signal deformation proposal r. eric phelts, gabriel wong, todd walter, per enge stanford university...
TRANSCRIPT
Signal Deformation Proposal
R. Eric Phelts, Gabriel Wong, Todd Walter, Per Enge Stanford University
IWG 26February 5-7, 2014
2
Potential L1/L5 Tracking Constraints
• Current constraints allow early minus late (E-L) and double delta (DD) receivers– each have three regions describing receiver
filter bandwidth, group-delay variation across the passband, and correlator spacing
– SBAS GEOs have two regions• Propose removing double delta altogether
and shrinking allowed region– Also align SBAS & GPS tracking regions– BOC regions still being investigated
3
Current Allowed L1 Receiver Constraints
0.1
0.1
0.10.2
0.2
0.30.3
0.3
0.4
0.4
0.4
0.50.5
0.5
0.5
0.6
0.60.6
0.60.6
0.6
0.6
0.6
0.6
0.6
0.7
0.7
0.7
0.8
MAX: 0.884m; MIN: 0.0455m
Dou
ble-
Sid
ed A
ir B
W (
MH
z)
Air Correlator Spacing (chips)0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1
2
4
6
8
10
12
14
16
18
20
22
24Nominal SD Range Error Contours for WAAS Users
User Receiver Correlator Spacing (chips)
Use
r R
ecei
ver
Ban
dwid
th (
MH
z)
User Receiver Correlator Spacing (chips)
Use
r R
ecei
ver
Ban
dwid
th (
MH
z)New Reference
Current Reference Current Reference
New Reference
4
0 0.1 0.2 0.3 0.4 0.5 0.60
0.2
0.4
0.6
0.8
1
1.2
1.4
Time [sec]
Nor
mal
ized
Ste
p R
espo
nse
Blk-IIF-SVN62-L5 (5-chips) vs All SVN
All SVNBlk IIF-SVN62-L5-IBlk IIF-SVN62-L5-Q
Different code modulations have
similar structures at chip transitions.
Nominal Signal Deformations on L1 and L5
Slide Courtesy: Gabriel Wong
5
New Proposed Allowed DF Receiver Constraints (L1, L5)
0.1
0.1
0.10.2
0.2
0.30.3
0.3
0.4
0.4
0.4
0.50.5
0.5
0.5
0.6
0.60.6
0.60.6
0.6
0.6
0.6
0.6
0.6
0.7
0.7
0.7
0.8
MAX: 0.884m; MIN: 0.0455m
Dou
ble-
Sid
ed A
ir B
W (
MH
z)
Air Correlator Spacing (chips)0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1
2
4
6
8
10
12
14
16
18
20
22
24Nominal SD Range Error Contours for WAAS Users
User Receiver Correlator Spacing (chips)
Use
r R
ecei
ver
Ban
dwid
th (
MH
z)
User Receiver Correlator Spacing (chips)
Use
r R
ecei
ver
Ban
dwid
th (
MH
z)
L5L1
6
Proposal for BPSK Signals
• Only allow early minus late• L1 C/A
– Bandwidth between 12 and 24 MHz– Correlator spacing between 0.08 and 0.12– Group delay < 150 nsec (including antenna)
• L5/E5A– Bandwidth = tight region around 24 MHz– Correlator spacing = tight region around 1 chip
• Exact region TBD
– Group delay < 150 nsec (including antenna)
7
Proposal for SBAS Satellites
• Wide bandwidth SBAS satellites shall be treated identically to the BPSK requirements for GPS
• Narrow bandwidth SBAS satellites require one of the following actions:– Narrow bandwidth SBAS satellites not allowed– Bandwidth is indicated in message
• Tracked differently, may not be used for vertical
– Still tracked with narrow correlator, but UDRE indicates it cannot be used for vertical
8
Example: Digital Signal Deformation Fault on
CBOC(1,1) or TMBOC(1,1)
-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1-0.5
0
0.5
1
Code Offset (chips)
Some modernized code correlation peaks are relatively complex
9
Proposal for BOC Signals
• EUROCAE WG-62 proposed not using BOC(6,1) component– Agree to only track BOC(1,1)
• Same filter region as for L1 BPSK– Bandwidth between 16 and 24 MHz– Group delay < 150 nsec (including antenna)– Correlator spacing still under evaluation
• Early minus late only
10
Backup Slides
11
0.1
0.1
0.10.2
0.2
0.30.3
0.3
0.4
0.4
0.4
0.50.5
0.5
0.5
0.6
0.60.6
0.60.6
0.6
0.6
0.6
0.6
0.6
0.7
0.7
0.7
0.8
MAX: 0.884m; MIN: 0.0455m
Dou
ble-
Sid
ed A
ir B
W (
MH
z)
Air Correlator Spacing (chips)0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1
2
4
6
8
10
12
14
16
18
20
22
24
User Receiver Correlator Spacing (chips)
Use
r R
ecei
ver
Ban
dwid
th (
MH
z)
Propose removal
Nominal L1 SD Range Errors for Allowed User Receiver Configurations
L5 Nominal Deformation Errors (Updated)
0.02
0.02
0.02
0.02
0.02
0.04
0.04
0.040.04
0.04
0.040.04
0.06
0.06
0.060.06
0.06
0.060.06
0.08
0.08
0.080.08
0.08
0.1
0.1
0.10.1
0.12
0.12
0.12
0.14
0.14
0.14
0.16
0.16
0.18
0.2
MAX: 0.209m; MIN: 0.0095m
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.112
14
16
18
20
22
24
Correlator Spacing (chips)
Ban
dwid
th (
MH
z)