Enabling high precision positioning on Android devices The French Institute of Science and Technology for Transport, Development and Networks Antoine GRENIER Céline RAGOIN Valérie RENAUDIN GNSS measurements Taskforce Workshop Prague, June 26th 2019 1
15
Embed
The French Institute of Science and Technology for Transport ... · positioning on Android devices The French Institute of Science and Technology for Transport, Development and Networks
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Enabling high precision positioning on Android devices
The French Institute of Science and Technology for Transport,
Development and Networks
Antoine GRENIERCéline RAGOINValérie RENAUDIN
GNSS measurements Taskforce WorkshopPrague, June 26th 2019
● Signal combination○ Allow ionospheric correction (“Iono-free” combination)○ Require multiple frequency acquisition
■ Xiaomi Mi8 with L1 and L5 capacities
2
www.ifsttar.fr26/06/2019 3Credits @ Roberto Lee Cortes
Environment c
onstraints
www.ifsttar.fr26/06/2019
Environment constraints
● Only 12 GPS satellites with L5 signals○ 4-5 available in open sky ○ Less in an urban canyon -> PPP system unsolvable or non redundant○ Use multiple constellations (GALILEO, BEIDOU, ...)
● Problem○ GALILEO navigation message not available on Xiaomi Mi8
[1] Tomasz Hadas and Jaroslaw Bosy. “IGS RTS precise orbits and clocks verifcation and quality degradation over time”. In: (2014).[2] RTCM. RTCM 10403.3, Differential GNSS (Global Navigation Satellite Systems) Services. Radio Technical Commission For Maritime Services. 2016.
www.ifsttar.fr26/06/2019
Raw measurements
● Validity○ Pseudorange and phase need to be independent from each other
■ Ex: Low cost receivers
12
Source: Zhu Ni, GEOLOC/IFSTTAR
www.ifsttar.fr26/06/2019
Raw measurements
● Validity - Xiaomi Mi8 results
13
www.ifsttar.fr26/06/2019
Raw measurements
● Quality○ Precise phase measurements○ Fewest cycle slip possible
■ Ambiguity estimation and resolution
14
www.ifsttar.fr26/06/2019
Applying corrections
● Applied on coordinates computed from broadcast ephemeris
● Broadcast ephemeris can be retrieved from streams
15
○ IoD (Issue of Data) id of broadcast and corrections need to be similar
Source: Schmitz, 2012 [2]For details see references [2, 3]
[2] Martin Schmitz. RTCM State Space Representation Messages, Status and Plans. Geo++ GmbH, 2012.[3] RTCM. RTCM 10403.3, Differential GNSS (Global Navigation Satellite Systems) Services. Radio Technical Commission For Maritime Services. 2016.