system consists of a basesation acting as

transmitter and a compact and low-power

consuming active sensor serving as reflector. In

Figure 4, the schematic of the reflector is illustrated.

Figure 4: Active reflector with modulated signal.

The feedback amplifier acts as oscillator excited

with the frequency of the input signal. By

modulating the reflector, the reflected signal is

associated with a specified modulation frequency

mod

. After filtering, the distance can be extracted on

basis of the spacing between the two remaining

frequency components located around f

mod

. The

corresponding relation yields (Wiebking, 2003)

mod

8BW

⋅

(4)

with

f being the frequency offset of the frequency

components located around f

mod

, and the bandwidth

BW. Multiple objects can be detected by choosing

different modulation frequencies.

Figure 5: Active reflector with modulated and pulsed

signal.

Active sensor topologies allow amplitude recovery

of the signal resulting in enhanced coverage range.

However, the measurement accuracy is limited by

the jitter inherent in the reflector. By pulsing the

modulated reflector, this jitter can be reduced. The

corresponding circuit schematic is outlined in

Figure 5. Note that at every switch-on, the oscillator

frequency is coherent with respect to the input

frequency. Consequently, the signal frequency is

recovered at every pulse cycle.

2.3 Synchronized Frequency Ramps

The latter approach applies a compact, light-weight

and low-cost sensor, which is advantageous.

However, this sensor is not capable to act as

transmitter. A solution with equal transceiver

stations allowing for both transmit (master) and

reflect (slave) function may be favourable for many

applications. Efficient signal recovery can be

performed in the reflector station. To enhance the

performance, the incoming and outgoing signals are

synchronized in the reflector. As for the latter

approach, the distinction with respect to other

objects may be performed by signal modulation or

adding of an identification signal.

2.4 Conclusions

We can conclude that FMCW based positioning

approaches with active sensors are capable to

provide the following advantages:

Pulse

Delay

Modulation

mod

Delay

Modulation

mod

Target

TX/RX

REF2

REF1

Desired

Undesired

mutipath

Undesired

target

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• High measurement accuracy due to extraction in

the frequency domain.

• We can clearly distinguish between target and

arbitrary objects.

• Detection of multiple objects is possible.

• Efficient rejection of multipath effects by means

of lowpass filtering in the frequency domain.

• Enlargement of coverage range by signal

recovery.

However, we also have to mention the following

disadvantages compared to approaches with passive

reflectors:

• Active sensors consume dc power and require a

battery.

• The complexity and costs are higher.

For many applications such as smart factories and

interactive guiding, the latter properties are not a

problem.

3 PARTNERS AND TASKS

The consortium combines multidisciplinary

competences and resources from academia and

industry including market-oriented service

providers. It consists of 1 large enterprise, 3

small/medium size enterprises, 1 research institute

and 5 universities, from 4 EU countries (2 of them

new EU countries) and one associated EU country.

Details including the key tasks of each partner are

outlined in Table 1.

4 APPLICATIONS

The developed positioning system does not require

any external service provider and can be applied for

various applications. Two examples are smart

factories and interactive guiding.

4.1 Smart Factories

A smart factory is based on knowing the position of

every workpiece, fabrication tool, transport

machinery or maintenance worker at any time and

everywhere. Position tracking performed by a host

enables several exciting new features:

• Complete overview over the location and amount

of all supplies and tools included in the

manufacturing process.

• By virtue of wireless networks, real-time data

access is possible anywhere and anytime.

• Due to information transfer enhanced global

management and product state monitoring is

possible.

• The level of automated fabrication can be

increased.

• Optimization of material flow and resource

delivery.

• Less storage area and material consumption.

• Reduced fabrication time.

• Efficient use of fabrication tools and machines.

• Collision avoidance and increased security.

Table 1: Partners and tasks.

Partner Core Role and Competence

1a. Swiss Federal Institute of Technology

(ETH) Zürich, Switzerland, U

Preparations/proposal writing

CMOS RF reflector design

1b. Dresden University of Technology*

Coordination

CMOS RF transmitter design

2. Siemens AG, Germany, LE Economic exploitation smart factories

Demonstrator design

Associate and market relevant project management

3. Technical University of Berlin, Germany, U CMOS RF receiver design

Experience with reconfigurable systems

4. University of Erlangen-Nuremberg,

Germany, U

System engineering and simulations

CMOS fractional-n synthesizers

5. RIO System, Israel, SME Linearization and smart power control of power amplifiers

6. Signal Generix, Cyprus, SME Signal processing, FPGA and baseband implementations

7. Warsaw University of Technology, Poland,

Antennas

Basic channel characterization and modeling

8. EXODUS S.A., Greece, SME Economic exploitation cultural and interactive guiding

9. Research and Educational Society in

Information Technology, RI

Algorithms for adaptive antenna combining including implementations

LE: large enterprise, SME: small and medium size enterprise, U: university, RI: research institute

*Participation is planned in Aug. 2006, meanwhile tasks are performed by ETH Zürich

EU PROJECT RESOLUTION - Reconfigurable Systems for Mobile Local Communication and Positioning

365

4.2 Interactive Guiding

Real-time based active mapping, e.g. for advanced

sightseeing, in museums, shopping malls and

amusement parks are useful for guiding of

pedestrians. The positioning is marked in a PDA

based map and can be transferred to a server.

Location dependent actions can be applied to

increase the amusement and information quality.

The services can be combined with location-aware

billing, which decreases personnel costs and

improves the billing system.

5 FIRST RESULTS

The project has just started. However, first

experiments with the master/slave approach

employing synchronized frequency ramps according

to Section 2.3 have already been performed. A 1-D

positioning accuracy of 20 cm at a coverage range of

up to 20 m is demonstrated.

6 CONCLUSIONS

A brief presentation of the EU project

RESOLUTION has been given, which aims to

develop a localization system with 3D accuracy in

the centimeter range on basis of FMCW radar.

REFERENCES

F. Ellinger, Radio Frequency Integrated Circuits and

Technologies, Springer, to be published 2006.

R. J. James, “A history of radar“, IEE Review, Vol. 35,

No. 9, pp. 343-349, 1989.

M. Skolnik, Radar Handbook, McGraw-Hill, 1990.

M. Vossiek, L. Wiebking, P. Gulden, J. Wieghardt, C.

Hoffmann, P. Heide, “Wireless local positioning”,

IEEE Microwave Magazine, Vol. 4, No. 4, pp. 77-86,

Dec. 2003.

L. Wiebking, Entwicklung eines zentimetergenauen

mehrdimensionalen Nahbereichs-Navigations-

Systems, VDI Verlag, 2003.

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