L2C Signal Research Articles

Comparative Hypothesis Testing of Auroral Ionospheric Layer Causing Global Navigation Satellite System Scintillation

AbstractAs Global Navigation Satellite System electromagnetic waves pass through the ionosphere, especially in auroral zones, ionospheric irregularities cause the waves to scintillate. Identification of the ionosphere scattering layer is an important factor in understanding the cause of scintillation. This work implements two techniques to determine whether signal scattering for Global Positioning System L1 and L2C signals might be in the E‐ or F‐layer. The first technique used is an updated process of Sreenivash et al. (2020, https://doi.org/10.1029/2018RS006779), in which the Poker Flat Incoherent Scatter Radar (PFISR) maximum electron densities and their uncertainties hypothesize the layer in which scattering has occurred. The density‐based method predicts a majority of F‐region scintillation events for 2014, with a majority of E‐region events found for 2015 to 2019. The second technique consists of using the ratio of the 630 (red) to the 428 nm (blue) intensity in optical all‐sky images (ASIs) to hypothesize the scattering layer with ASI. The decision threshold is set to 1.35 based on the GLobal airglOW model. From 2014 to 2018 174 events have both PFISR data and ASIs with clear viewing conditions and alignment to within 25° of magnetic zenith. There is an agreement between the two methods for 128 (74%) events.

Coherent Combination of GPS III L1 C/A and L1C Signals for GNSS Reflectometry

Coherent Combination of GPS III L1 C/A and L1C Signals for GNSS Reflectometry

Binary Offset Carrier (BOC) and Binary Phase Shift Keying (BPSK) Modulation in Indoor Drones GNSS Recievers using Multipath Error Envelope MEE Technique

The applications of unmanned aerial vehicles (UAVs) have greatly eased the lives of human being. Due to the mass commerial production of UAVs (or Drones) and the support of the ongoing scientific research, it can now be used in disaster monitoring, surviellance, fire conrolling and many outdoor usages. However, the indoor applications have stricter requirements for the autonomous positioning capability of UAVs, requiring its positioning accuracy to be within the narrower areas and aisles. The Global Navigation Satellite System (GNSS) is currently the only guidance and autorecovery method that can be applied directly and consistently to UAV positioning. The current GPS L1C and/or Galileo E1 open services signals are being widely used for this purpose. Moreover, the Binary Offset Carrier (BOC) techniques have been recently adopted in Galileo and GPS BIII as one of the efficient mitigation methods to decrease the interference/multipath delays and to increase both the Position Accuracy and the immunity of GNSS interferences. This research aims to present a software method of assessing the improvements of the Accuracy, and yet the Availability, by producing the MEE for BOC technique. The used methodology is analyzing the theoretical equations behind the interfernece multipath error envelopes in both BPSK and the new BOC signals. The Results show a higher performance of BOC GNSS Recievers over BPSK ones, and less delay.

Data + pilot biases in modern GNSS signals

While traditional GNSS signals are always modulated with navigation data, various modern signals provide a distinct pilot channel without data modulation to support long coherent integration times. Intra-signal biases between the data and pilot components of such signals are evaluated for satellites of the GPS, Galileo, BeiDou-3, and QZSS constellations using measurements from a dedicated set of receivers. Peak values of about 2 ns are obtained for the GPS L5 signal, while slightly smaller values of up to 1 ns apply for the B1C and B2a signals of BeiDou-3 as well as the QZSS L1C signal. For Galileo E1 and E5a/b, data + pilot biases are confined to less than 0.1–0.3 ns, which is typically less than other pseudorange errors for these signals. Fully negligible values of < 0.05 ns are obtained for the L1C and L2C signals of GPS as well as the L2C signal of QZSS in accord with expectations for time-multiplexed or interlaced modulations. To support consistent processing of multi-GNSS data in heterogeneous networks, biases between combined data + pilot tracking and pilot-only tracking are derived in a dedicated zero-baseline receiver test bed. The analysis confirms the general understanding that biases between combined and pilot-only pseudoranges amount to a fixed fraction of the corresponding data + pilot biases. This fraction depends on the power sharing of the data and pilot component in the respective signals and amounts to 50% in most cases. The results of this study are expected to remove the prevailing problem of two distinct receiver groups in the generation of satellite clock and bias products by the International GNSS Service and to enable a rigorous and consistent use of these products by multi-GNSS users.

