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Table 1 Adopted models and strategies

From: GNSS rapid precise point positioning enhanced by low Earth orbit satellites

Items

Model and strategies

PPP float solution

PPP-AR solution

PPP-RTK solution

Frequency selection

GPS/LEO: L1/L2;

BDS-2/BDS-3: B1I/B3I;

Galileo: E1/E5a; GLONASS: G1/G2

GPS/LEO: L1/L2;

BDS-31: B1I/B3I;

Galileo: E1/E5a;

GPS/LEO: L1/L2;

BDS-3: B1I/B3I;

Galileo: E1/E5a

Sampling interval

30 s

5 s

5 s

Estimator

Kalman filtering

Kalman filtering

Kalman filtering

Cut-off elevation angle

7°

Float: 7°

Fix: 10°

Float: 7°

Fix: 10°

Phase ambiguities

Constant estimation

Constant estimation and ambiguities fixed with WL2/NL3

Server: Constant estimation and ambiguities fixed with WL/NL

User: Constant estimation and ambiguities fixed with WL + N1/N24

Station coordinates

Estimated as constants in static mode

Estimated as constants in static mode

Server: Constraints, estimated as constants in static mode User: Estimated in dynamic mode

Observations

IF observations of carrier phase and code observation

IF observations of carrier phase and code observation

Server: IF observations of carrier phase and code observation User: UCUD phase and code observation

Ionospheric delay

Eliminated by IF observations

Eliminated by IF observations

Server: Eliminated by IF observations User: Constraint, Estimated by random walk

Tropospheric wet delay

Estimated by random walk NMF mapping function

Estimated by random walk NMF mapping function

(1) Server: Estimated by random walk with NMF5 mapping function(2) User: Constraint, Estimated by random walk with NMF mapping function

Satellite orbit and clock

Precise products

  

Satellite and receiver antenna phase center, Tropospheric dry delay, and other modelable errors

Model correction

  
  1. 1BDS-3, the third-generation BDS; 2WL, Wide-Lane; 3NL, Narrow-Lane; 4N1/N2, ambiguity at frequency 1/2; 5NMF, Neill Mapping Function