A performance improvement method for low-cost land vehicle GPS/MEMS-INS attitude determination.

Honglei Qin,Keck Ling,Li Cong,Ercui Li,Rui Xue

doi:10.3390/s150305722

Honglei Qin, Keck Ling + Show 3 more

Open Access

https://doi.org/10.3390/s150305722

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Abstract

Global positioning system (GPS) technology is well suited for attitude determination. However, in land vehicle application, low-cost single frequency GPS receivers which have low measurement quality are often used, and external factors such as multipath and low satellite visibility in the densely built-up urban environment further degrade the quality of the GPS measurements. Due to the low-quality receivers used and the challenging urban environment, the success rate of the single epoch ambiguity resolution for dynamic attitude determination is usually quite low. In this paper, a micro-electro-mechanical system (MEMS)—inertial navigation system (INS)-aided ambiguity resolution method is proposed to improve the GPS attitude determination performance, which is particularly suitable for land vehicle attitude determination. First, the INS calculated baseline vector is augmented with the GPS carrier phase and code measurements. This improves the ambiguity dilution of precision (ADOP), resulting in better quality of the unconstrained float solution. Second, the undesirable float solutions caused by large measurement errors are further filtered and replaced using the INS-aided ambiguity function method (AFM). The fixed solutions are then obtained by the constrained least squares ambiguity decorrelation (CLAMBDA) algorithm. Finally, the GPS/MEMS-INS integration is realized by the use of a Kalman filter. Theoretical analysis of the ADOP is given and experimental results demonstrate that our proposed method can significantly improve the quality of the float ambiguity solution, leading to high success rate and better accuracy of attitude determination.

Highlights

In low-cost land vehicle navigation applications, are accurate position and velocity information required, but the navigation system needs to provide accurate attitude [1,2,3,4]
Field tests in an urban area were conducted to verify the performance of the Global positioning system (GPS)/micro-electro-mechanical system (MEMS)-inertial navigation system (INS)
It consists of a MEMS-INS and the GPS attitude determination system developed by our research group

Summary

Introduction

In low-cost land vehicle navigation applications, are accurate position and velocity information required, but the navigation system needs to provide accurate attitude [1,2,3,4]. The CLAMBDA method [22,23] is proposed for attitude determination by integrating the nonlinear baseline constraint into the ambiguity objective function It further improves the success rate of attitude determination, especially for single frequency single epoch cases [24,25], but the CLAMBDA method is challenged for the single frequency single epoch case in low-cost land vehicle applications, since the unconstrained float solution is usually of very low quality due to the poor quality GPS measurements, especially when the GPS signal is blocked or contaminated by multipath signals in urban areas, which results in decreased success rates [21,26].

GPS Attitude Determination with the CLAMBDA

Improved Attitude Determination Method for Single Frequency and Single Epoch

I 0 a

Quality Assessment of Float Solution

Float Solution with INS-Aided AFM

The Implementation of the Proposed Method

I F119 9

Measurement Equations of the Integrated Filter

G V

Experiment Test Results

Test Settings

Test Results