Carrier Characteristic Bias Estimation between GNSS Signals and Its Calibration in High-Precision Joint Positioning

A distinctive feature of modern Global Navigation Satellite System (GNSS) signals is that they transmit multiple signal components at the same carrier frequencies. The idea of joints across the signal channels from the same carrier frequency and even across different frequencies has been presented in many studies for tracking purposes. Carrier joint tracking is required on the premise that the frequency and phase relationship between signals are nominal values, and the bias of carrier characteristics between signals is drowned in noise as the signal reaches the ground, which requires high-gain receiving equipment to restore the original signal. The space signal-quality monitoring and evaluation system built by the National Timing Center of the Chinese Academy of Sciences is based on a 40 m dish antenna, which can automatically track a single satellite and achieve a high-fidelity reception of navigation signals to a certain extent, realizing fine signal quality monitoring (SQM) of GNSS satellites. Based on this platform, we discuss four types of time distributions of the combined signals among different signal components and provide a method to estimate the carrier characteristic bias between GNSS signals. We derived the correction method of carrier characteristic bias in the joint reception by the joint tracking mathematical model. Under the conditions of narrow correlation and unobstructed case, the carrier characteristic deviation does not vary significantly with the correlator interval and the satellite elevation angle. Based on the results of stability analysis, it is recommended that the receivers should update the carrier frequency bias correction number of the intra-frequency signal and carrier phase bias correction number of the intra-frequency signal monthly. The carrier phase deviation correction number of the inter-frequency signal is performed daily. The measured data from satellites show that the phase accumulation error of the joint tracking carrier loop can be eliminated to achieve long-term stable tracking after frequency bias correction. After the carrier phase bias correction, the joint positioning accuracy of the B2a and B2b signals was improved by 0.81%, and those of the B1C, L1C, E1C, and B2a signals were improved by 0.35%, 0.04%, 0.20%, and 0.11%, respectively. The positioning accuracy improvement effect of inter-frequency signals was greater than that of intra-frequency signals after carrier phase correction.

Feasibility Analysis of GPS L2C Signals for SSV Receivers on SBAS GEO Satellites

This paper analyzes the feasibility of Global Positioning System (GPS) L2C signals for use with the space service volume (SSV) receiver on satellite-based augmentation system (SBAS) geostationary orbit (GEO) satellites equipped with L1 and L5 band signal transmitters. Augmentation signals transmitted at L1 and L5 bands from SBAS GEO satellites may interfere with the same bands of SSV GPS-receiving antennas. Therefore, the use of L1 and L5 band signals for the GPS SSV receiver on SBAS GEO satellites is prohibited, and the GPS L2C signal is selected. Unlike ground systems, the various constraints of space exploration in GEO should be considered. Therefore, signal feasibility analysis is essential before considering the use of new global navigation satellite system (GNSS) signals in GEO. This paper presents satellite visibility, dilution of precision, and navigation solution error when the GPS L2C signal is used in GEO satellites through numerical simulation.

