Wireless networks based on highaltitude platforms for the provision of integrated navigationcommunic

1
Wireless networks based on high-altitude
platforms for the provision of integrated
navigation/communication services

• Avagnina, D. Dovis, F. Ghiglione, A.
  Mulassano, P.
• IEEE Communications Magazine , Volume 40 Issue
  2 , Feb 2002 Page(s) 119 -125

Yu-Lun, Liao
2
Outline

• Introduction
• HAP Overview
• HAP for Communications
• HAP for Navigation
• Integrated Services
• Conclusions

3
Introduction

• High Altitude Platforms (HAPs)
• Unmanned aircraft
• At altitudes ranging between 15-30 km
• Play a role similar to artificial satellite
• Less expensive, more adaptable, and closer to the
  ground
• Can make them almost stationary
• Move-on-demand
• Take off and land when needed
• Applications
• Telecommunication, remote sensing, pollution
  monitoring, meteorological measurement,

4
HAPs Overview

• Airship or aerodynamic aircraft
• NASA ERAST program
• ERAST (Environment Research Aircraft and Sensor
  Technology)
• a HAP prototype named Helios
• a new altitude record 96,500ft
• A valid alternative to traditional terrestrial or
  satellite telephony

5
HAPs for Communications

• Integrate or substitute the terrestrial or
  satellite system
• Ex they can be rapidly deployed to provide
  immediate coverage in disaster area
• The safety and the flexibility
• HAPs requires the different layers of the
  communication link
• HAPs for GSM/GPRS and UMTS has been discussed

6
Developing hypotheses

• A BTS is placed on a HAP
• 17km high, 100kg and 800W power
• HAP keeps a circular course
• A free-space propagation model
• The Signal fluctuation is a flat-fading model
• The aerial BTS is used to provide services to the
  aerial macrocell

7
The Model (airborne BTS)

• Connected to the rest communication network
• Carry all the traffic
• Mobile stations plus additional control signal

8
GSM/GPRS with HAPs

• For a emergency situation
• Synchronization constraints
• 116 us transmission delay
• Aerial cell radius R35km
• Interference in a terrestrial and a HAP

9
UMTS with HAPs

• The ITU has endorsed various frequency rages for
  HAP applications
• Specific bands are allocated to 3G wireless
  communication systems
• 1885-1980 MHz,2010-2025 MHz, 2110-2170 MHz in
  regions 1 and 3, 1885-1980 MHz, 2110-2160 MHz in
  region 2

10
HAPs for Localization Navigation

• A privileged eye for the localization
• The large coverage region with respect to ground
  stations
• The reduced altitude with respect to satellites
• Allows them easily listen to users

11
Positioning

• Station-based
• HAP with DOA (direction of arrival)
• OTD (Observed timing difference) in cellular
  network
• E-OTD (E for enhanced) for GSM
• OTD of arrival (OTDOA) for UMTS
• GNSS-based
• GPS/NAVSTAR(US), GLONASS(RUS), Galileo(EU),
  MTSAS(JPN), ??(??)
• The accuracy is improved by support system,
  denoted as augmentation system (AS)

12
HAP-Based Augmentation

• An active role within a GNSS
• Using HAP to broadcast the corrections
• It can be considered as a terrestrial satellite
• which is always in view and always available to
  the user, within a certain area
• Called pseudo-satellite or pseudolite

13
Stratolite

• The system (ground station HAP) has been name
  stratolite (stratospheric pseudo-satellite)
• Highly relies on the capability to finely
  localize the platform
• Code phase DGPS yielded to a localization
  accuracy at meter level in platform position

14
GPS without and with the stratolite

• GDOP the geometrical dilution of precision
• The lower one is better

15
Integrated Services

• Aerial BTS send the GNSS support information by
  means of the communication link
• It provides an additional ranging signal
• A hybrid terminal is used

16
HAP/User Standpoint

• HAP
• Users positions are very useful
• User
• Positioning accuracy
• The cheaper enhanced solutions about infomobility
  applications
• Ex air/marine/land transports
• The more on-demand services

17
Conclusions

• The constrains of positioning techniques
• A hybrid method HAP
• HAPs provide the better performance