Achieving 30 cm Autonomous Single Frequency GPS positioning

Transcription

1 Achieving 30 cm Autonomous Single Frequency GPS positioning Dr. Y. Zhang Nexteq Navigation Corporation 3535 Research Road NW Calgary, Alberta, Canada T2L 2K8 AGG

2 Outline Background Motivation and Goal Technical Innovations Single-frequency Products Single-frequency Product Performance What s Next? Conclusions 2

3 GPS Error Sources Background Satellite orbit and clock Troposphere and ionosphere Multi path, receiver clock, measurement noise Standard Autonomous GPS single receiver point positioning with broadcast ephemeris simple, convenient, global and low cost several meter accuracy: not adequate for precise applications 3

4 Differential GPS Background requires at least one base receiver station (standard RTK) or even a network of base receiver stations (network RTK) rover GPS receivers must be nearby a base station costs and complexity: labor, subscription fee, compatible hardware (tens of K) cm ~ dm accuracy 4

5 Background Recent Autonomous GPS Receiver Development single receiver point positioning based on PPP for improved accuracy (Omnistar, Navcom Starfire) dm accuracy with dual frequency receiver sub meter accuracy with single frequency receiver require long initialization/re initialization time requires subscription to precise orbit and clock correction service (10K receiver, 1 several K sub fee) 5

6 Background Today, available GPS receiver products offer: high accuracy simplicity and convenience low cost But not at the same time! 6

7 Our Goal To develop a new class of GPS receiver that is: Autonomous (Single Receiver Point Positioning) simple, convenient with rapid operation Accurate 30 cm positioning accuracy Cost effective no need for base receiver, additional hardware, subscription to corrections We call this a Precise Autonomous Receiver 7

8 Technical Innovations Nexteq has developed a technology that meets the requirements of the Precise Autonomous Receiver (Freedom technology) Nexteq Freedom technology is a collection of innovations that re examines the way how errors are handled in GPS and maximizes the use of available GPS information 8

9 Technical Innovations Nexteq Freedom technology does not rely on precise orbit and clock, publicly free SBAS corrections are enough Nexteq Freedom technology properly handles the ionosphere delay for single frequency measurements Nexteq Freedom technology employ advanced QC algorithm Nexteq Freedom technology implement zero convergence time 9

10 Nexteq PAS Products Nexteq has successfully developed single frequency GPS receivers that meet the Precise Autonomous Receiver requirements (PAS) PAS110 Series PAS120 Series PAS110 Enclosure (3K) PAS112 compact antenna (2.5K) PAS115 OEM Board(2K) PAS120 Enclosure (3.5K) Low cost convenient 10

11 PAS Product Performance Calgary Hor RMSE: m Hei RMSE: m Mean Hor Err: m Mean Hei Err: m Standard SBAS PAS110 PAS120 Hor RMSE: m Hei RMSE: m Mean Hor Err: m Mean Hei Err: m Hor RMSE: m Hei RMSE: m Mean Hor Err: m Mean Hei Err: m Static Positioning (Open Sky) 11

12 PAS Product Performance Calgary Standard SBAS Hor RMSE: m Mean Hor Err: m PAS110 PAS120 Hor RMSE: m Mean Hor Err: m Hor RMSE: m Mean Hor Err: m Static Positioning (Under Forest Canopy) 12

13 PAS Product Performance Calgary Standard SBAS Hor RMSE: m Mean Hor Err: m PAS110 PAS120 Hor RMSE: m Mean Hor Err: m Hor RMSE: m Mean Hor Err: m Static Positioning (Near Buildings) 13

14 PAS Product Performance world wide North America Asia Europe 14

15 PAS Product Performance Dynamic 15

16 PAS Product Performance Dynamic std Lat (m) std Lon (m) std H (m) RMSE Lat (m) RMSE Lon (m) RMSE H (m) RMSE2D (m) Nexteq PAS Novatel ProPak dualfrequency Using post-processed double-differenced, dual-frequency positions as truth 16

17 What s Next? Freedom technology is not proprietary; it is able to improve the autonomous positioning accuracy of different types of GPS receivers 17

18 What s Next? precise autonomous dual frequency (PAD) GPS Hor RMSE: m Hei RMSE: m Mean Hor Err: m Mean Hei Err: m 18

19 PAS Product Performance Dynamic 19

20 What s Next? precise autonomous dual frequency (PAD) GPS Hor RMSE: m Hei RMSE: m 20

21 What s Next? PAD performance World wide North America Asia Europe 21

22 Conclusions Nexteq PAS GPS receiver products redefine the limits for autonomous single frequency GPS receivers and offers: Outstanding positioning performance of 30 cm Outstanding repeatability for harsh conditions Simple, convenient, cost effective Nexteq PAS GPS receiver products benefits all autonomous applications 22

23 Conclusions Nexteq PAD GPS receiver products redefine the limits for autonomous dual frequency GPS receivers and offers: Outstanding positioning performance of sub 20 cm Simple, convenient, cost effective No convergence time 23

24 Questions? 24