Verification and Validation of the COSMIC-2 Excess Phase and Bending Angle Algorithms for Data Quality Assurance at STAR

In recent years, Global Navigation Satellite System (GNSS) radio occultation (RO) has become a critical observation system for global operational numerical weather prediction. Constellation Observing System for Meteorology, Ionosphere, Climate (COSMIC) 2 (COSMIC-2) has been a backbone RO mission for NOAA. NOAA also began to purchase RO data from commercial sources in 2020. To ensure the consistent quality of RO data from different sources, NOAA Center for Satellite Applications and Research (STAR) has developed capabilities to process all available RO data from different missions. This paper describes the STAR RO processing systems which convert the pseudo-range and carrier phase observations to excess phases and bending angles (BAs). We compared our COSMIC-2 data products with those processed by the University Corporation for Atmospheric Research (UCAR) COSMIC Data Analysis and Archive Center (CDAAC). We processed more than twelve thousand COSMIC-2 occultation profiles. Our results show that the excess phase difference between UCAR and STAR is within a few centimeters at high altitudes, although the difference increases towards the lower atmosphere. The BA profiles derived from the excess phase are consistent with UCAR. The mean relative BA differences at impact height from 10 to 30 km are less than 0.1% for GLObal NAvigation Satellite System (GLONASS) L2C signals and Global Positioning System (GPS) L2C and L2P signals. The standard deviations are 1.15%, 1.15%, and 1.32% for GLONASS L2C signal and for GPS L2C and L2P signals, respectively. The BA profiles agree with those derived from European Center for Medium-range Weather Forecast (ECMWF) reanalysis version 5 (ERA5). The Signal-to-Noise-Ratio (SNR) plays an essential role in the processing. The STAR BA profiles with higher L1 SNRs (L1 at 80 km) tend to yield more consistent results than those from UCAR, with a negligible difference and a smaller deviation than lower SNR profiles. Profiles with lower SNR values tend to show a more significant standard deviation towards the surface during the open-loop stage in the lower troposphere than those of higher SNR. We also found that the different COSMIC-2 clock solutions could contribute to the significant relative BA difference at high altitudes; however, it has little effect on the lower troposphere comparisons given larger BA values.

Experimental Analysis of GPS L2C Signal Quality under Various Observational Conditions

To appropriately handle the GPS L2C signal for the future development of positioning algorithms, this contribution has endeavoured to figure out its features by computing some quality measures of all the modernised satellites (i.e., twenty-three as of January 2022) and comparing them with those of the C/A and P2(Y) code. A series of quality analyses have been carried out to GPS measurements at twenty-four continuously operating reference stations (CORS) equipped with eight receiver models. In addition, experimental data acquired by a combination of high-end and cost-effective receivers have been intensively assessed to characterise the relative signal quality of the L2C to the legacy codes. The observational conditions considered in this study include different multipath environments and receiver dynamics. The results of the analyses, in general, indicate that the quality of the L2C-derived measurements is equivalent to the legacy civilian code (i.e., C/A) but superior to the encrypted military signal (P2(Y)). Hence, it is expected that the new civilian GPS signal enhances the positioning performance of dual-frequency measurements with both high-end and cost-effective receivers.

BDS/GNSS multipath reflectometry (BDS/GNSS-MR) based altimetry with new signals: Initial assessment and comparison

The BeiDou Navigation Satellite System with global coverage (BDS-3) was officially launched on July 31, 2020. In addition to the legacy B1I and B3I signals from the regional system (BDS-2), BDS-3 provides several new signals, i.e., B1C, B2a, B2b and B2a + b, with advanced technologies and global availability, which brings new opportunities for ground-based BDS multipath reflectometry (BDS-MR) altimetry. Previous studies focused on the MR altimetry performance of the legacy signals using signal-to-noise ratio (SNR) observations, but the new BDS signals have not been investigated. In this contribution, all types of BDS-3 SNR data collected from seven International GNSS Service (IGS) stations are analyzed signal by signal in terms of SNR quality and altimetry performance, while the legacy BDS B2I and Global Positioning System (GPS) L2C signals are also selected for comparison. Seven globally distributed IGS stations are first investigated for the quality of SNR observations, and then two optimally selected land stations are used to assess BDS-MR based altimetry performance, while a coastal station is used to assess BDS-MR for sea level retrieval performance. It is found that the quality of SNR observations varied site by site due to the differences in environment and equipment, but in general, the new signals except B1C show a higher level of SNR. Then, no detectable biases among each signal are found for land altimetry, while new signals could yield higher amplitude when performing spectral analysis. In coastal sea level altimetry, only two new signals B1C and B2a are available at the selected IGS station, and it is observed that the retrieval performance of BDS B2a is comparable to that of B2I, B3I and GPS L2C with root-mean-square errors (RMSEs) of about 21 cm, while that for B1I and B1C is slightly poorer with RMSEs of 29.68 cm and 26.66 cm respectively.

