Position Fixing Research Articles

A GUIDED REGISTRATION STRATEGY EMPLOYING VIRTUAL PLANES TO OVERCOME NON-STANDARD GEOMETRIES – USING THE EXAMPLE OF MOBILE MAPPING AND AERIAL OBLIQUE IMAGERY

Abstract. Mobile mapping (MM) is an intriguing as well as emerging platform and technology for geo-data acquisition. In typical areas of interest for MM campaigns, such as urban areas, unwanted GNSS multipath, non-line-of-sight effects, and IMU drifts may lead to deteriorated position fixes. In this work, we are proposing a novel technique to register MM and aerial oblique imagery. As aerial platforms are not affected by GNSS occlusions and are able to collect very-high resolution images, a co-registration of the data sets enables a) an independent verification of the platform’s accuracy and b) an adjustment of the MM data’s pose. Both data sets depict the scene from an entirely different perspective, which complicates the matching problem. Our approach is based on the assumption that common visible entities in both images are available, e.g. façade surfaces. By determining planes coinciding with these visible entities in object space, variances can be overcome. As the orientation of the data sets is known – MM data has an unknown accuracy – derived planes are employed to support a visibility hypothesis while storing image information for image registration in object space. This enables constraining search space to support the actual registration. Although the inhomogeneity of the data sets poses a challenge to a successful registration, we can show that our stepwise strategy of finding common visible entities, exploiting them to increase the resemblance of the data sets, and utilising accurate registration methods renders this matching scenario possible. In this paper, the algorithm is explained in detail, experimental results of significant steps will be shown, and possible extensions are discussed.

Offloading Positioning onto Network Edge

While satellite or cellular positioning implies dedicated hardware or network infrastructure functions, indoor navigation or novel IoT positioning techniques include flexible storage and computation requirements that can be fulfilled by both end‐devices or cloud back‐ends. Hybrid positioning systems support the integration of several algorithms and technologies; however, the common trend of delegating position calculation and storage of local geoinformation to mobile devices or centralized servers causes performance degradation in terms of delay, battery usage, and waste of network resources. The strategy followed in this work is offloading this computation effort onto the network edge, following a Mobile Edge Computing (MEC) approach. MEC nodes in the access network of the mobile device are in charge of receiving navigation data coming from both the smart infrastructure and mobile devices, in order to compute the final position following a hybrid approach. With the aim of supporting mobility and the access to multiple networks, an Information Centric Networking (ICN) solution is used to access generic position information resources. The presented system currently supports WiFi, Bluetooth LE, GPS, cellular and NFC technologies, involving both indoor and outdoor positioning, using fingerprinting and proximity for indoor navigation, and the integration of smart infrastructure data sources such as the door opening system within real smart campus deployment. Evaluations carried out reveal latency improvements of 50%, as compared with a regular configuration where position fixes are computed by mobile devices; at the same time the MEC solution offers extra flexibility features to manage positioning databases and algorithms and move extensive computation from constrained devices to the edge.

An Enhanced Non-Coherent Pre-Filter Design for Tracking Error Estimation in GNSS Receivers.

