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El‑Sheimy and Li Satell Navig (2021) 2:7 Page 11 of 23

Table 9 Principle, advantages, and disadvantages of PLAN sensors
Sensor Principle Advantage Disadvantage
HD map Use detailed road and infrastructure data High accuracy High requirement on update and accuracy
for precise localization and environment High resolution High accuracy requirement
perception Rich environment and infrastructure layers Costly in generation and maintenance
LiDAR Use infrared light waves to measure dis‑ High ranging accuracy High cost
tances and generate point clouds Dense point cloud Large size
Being used in consumer devices The problem in the life span
Dependency on the signifcance of features
Camera Collect and analyze images for localization Low cost Sensitivity to illumination and weather
and perception purposes Dense point clouds with colors Dependency on the signifcance of features
Passive sensing
RADAR Use radio waves for ranging and object Low cost Low measurement density
detection Accurate ranging Cannot detect markers
Small size, being used in cars
WiFi/BLE Use local communication signals for Existing infrastructure Low accuracy by RSS
localization Supported by consumer devices High power consumption in WiFi
Problems inherent to wireless signals (e.g.,
multipath, NLoS, and variation)
5G Use next‑generation cellular signal for Existing infrastructure Low accuracy by RSS
localization Supported by consumer devices Problems inherent to wireless signals
New features, such as miniaturized base Current base station density is low
station and mmWave MIMO
LPWAN Use IoT signals for localization Supported by IoT devices Low accuracy by RSS
Low cost Problems inherent to wireless signals
Low power consumption
Long range
INS Measure angular rates and linear specifc Self‑contained Relative navigation solution
forces to derive motion states Robust in the short term High cost for high‑end sensors
Of‑the‑shelf sensors in consumer devices Signifcant errors for low‑cost sensors
Full motion states
GNSS Localize device using satellite trilateration Global absolute position fxing Signal degradation in urban and indoor
High precision when converged (with regions
RTK/PPP) Prone to jam and spoof
Supported by consumer devices Relatively weak in attitude determination
UWB/ultrasonic Precise localization through precise rang‑ High‑precision ranging Require extra infrastructure
ing Cost is reducing, being used in consumer Problems inherent to wireless signals
devices

troposphere errors, wall efects, and human body efects). Te research work (Wang and Ho 2015) provides a theo-
In addition, it is necessary to reduce the infuence of end- retical derivation and performance analysis of the trian-
device factors (e.g., device diversity). gulation method.
Te research work (Petovello 2003) describes the Angle-based PLAN solution can typically provide high
range-based PLAN algorithm and its quality control. accuracy (e.g., decimeter-level) in a small area (e.g., 30 m
Meanwhile, the research work (Langley 1999) proposes by 30 m) (Quuppa 2020). Te challenge is that AoA sys-
an index (i.e., the dilution of precision) for the evaluation tems require specifc hardware (e.g., an array of antennae
of signal geometry. A strong geometry is a necessary con- and a phase-detection mechanism) (Badawy et al. 2014),
dition, instead of a necessary and sufcient condition, for which is complex and costly. Tere are low-cost angle-
accurate range-based localization because there are other based solutions such as that use RSS measurements from
error sources, such as the stochastic ones. multiple directional antennae (Li et al. 2020b). However,
for wide-area applications, both the angle measurement
Angle‑based methods and PLAN accuracy are signifcantly degraded. Te Blue-
Triangulation, a typical AoA based PLAN method, com- tooth 5.1 (Bluetooth 2019) has added the direction meas-
putes the device location by using the direction meas- urement, which may change the angle-based PLAN.
urements to multiple base stations that have known
locations (Bai et al. 2008). When direction measurement Angle‑and‑range‑based methods
uncertainty is considered, the direction measurement Multiangulateration, a typical angle-and-range-based
from two base stations will intersect to a quadrilateral. PLAN method, calculate the device location by using its