Performance assessment of GNSS-based real-time navigation for the Sentinel-6 spacecraft

The feasibility of precise real-time orbit determination of low earth orbit satellites using onboard GNSS observations is assessed using six months of flight data from the Sentinel-6A mission. Based on offline processing of dual-constellation pseudorange and carrier phase measurements as well as broadcast ephemerides in a sequential filter with a reduced dynamic force model, navigation solutions with a representative position error of 10 cm (3D RMS) are achieved. The overall performance is largely enabled by the superior quality of the Galileo broadcast ephemerides, which exhibits a two- to three-times smaller signal-in-space-range error than GPS and allows for geodetic-grade GNSS real-time orbit determination without a need for external correction services. Compared to GPS-only processing, a roughly two-times better navigation accuracy is achieved in a Galileo-only or mixed GPS/Galileo processing. On the other hand, GPS tracking offers a useful complement and additional robustness in view of a still incomplete Galileo constellation. Furthermore, it provides improved autonomy of the navigation process through the availability of earth orientation parameters in the new civil navigation message of the L2C signal. Overall, GNSS-based onboard orbit determination can now reach a similar performance as the DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) navigation system. It lends itself as a viable alternative for future remote sensing missions.

Area-Efficient Universal Code Generator for GPS L1C and BDS B1C Signals

Recently, multi-frequency multi-constellation receivers have been actively studied, which are single receivers that process multiple global navigation satellite system (GNSS) signals for high accuracy and reliability. However, in order for a single receiver to process multiple GNSS signals, it requires as many code generators as the number of supported GNSS signals, and this is one of the problems that must be solved in implementing an efficient multi-frequency multi-constellation receiver. This paper proposes an area-efficient universal code generator that can support both GPS L1C signals and BDS B1C signals. The proposed architecture alleviates the area problem by sharing common hardware in a time-multiplex mode without degrading the overall system performance. According to the result of the synthesis using the CMOS 65 nm process, the proposed universal code generator has an area reduced by 98%, 93%, and 60% compared to the previous memory-based universal code generator (MB UCG), the Legendre-generation universal code generator (LG UCG), and the Weil-generation universal code generator (WG UCG), respectively. Furthermore, the proposed generator is applicable to all Legendre sequence-based codes.

Performance Assessment of Real-Time Multiconstellation GNSS PPP Using a Low-Cost Dual-Frequency GNSS Module