Tracking error estimation is of great importance in global navigation satellite system (GNSS) receivers. Any inaccurate estimation for tracking error will decrease the signal tracking ability of signal tracking loops and the accuracies of position fixing, velocity determination, and timing. Tracking error estimation can be done by traditional discriminator, or Kalman filter-based pre-filter. The pre-filter can be divided into two categories: coherent and non-coherent. This paper focuses on the performance improvements of non-coherent pre-filter. Firstly, the signal characteristics of coherent and non-coherent integration—which are the basis of tracking error estimation—are analyzed in detail. After that, the probability distribution of estimation noise of four-quadrant arctangent (ATAN2) discriminator is derived according to the mathematical model of coherent integration. Secondly, the statistical property of observation noise of non-coherent pre-filter is studied through Monte Carlo simulation to set the observation noise variance matrix correctly. Thirdly, a simple fault detection and exclusion (FDE) structure is introduced to the non-coherent pre-filter design, and thus its effective working range for carrier phase error estimation extends from (−0.25 cycle, 0.25 cycle) to (−0.5 cycle, 0.5 cycle). Finally, the estimation accuracies of discriminator, coherent pre-filter, and the enhanced non-coherent pre-filter are evaluated comprehensively through the carefully designed experiment scenario. The pre-filter outperforms traditional discriminator in estimation accuracy. In a highly dynamic scenario, the enhanced non-coherent pre-filter provides accuracy improvements of 41.6%, 46.4%, and 50.36% for carrier phase error, carrier frequency error, and code phase error estimation, respectively, when compared with coherent pre-filter. The enhanced non-coherent pre-filter outperforms the coherent pre-filter in code phase error estimation when carrier-to-noise density ratio is less than 28.8 dB-Hz, in carrier frequency error estimation when carrier-to-noise density ratio is less than 20 dB-Hz, and in carrier phase error estimation when carrier-to-noise density belongs to (15, 23) dB-Hz (26, 50) dB-Hz.

Movement activity and habitat use ofCarabus ullrichii(Coleoptera: Carabidae): The forest edge as a mating site?

AbstractSome carabid species are not restricted to a single habitat only, but use various types of habitats. In these species, relatively little is known about the utilization of occupied habitats and factors affecting their movement within these habitats. In this study, we focus on the movement activity of ubiquitousCarabus ullrichiiduring its reproductive period at the border of two types of habitats, a meadow and a forest. We tracked 21 adult individuals using radio telemetry and recorded in total 1,687 position fixes. Movement activity was associated with the type of habitat and specific environmental conditions such as time of the day and air temperature. Both sexes activated preferably at dusk and during the night, although males were most active at temperatures around 15°C, while females showed no preference for temperature. Males were able to walk as fast as females, but they were more associated with forest edge. We assume that the inner edge of the forest could be used as a mating site and after mating males stay there and wait for new females with which to mate, while fertilized females disperse into the surroundings. They moved further into the closed forest where they were likely looking for oviposition sites and food resources to support reproduction. Exclusively females were recorded to visit the meadow at a greater distance from the forest edge and their movements there were almost always direct.

INTEGRITY ANALYSIS OF REAL-TIME PPP TECHNIQUE WITH IGS-RTS SERVICE FOR MARITIME NAVIGATION

Abstract. Open sea and inland waterways are the most widely used mode for transporting goods worldwide. It is the International Maritime Organization (IMO) that defines the requirements for position fixing equipment for a worldwide radio-navigation system, in terms of accuracy, integrity, continuity, availability and coverage for the various phases of navigation. Satellite positioning systems can contribute to meet these requirements, as well as optimize marine transportation. Marine navigation usually consists of three major phases identified as Ocean/Coastal/Port approach/Inland waterway, in port navigation and automatic docking with alert limit ranges from 25 m to 0.25 m. GPS positioning is widely used for many applications and is currently recognized by IMO for a future maritime navigation. With the advancement in autonomous GPS positioning techniques such as Precise Point Positioning (PPP) and with the advent of new real-time GNSS correction services such as IGS-Real-Time-Service (RTS), it is necessary to investigate the integrity of the PPP-based positioning technique along with IGS-RTS service in terms of availability and reliability for safe navigation in maritime application. This paper monitors the integrity of an autonomous real-time PPP-based GPS positioning system using the IGS real-time service (RTS) for maritime applications that require minimum availability of integrity of 99.8 % to fulfil the IMO integrity standards. To examine the integrity of the real-time IGS-RTS PPP-based technique for maritime applications, kinematic data from a dual frequency GPS receiver is collected onboard a vessel and investigated with the real-time IGS-RTS PPP-based GPS positioning technique. It is shown that the availability of integrity of the real-time IGS-RTS PPP-based GPS solution is 100 % for all navigation phases and therefore fulfil the IMO integrity standards (99.8 % availability) immediately (after 1 second), after 2 minutes and after 42 minutes of convergence time for Ocean/Coastal/Port approach/Inland waterway, in port navigation and automatic docking, respectively. Moreover, the misleading information is about 2 % for all navigation phases that is considered less safe is not in immediate danger because the horizontal position error is less than the navigation alert limits.

