Ch 40. Navigation with Terrestrial Digital Broadcasting Signals

Chapter Overview:

This chapter describes how to use terrestrial digital television (DTV) signals for position, navigation, and timing (PNT). DTV signals have high power and large coverage. With transmitters fixed on the ground, DTV signals experience less Doppler frequency shift than GNSS signals from orbiting satellites. In the VHF/UHF bands, they are less affected by changes in relatively short radio propagation path. Finally, the DTV signal bandwidth is 6 ~ 8 MHz, wider than that of GPS C/A-code and comparable to GPS P(Y)-code, leading to more accurate timing/ranging and better positioning.

However, practical use of DTV signals for PNT faces several challenges. There is no explicit time of transmit and location of transmitter information modulated on broadcast signals as GNSS does. Most of transmitters have relatively low-quality clocks, not synchronized. The number of DTV transmitters in a region is limited and the resulting geometric dilution of precision (DOP) may be poor. Besides, the PNT solution is 2D rather than 3D. More critically, multipath at reception is severe, particularly in urban environments, with rapid fading and non-line-of-sight (NLOS) signals. The last, but not least, issue is signal integrity and authenticity by the very nature of being a signal of opportunity.

This chapter provides the background information and technical fundamentals to address these issues. After a discussion of general methods, representative DTV signals are presented, which include DVB-T (Digital Video Broadcasting – Terrestrial), ISDB-T (Integrated Services Digital Broadcasting – Terrestrial), DTMB (Digital Terrestrial Multimedia Broadcast), and ATSC-8VSB (American Television Standard Committee 8-ary Vestigial Sideband Modulation), retro-dubbed as ATSC 1.0, and the upcoming ATSC 3.0. Software receivers for ATSC-8VSB and OFDM-based DVB-T are detailed. Conversion of acquired DTV signals into pseudorange measurements is formulated with test data illustrations and examples of standalone DTV positioning presented.

From this page you can:

• Download hi-res images, for use with attribution.

• Read or contribute to errata.

• Give feedback.

Table of Contents:

40 Navigation with Terrestrial Digital Broadcasting Signals

40.1 PNT Mechanisms with Broadcasting Signals

40.2 Representative Terrestrial Digital Broadcasting Signals

40.2.1 Acquisition and Tracking of ATSC-8VSB Signals for Timing and Ranging

40.2.2 Acquisition and Tracking of DVB-T Signals for Timing and Ranging

40.2.3 ISDB-T Signals for Timing and Ranging

40.2.4 DTMB Signals for Timing and Ranging

40.2.5 Next-Gen ATSC 3.0 Signals for Timing and Ranging

40.3 Pseudorange Measurements from Broadcasting Signals

Mobile Test 1: Slow and Fast Fading

Mobile Test 2: Clock Errors and Calibration

Mobile Test 3: Delay Spread and NLOS

40.4 Practical Issues and Search for Solutions

40.4.1 Analysis of Geometry Effect on Positioning Performance

40.4.2 Radio Dead Reckoning with Mixed SOOP

40.4.3 Toward Practical Robust Operations

References