Abstract The release of low-cost dual-frequency (DF) global navigation satellite system (GNSS) modules provides an opportunity for low-cost precise positioning to support autonomous vehicle applications. The new GNSS modules support the US global positioning system (GPS) L1C/L2C or L5 civilian signals, the Russian GNSS Globalnaya Navigazionnaya Sputnikovaya Sistema (GLONASS) L1/L2, Europe’s GNSS Galileo E1/E5b, and Chinese GNSS BeiDou B1/B2 signals. The availability of the DF measurements allows for removal of the ionospheric delay, enhancing the obtained positioning accuracy. Unfortunately, however, the L2C signals are only transmitted by modernized GPS satellites. This means that fewer GPS DF measurements are available. This, in turn, might affect the accuracy and the convergence of the GPS-only precise point positioning (PPP) solution. Multi-constellation GNSS PPP has the potential to improve the positioning accuracy and solution convergence due to the high redundancy of GNSS measurements. This paper aims to assess the performance of real-time quad-constellation GNSS PPP using the low-cost u-blox Z9D-F9P module. The assessment is carried out for both open-sky and challenging environment scenarios. Static, simulated-kinematic, and actual field-kinematic trials have been carried out to evaluate real-time PPP performance. Pre-saved real-time precise orbit and clock products from the Centre National d’Etudes Spatiales are used to simulate the real-time scenario. It is shown that the quad-constellation GNSS PPP using the low-cost u-blox Z9D-F9P module achieves decimeter-level positioning accuracy in both the static and simulated-kinematic modes. In addition, the PPP solution convergence is improved compared to the dual- and triple-constellation GNSS PPP counterparts. For the actual kinematic trial, decimeter-level horizontal positioning accuracy is achieved through the GPS + GLONASS + Galileo PPP compared with submeter-level positioning accuracy for the GPS + GLONASS and GPS + Galileo PPP counterparts. Additionally, submeter-level vertical positioning accuracy is achieved through the GPS + GLONASS + Galileo PPP compared with meter-level positioning accuracy for GPS + GLONASS and GPS + Galileo PPP counterparts.

A deep fading assessment of the modernized L2C and L5 signals for low-latitude regions

A deep fading assessment of the modernized L2C and L5 signals for low-latitude regions

On the Properties of and Ionospheric Conditions Associated With a Mid‐Latitude Scintillation Event Observed Over Southern United States

AbstractWhile low and high‐latitude ionospheric scintillation have been extensively reported, significantly less information is available about the properties of and conditions leading to mid‐latitude scintillations. Here, we report and discuss scintillation observations made in the Southern United States (UT Dallas, 32.99°N, 96.76°W, 43.2°N dip latitude) on June 1st, 2013. The measurements were made by a specialized dual‐frequency GPS‐based scintillation monitor which allowed us to determine main properties of this mid‐latitude scintillation event. Additionally, simultaneous airglow observations and ionospheric total electron content (TEC) maps provided insight on the conditions leading to observed scintillations. Moderate amplitude scintillations (S4&gt;∼0.4) occurred in both L1 and L2C signals, and severe (S4 &gt; ∼0.8) events occurred in L2C signals at low (&lt;30°) elevation angles. Phase scintillation accompanied amplitude fadings, with maximum σϕ values exceeding 0.5 radians in L2C. We also show that the observed phase scintillation magnitudes increased with amplitude scintillation severity. Decorrelation times were mostly between 0.25 and 1.25 s, with mean value around 0.65 s for both L1 and L2C. Frequency scaling of S4 matched fairly well the predictions of weak scattering theory but held for observations of moderate and strong amplitude scintillation as well. Scintillation occurred during the main phase of a modest magnetic storm that, nevertheless, prompted an extreme equatorward movement of the mid‐latitude trough and large background TEC enhancements over the US. Scintillations, however, occurred within TEC and airglow depletions observed over Texas. Finally, scintillation properties including severity and rapidity, and associated TEC signatures are comparable to those associated with equatorial spread F.