Effects of different postures on three dimensional conformal therapy for head and neck tumors

Objective To investigate the effect of different postures in three dimensional conformal therapy for head and neck tumors. Methods 40 patients with head and neck cancer were selected as the research subjects.All patients were randomly divided into observation group and control group, 20 cases in each group.The observation group for neck shoulder film fixed position, the control group was the first film fixed position each patient, radiotherapy 10 times.The display error condition of different position fixing of the two groups was compared. Results There was no significant difference in the error of the two groups in the X direction (P>0.05). The Y direction error, Z direction error of observation group were (0.12±0.12)mm, (0.10±0.11)mm, which were significantly lower than those of the control group[(0.23±0.19)mm, (0.19±0.15)mm] (t=2.189, 2.163, all P<0.05). Set-up repeatability errors in the Y axis, error more than 2mm in the observation group was 14 times, the error rate was 7%, which in the control group was 40 times, the error rate was 20%, the observation group was significantly smaller than the control group, the differences were statistically significant(χ2=29.286, 7.236, all P<0.05). Set-up repeatability error in the Z axis, error more than 2mm in the observation group was 12 times, the error rate was 6%, which in the control group was 34 times, the error rate was 17%, the observation group was significantly smaller than the control group, the differences were statistically significant(χ2=29.286, 5.944, all P<0.05). Conclusion For the patients with head and neck cancer who received three-dimensional conformal radiotherapy, the positioning accuracy and repeatability of the head and neck shoulder film position is better, has higher clinical value, it is worth to be popularized. Key words: Head and neck neoplasms; Radoitherapy, conformal; Position

An Improved BLE Indoor Localization with Kalman-Based Fusion: An Experimental Study.

Indoor positioning has grasped great attention in recent years. A number of efforts have been exerted to achieve high positioning accuracy. However, there exists no technology that proves its efficacy in various situations. In this paper, we propose a novel positioning method based on fusing trilateration and dead reckoning. We employ Kalman filtering as a position fusion algorithm. Moreover, we adopt an Android device with Bluetooth Low Energy modules as the communication platform to avoid excessive energy consumption and to improve the stability of the received signal strength. To further improve the positioning accuracy, we take the environmental context information into account while generating the position fixes. Extensive experiments in a testbed are conducted to examine the performance of three approaches: trilateration, dead reckoning and the fusion method. Additionally, the influence of the knowledge of the environmental context is also examined. Finally, our proposed fusion method outperforms both trilateration and dead reckoning in terms of accuracy: experimental results show that the Kalman-based fusion, for our settings, achieves a positioning accuracy of less than one meter.

An Effective Terrain Aided Navigation for Low-Cost Autonomous Underwater Vehicles.

Terrain-aided navigation is a potentially powerful solution for obtaining submerged position fixes for autonomous underwater vehicles. The application of terrain-aided navigation with high-accuracy inertial navigation systems has demonstrated meter-level navigation accuracy in sea trials. However, available sensors may be limited depending on the type of the mission. Such limitations, especially for low-grade navigation sensors, not only degrade the accuracy of traditional navigation systems, but further impact the ability to successfully employ terrain-aided navigation. To address this problem, a tightly-coupled navigation is presented to successfully estimate the critical sensor errors by incorporating raw sensor data directly into an augmented navigation system. Furthermore, three-dimensional distance errors are calculated, providing measurement updates through the particle filter for absolute and bounded position error. The development of the terrain aided navigation system is elaborated for a vehicle equipped with a non-inertial-grade strapdown inertial navigation system, a 4-beam Doppler Velocity Log range sensor and a sonar altimeter. Using experimental data for navigation performance evaluation in areas with different terrain characteristics, the experiment results further show that the proposed method can be successfully applied to the low-cost AUVs and significantly improves navigation performance.

