GLONASS Carrier-phase Inter-frequency Biases

Lambert WanningerGeodetic Institute, TU Dresden

Fakultät Forst-, Geo-, Hydrowissenschaften, Fachrichtung Geowissenschaften, Geodätisches Institut

IGS-Workshop on GNSS Biases, Bern, January 2012

IGS-Workshop on GNSS Biases, January 2012

Lambert Wanninger TU Dresden

2

GLONASS Inter-frequency Biases

Carrier-Phase Inter-frequency biases linearly dependent on frequency (= channel number k)

Single-difference observation equations GPS/GLONASS:

iba

GPSba

iba

iGPSba NtcR ,,0,

,,

iba

iGLOba

iGLOba

iba

iGLOba NhktcR ,,,0,

,,

GLObahc ,0 inter-frequency bias: [m]

IGS-Workshop on GNSS Biases, January 2012

Lambert Wanninger TU Dresden

3

GLONASS Amb. Fixing and Estimation of Bias

GLONASS observation data

(baseline, network)

a priori corrections of inter-frequency

biases

ambiguity fixing

parameterestimation

position, …,inter.-freq. biases

IGS-Workshop on GNSS Biases, January 2012

Lambert Wanninger TU Dresden

4

GLONASS Carrier-Phase Inter-frequency Biases

Receiver Manufacturer

a priori correctionsL1/L2 [cm]

Trimble –0.7

Ashtech, JPS, TPS 0.0

Leica 2.4

absolute level fixed

• few receivers• short/zero baselines

ION GNSS 2007

IGS-Workshop on GNSS Biases, January 2012

Lambert Wanninger TU Dresden

5

EuropeanGPS/GLONASS Receivers

IGS, EPN, Teria, + a fewmore = ~ 130stations

2 weeks in 2010:1570, 1599

IGS-Workshop on GNSS Biases, January 2012

Lambert Wanninger TU Dresden

6

Manufacturer Receiver Type Number of StationsGPS Week

1570GPS Week

1599Ashtech (old) Z-18 3 3

Ashtech (new) Pro Flex 500 CORS - 2

Javad TR-G3T DeltaTR-G3TH Delta

2-

11

JPS E GGDE GGDTEurocardLegacy

321

13

331

14

Leica GRX1200+GNSSGRX1200 GG PRO

743

1044

Novatel OEMV-3 3 3

Septentrio PolaRx3eTR - 1

TPS E GGDEurocardOdyssey EGB-1000NET-G3

81444

61444

Trimble NetR5NetR8

201

221

Sum 119 128

IGS-Workshop on GNSS Biases, January 2012

Lambert Wanninger TU Dresden

7

GLONASS Carrier-phase Inter-frequency Biases

Repeatability of daily estimates (RMS values)

“bad” stations:A – old AshtechsP – PAT0T – TORI

“good” stations

IGS-Workshop on GNSS Biases, January 2012

Lambert Wanninger TU Dresden

8

GLONASS Carrier-phase Inter-frequency Biases

L1/L2 results

IGS-Workshop on GNSS Biases, January 2012

Lambert Wanninger TU Dresden

9

GLONASS Carrier-phase Inter-frequency Biases

Results of ionosphere-free linear combination

IGS-Workshop on GNSS Biases, January 2012

Lambert Wanninger TU Dresden

10

GLONASS Carrier-phase Inter-frequency Biases

Station ONSA (actually baseline BUDP-ONSA),2009.0 – 2010.7

IGS-Workshop on GNSS Biases, January 2012

Lambert Wanninger TU Dresden

11

GLONASS Carrier-phase Inter-frequency Biases

Comparison week 1570 vs1599,iono.-free linearcombination

IGS-Workshop on GNSS Biases, January 2012

Lambert Wanninger TU Dresden

12

Jumps in L1time-series

probable cause:restart of receiver = internal recalibra-tion

GLONASS Carrier-phase Inter-frequency Biases

IGS-Workshop on GNSS Biases, January 2012

Lambert Wanninger TU Dresden

13

GLONASS Carrier-Phase Inter-frequency Biases

Receiver Manufacturer

a priori correctionsL1/L2 [cm]

Trimble –0.7

Ashtech (old), Javad, JPS, TPS 0.0

Ashtech (new) 0.4

Leica, Novatel 2.3

Septentrio 4.9

absolute level fixed

• ~ 130 receivers• baselines of up to 750 km

Journal of Geodesy, 2011/2012

IGS-Workshop on GNSS Biases, January 2012

Lambert Wanninger TU Dresden

14

GLONASS Code Delays

ionosphere-free linear combination (based on P1 and P2),

ESOC orbit and clock products,

2 weeks of observations (1627-1628)

frequency-dependence (but how to model?) receiver (type) individual rarely satellite individual

GLONASS FDMA code unusable forundifferenced amb. resolution(Melbourne-Wübbena linear combi.)

(ION GNSS 2011)