Investigating Ionospheric Scintillation Effects on Multifrequency GPS Signals

Over the last 15 years, the satellite constellation of the global positioning system (GPS) has been modernized for more precise applications, with the introduction of the L2C and L5 signals. However, among other effects, they are susceptible to severe ionospheric effects, particularly in the equatorial and low-latitude regions. Equatorial plasma bubbles, resulting from the combination of the ionospheric electrodynamics with plasma instability mechanisms and thermospheric coupling, may generate irregularity structures with scale sizes ranging from hundreds of kilometers to a few meters (or less). Ionospheric irregularities may cause deep amplitude fades and phase shifts to transionospheric signals. That is, they are responsible for amplitude and phase scintillation, which degrade receiver operations and may cause failures and unavailability to positioning and navigation services under extreme conditions. The objective of the present work is to analyze ionospheric scintillation effects on the L2C and L5 GPS signals, to compare their vulnerabilities with those of the L1 signal. The data used in this analysis were collected between November 2014 and March 2015, during the maximum solar activity of cycle 24 (a period of great scintillation incidence), by scintillation monitors deployed at four different sites in the Brazilian territory: Fortaleza, Presidente Prudente, Sao Jose dos Campos, and Porto Alegre. Intensity fades will be analyzed, considering different thresholds, to reveal their empirical probability distributions of scintillation occurrence, average fading occurrences and durations. The results will show that greater probabilities of strong scintillation occurrences are present in the modernized signals, reaching up to five times more events in the L5 signal in comparison with those in the legacy L1 signal. It will be shown that the L5 average fade duration is distinctly longer than the corresponding ones for the other frequencies, considering the same site, threshold, and L1 amplitude scintillation level. The results will also show that the average fade duration decreases according to the average ratio 0.6 s/3 dB within the threshold range from − 6 to − 15 dB, considering the same amplitude scintillation level and location.

Pseudorange-bias characteristics and the weakening method of BDS satellites

The nonideal characteristics of a navigation satellite signal will cause a pseudorange bias, which is manifested by the same type of receiver with the same pseudorange biases and different types of receivers with different pseudorange biases. When the technical state of receivers providing the navigation product is inconsistent with that of the users, the pseudorange bias will cause degradation of navigation and positioning service performance. In this paper, the pseudorange bias of BDS (Beidou Satellite Navigation System) is calculated using the ultrashort baseline pseudorange double-difference O−C (Observation Minus Computation) method. A large bias of B1I is obtained between two different juxtapositional receivers in the early stage of the experimental satellites. Thereafter, three methods, including the adjustment of the parameters of the loop of the receiver, a change in the multipath reduction algorithm, and an adjustment of the filter parameter of the predistortion of the satellite, are designed to reduce the bias. Experimental results indicate that the adjustment of parameters of the loop of the receiver can significantly reduce the pseudorange bias between the satellites, and the standard deviation of the pseudorange bias of B1I can be reduced from 0.63 to 0.36 m. Compared with the antimultipath observation, the observation of a narrow correlation can significantly reduce the pseudorange bias, and the standard deviation of the pseudorange bias of BII can be reduced from 0.36 to 0.18 m. Further, an adjustment of the filter parameters of the predistortion of the satellite can reduce the pseudorange bias of a single satellite by 0.3–0.4 m. There is no fixed reference satellite to evaluate the pseudorange biases of BDS satellites. A non-real-time double-difference O−C method that is based on the same external time and frequency controls of different receivers is designed to calculate the pseudorange bias. Employing this method, the characteristics of the pseudorange biases of BDS and GPS (Global Positioning System) satellites are compared. It is confirmed that (1) pseudorange biases exist in both BDS and GPS satellites, (2) the pseudorange bias of the L2C signal of GPS satellites is equivalent to that of the B1C data branch of BDS satellites, (3) the pseudorange bias of L1CA of GPS satellites is equivalent to the interoperable B1C pilot branch of BDS satellites, and (4) the pseudorange bias of L5C of GPS satellites is larger than that of the interoperable B2a signal of BDS satellites.

Modeling multifrequency GPS multipath fading in land vehicle environments

The reliability and performance of GPS receivers depend on the quality of the signal received, which can be largely affected by the interference caused by buildings, trees, and other obstacles. Since obstacles are always present in practical applications, several statistical representations have been developed along the years to measure, predict, and compensate errors induced by interferences. Two of the most used models to characterize GPS signal fading are the Nakagami-m and Rice, but in this work, we present evidence that supports the κ–μ distribution as the best fit to deal with multifrequency GPS multipath channels inside urban, rural, and forest areas. A synthetic signal simulator was developed to create propagation cases involving scattering clusters and specular reflections. Additionally, experimental measurements are presented to confirm the κ–μ distribution as the best distribution to characterize different situations on the available three GPS frequencies. We then present typical values of fading coefficients in L1, L2C, and L5 signals, for cases involving urban canyons, regular urban, rural, and dense vegetation areas. These coefficients can also be used to evaluate the receiver performance under similar cases or may be applied in weights measurement methods for positioning computation improvement.