Ubiquitous and Seamless Localization: Fusing GNSS Pseudoranges and WLAN Signal Strengths

Ubiquitous global positioning is not feasible by GNSS alone, as it lacks accurate position fixes in dense urban centres and indoors. Hybrid positioning methods have been developed to aid GNSS in those environments. Fingerprinting localization in wireless local area networks (WLANs) is a promising aiding system because of its availability, accuracy, and error mechanisms opposed to that of GNSS. This article presents a low-cost approach to ubiquitous, seamless positioning based on a particle filter integrating GNSS pseudoranges and WLAN received signal strength indicators (RSSIs). To achieve accurate location estimates indoors/outdoors and in the transition zones, appropriate likelihood functions are essential as they determine the influence of each sensor information on the position estimate. We model the spatial RSSI distributions with Gaussian processes and use these models to predict RSSIs at the particle’s positions to obtain point estimates of the RSSI likelihood function. The particle filter’s performance is assessed with real data of two test trajectories in an environment challenging for GNSS and WLAN fingerprinting localization. Outcomes of an extended Kalman filter using pseudoranges and a WLAN position as observation is included as benchmark. The proposed algorithm achieves accurate and robust seamless localization with a median accuracy of five meters.

A Method for The Assessing of Reliability Characteristics Relevant to an Assumed Position-Fixing Accuracy in Navigational Positioning Systems

Abstract This paper presents a method which makes it possible to determine reliability characteristics of navigational positioning systems, relevant to an assumed value of permissible error in position fixing. The method allows to calculate: availability , reliability as well as operation continuity of position fixing system for an assumed, determined on the basis of formal requirements - both worldwide and national, position-fixing accuracy. The proposed mathematical model allows to satisfy, by any navigational positioning system, not only requirements as to position-fixing accuracy of a given navigational application (for air , sea or land traffic) but also the remaining characteristics associated with technical serviceability of a system. Essence of the method in question consists in the working-out of recorded empirical position-fixing data as well as the making use of multi-state Markov processes ( appropriate to a maximum error value permissible for various navigational applications ) as a result of which reliability characteristics based on real data would be determined. About usefulness of a given navigational positioning system for its possible application would decide a vector of variables (both dealing with position and reliability) which satisfies / or does not satisfy / formal navigational requirements for a given application.

Competition policy in the global era

ABSTRACTI discuss some of the implications of globalization to the design and application of competition policy. My analysis is divided into three different areas: price fixing, mergers and abuse of dominant position. I also consider the importance of China as an emergent player in the global competition policy arena.

Apparent source levels and active communication space of whistles of free-ranging Indo-Pacific humpback dolphins (Sousa chinensis) in the Pearl River Estuary and Beibu Gulf, China.

