Adaptive GNSS Positioning Method Capable of Adjusting to Ionospheric Delay

• US 20180188378A1
• Filed: 08/15/2016
• Published: 07/05/2018
• Est. Priority Date: 08/15/2016
• Status: Active Application

• Current Assignee: Topcon Positioning Systems Incorporated (Topcon Corporation)
• Original Assignee: Topcon Positioning Systems, LLC
• Granted Patent: US 10,288,743 B2
• Time in Patent Office: Days
• CPC Class Codes: G01S 19/40 Correcting position, velocity or attitude
• CPC Class Codes: G01S 19/43 using carrier phase measurements, e.g. kinematic positioning; using long or short baseline interferometry

Abstract

A plurality of GNSS satellite signals feeds the signal processing engine operating in certain processing mode including carrier phase smoothed pseudorange positioning, precise point positioning (PPP), pseudorange differential (DGNSS), and carrier phase differential (RTK). The processing engine calculates two estimates of the ionosphere delay for each satellite: the filtered delay and the instant delay. Comparison of them allows to detect turbulent variation of the ionosphere and adjust parameters of two-parametric dynamic mode which improves positioning precision.

Claims

1. A satellite navigation positioning method, comprising:

receiving n navigation signals from K navigation satellites, wherein the n navigation signals are on at least two different carrier frequencies, and wherein n is at least 8 and K is at least 4;

on a processor of a navigation receiver, calculating current coordinates based on the n navigation signals;

executing an adaptive positioning algorithm for adjusting parameter z representing a time constant of a rate of variation of ionospheric delay, and a scale factors, which ranges from 1 to 10 and which relates to a baseline length and solar activity; and

correcting the calculated current coordinates based on the adaptive positioning algorithm.

2. The method of claim 1, further comprising calculating a filtered estimate i(t+1) using parameters τ

_i and s;

3. The method of claim 2, further comprising calculating an instant estimate i*(t+1) calculated based on instant carrier phase measurements and instant carrier phase ambiguity estimate.

4. The method of claim 2, further comprising calculating a correlation coefficient

5. The method of claim 3, further comprising reducing τ

_i if the correlation coefficient is less than a threshold value T_l.

6. The method of claim 3, further comprising increasing τ

_i if the correlation coefficient is greater than a threshold value T_l.

7. The method of claim 1, further comprising increasing s if

∥

i*(t+1)∥

>

∥

(t+1)∥

is true for several sequential time instances.

8. The method of claim 1, further comprising decreasing s if

∥

i*(t+1)∥

<

∥

i(t+1)∥

is true for several sequential time instances.