Impact of flex power on GPS Block IIF differential code biases

GPS Block IIF satellites are able to redistribute the transmit power between the signal components. This ability is called flex power, and it has been developed as a remedy against jamming. Since it is operationally not possible to increase the transmit power for all signal components simultaneously, a redistribution between them is necessary under certain operational situations. Flex power has been active on Block IIF satellites since January 2017 over a specific regional area and has an impact on differential code bias estimation as well as the signal-to-noise density ratio. A network of the International GNSS Service stations containing only Septentrio PolaRx5 and PolaRx5TR receivers between August 1 and November 21, 2019 has been used for differential code bias estimation using GPS L1 C/A, L1 P(Y), L2 P(Y), and L2C signals with and without consideration of the flex power in the estimation process for Block IIF satellites. The estimation results are compared with the German Aerospace Center as well as the Chinese Academy of Sciences DCB products to validate the results.

Coherency evaluation of GNSS MBOC pilot and data signal in joint tracking

The MBOC signal uses a modulation in which the pilot and the data signals are separated. However, these modulation methods have evolved a variety of joint receiving algorithms. The paper introduces...

Copernicus Sentinel–3B – GPS L2C tracking tests during commissioning phase

Abstract The Copernicus Sentinel–3B, the twin satellite of Copernicus Sentinel–3A, was launched on 25 April 2018. During its commissioning phase, the radar altimeter satellite has been flying in tandem with Sentinel–3A, only 30 s apart. This was mainly done for calibration and validation of the instruments on-board Sentinel–3B, maximizing the correlation of measurements taken by both Sentinel–3 satellites. The commissioning phase of Sentinel–3B and thus the tandem flight with Sentinel–3A has also been used to do several tests with the RUAG GPS receivers on-board Sentinel–3B. Future missions like the Copernicus Sentinel–C and –D satellites and the Copernicus Sentinel–6 (Jason-CS) satellite will carry an enhanced RUAG GNSS receiver (PODRIX). The GPS receivers on Sentinel–3B already have the capability to track the GPS L2C signal, which will become important for the future when the number of GPS satellites transmitting the L2C signal increase from currently 19 satellites up to the full GPS constellation. To test the receiver’s L2C tracking performance, the redundant receiver on Sentinel–3B has been running in parallel to the main receiver with L2C tracking enabled, either exclusively or in a mixed P(Y)&L2C configuration. The performance of this new signal is analysed in detail. The Sentinel–3B POD processing chain running at the Copernicus POD Service is used to determine orbits based on the P(Y) signals from the main receiver and based on C/A plus the new L2C signal from the redundant receiver, all of them publicly available via the Copernicus Open Access Hub. The Sentinel–3B POD performance is compared to that of Sentinel–3A and the results of the Sentinel–3B redundant receiver are directly compared to the results of the main receiver. Results are compared in terms of observation metrics, estimated orbit parameters and differences to internal and external orbit products. External orbit validation is done with Satellite Laser Ranging (SLR) measurements to the satellites. Although only 19 GPS satellites are currently broadcasting the L2C signal, the resulting orbits are of equivalent quality as the operational orbit products based on P(Y) data from the full GPS constellation. SLR mean and standard deviation of 0.37 ± 1.32 cm and 0.39 ± 1.43 cm for the main and redundant receiver solutions, respectively, confirm the orbit accuracy independent of the signals used for POD. The percentage of more than five observations per epoch is still very low with approx. 15% considering the current L2C capable GPS constellation. Increase of this percentage is analysed based on a step-wise increase of the L2C capable GPS satellites up to a GPS constellation of 31 satellites.