Citation: Yoon, Y.-M.; Lee, B.-S.;
Heo, M.-B. Multiple Cycle Slip
Detection Algorithm for a Single
Frequency Receiver. Sensors 2022, 22,
2525. https://doi.org/
10.3390/s22072525
Academic Editors: Kamil Krasuski
and Damian Wierzbicki
Received: 16 February 2022
Accepted: 23 March 2022
Published: 25 March 2022
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Article
Multiple Cycle Slip Detection Algorithm for a Single
Frequency Receiver
Young-Min Yoon
1,
*, Byung-Seok Lee
2
and Moon-Beom Heo
3
1
Korea Aerospace Research Institute, University of Science and Technology, Daejeon 34133, Korea
2
SBAS Program Office, Korea Aerospace Research Institute, Daejeon 34133, Korea; bslee@kari.re.kr
3
GNSS R&D Division, Korea Aerospace Research Institute, Daejeon 34133, Korea; hmb@kari.re.kr
* Correspondence: youngminyn@ust.ac.kr
Abstract:
A satellite navigation system makes it simple to find and navigate to a specific position.
Although a carrier measurement is required to establish a precise position due to the characteristics
of the carrier observation, it is difficult to determine a robust position in a poor signal reception
environment such as urban areas. Various studies are being carried out to overcome this problem,
with cycle slips being the most important factor. With only a single frequency, it is very challenging
to detect cycle slips in multiple satellite channels at the same time. A geometry-based technique
is proposed in this study as a technical solution for detecting simultaneous cycle slips for multiple
channels utilizing only a single-frequency receiver. The method could detect a half-wavelength size
of cycle slip for each channel through the geometry information.
Keywords: cycle slip; GPS; cross-ratio
1. Introduction
GPS signal carrier phase measurements can be used to obtain high-precision posi-
tioning and navigation solutions. Measurements of the carrier phase, on the other hand,
require the resolution of integer ambiguities. As long as the GPS receiver remains locked
to the satellite signal, it can keep track of an integer number of cycles. In practice, several
distracting variables may temporarily disrupt the GPS signal, resulting in a cycle slip (CS)
in the observed carrier phase. Signal interference from obstacles, a low signal intensity,
and receiver signal processing failure are all causes of CSs. If cycle slips occur, either the
ambiguities must be resolved, or the cycle slips must be repaired in order to resume the
accurate positioning and navigation procedure.
To avoid the delays and computational complexity associated with integer ambiguity
resolution, CSs should be detected and repaired. In fact, detecting CSs from carrier phase
measurements is challenging because it requires more information such as knowing the
position or calculating a precise positioning beforehand. Several studies have proposed
a combination of various instruments or methods for detecting and reducing CSs, but
there are limitations in adverse conditions such as urban surroundings. Carrier phase
measurements provide a precise position, but they necessitate the use of a dual-frequency
receiver. Furthermore, in some unusual simultaneous cycle slip combinations on L1 and
L2, the residual term in this combination may not provide any information about which
phase the cycle slip occurred in, or it may completely miss the detection of the
slip [1–8].
Although the time difference method removes ambiguous integers, it is only suitable
for static positioning applications [
2
,
9
–
16
]. Combinations of code phase measurements
are straightforward to implement, but noisy; thus, they are only used to detect large
cycle slips [
13
,
17
–
20
]. Cycle slips are unaffected by Doppler integration techniques, but
measurement error is caused by the receiver’s oscillator clock variance. High receiver
dynamics also have a significant impact on them [2,9,19,21–25]. The receiver autonomous
integrity monitoring (RAIM) methodology used in aviation is an example of a consistency
Sensors 2022, 22, 2525. https://doi.org/10.3390/s22072525 https://www.mdpi.com/journal/sensors