Background. Knowledge of species-specific vocalization characteristics and their associated active communication space, the effective range over which a communication signal can be detected by a conspecific, is critical for understanding the impacts of underwater acoustic pollution, as well as other threats.Methods. We used a two-dimensional cross-shaped hydrophone array system to record the whistles of free-ranging Indo-Pacific humpback dolphins (Sousa chinensis) in shallow-water environments of the Pearl River Estuary (PRE) and Beibu Gulf (BG), China. Using hyperbolic position fixing, which exploits time differences of arrival of a signal between pairs of hydrophone receivers, we obtained source location estimates for whistles with good signal-to-noise ratio (SNR ≥10 dB) and not polluted by other sounds and back-calculated their apparent source levels (ASL). Combining with the masking levels (including simultaneous noise levels, masking tonal threshold, and the Sousa auditory threshold) and the custom made site-specific sound propagation models, we further estimated their active communication space (ACS).Results. Humpback dolphins produced whistles with average root-mean-square ASL of 138.5 ± 6.8 (mean ± standard deviation) and 137.2 ± 7.0 dB re 1 µPa in PRE (N = 33) and BG (N = 209), respectively. We found statistically significant differences in ASLs among different whistle contour types. The mean and maximum ACS of whistles were estimated to be 14.7 ± 2.6 (median ± quartile deviation) and 17.1± 3.5 m in PRE, and 34.2 ± 9.5 and 43.5 ± 12.2 m in BG. Using just the auditory threshold as the masking level produced the mean and maximum ACSat of 24.3 ± 4.8 and 35.7 ± 4.6 m for PRE, and 60.7 ± 18.1 and 74.3 ± 25.3 m for BG. The small ACSs were due to the high ambient noise level. Significant differences in ACSs were also observed among different whistle contour types.Discussion. Besides shedding some light for evaluating appropriate noise exposure levels and information for the regulation of underwater acoustic pollution, these baseline data can also be used for aiding the passive acoustic monitoring of dolphin populations, defining the boundaries of separate groups in a more biologically meaningful way during field surveys, and guiding the appropriate approach distance for local dolphin-watching boats and research boat during focal group following.

Importance of the antenniform legs, but not vision, for homing by the neotropical whip spider Paraphrynus laevifrons.

Amblypygids, or whip spiders, are nocturnal, predatory arthropods that display a robust ability to navigate to their home refuge. Prior field observations and displacement studies in amblypygids demonstrated an ability to home from distances as far away as 10 m. In the current study, micro-transmitters were used to take morning position fixes of individual Paraphrynus laevifrons following an experimental displacement of 10 m from their home refuge. The intention was to assess the relative importance of vision compared with sensory input acquired from the antenniform legs for navigation as well as other aspects of their spatial behavior. Displaced individuals were randomly assigned to three treatment groups: (i) control individuals; (ii) vision-deprived individuals, VD; and (iii) individuals with sensory input from the tips of their antenniform legs compromised, AD. Control and VD subjects were generally successful in returning home, and the direction of their movement on the first night following displacement was homeward oriented. By contrast, AD subjects experienced a complete loss of navigational ability, and movement on the first night indicated no hint of homeward orientation. The data strongly support the hypothesis that sensory input from the tips of the antenniform legs is necessary for successful homing in amblypygids following displacement to an unfamiliar location, and we hypothesize an essential role of olfaction for this navigational ability.

Gao's double-way approach for laparoscopic D2 radical surgery for gastric cancer.

Laparoscopic D2 radical surgery for gastric cancer is minimally invasive but complex. In this path: (1) Repeated operation of lesser curvature side; (2) The gastrohepatic ligament is relatively fixed. Hence, it is not easy to expose the suprapancreatic area; and (3) It is not easy to dissect No. 1, 12 lymph nodes. This area may not be sufficiently cleaned or surrounding vessels may be injured during a resection. So it is critical to choose position fixing, and a clear, fast and convenient operation path. The author, based on his experience, has established a set of procedural steps called "Gao's double-way", lesser omentum approach and traditional greater omentum approach, which are described in detail in this article. The path of this first approach is described as a "W" type of dissection. The second way is the traditional greater omentum approach, whose path is described as a "M" type of dissection. This will enable laparoscopic surgeons to select a suitable path. This new approach not only simplifies the surgery but also provides more space for the subsequent operation, thereby making the surgery more simple, safe and easy.

클린룸 내 다관절 로봇 주위의 유동해석

We carried out three-dimensional flow analysis in a clean room. Flow field in a robot experiment system, induced from the moving robot, is numerically studied in this paper. The effects of moving robot in a clean room are investigated in order to find the section of dust accumulation. Contamination on the bottom produced from the moving robot is predicted from the analysis results from the flow fields. Results show that a large swirl flow is formed around the moving robot. Consequently, the optimal flow condition can be obtained by controlling the fluid velocity through the fixing of inlet or outlet position.

A path reconstruction method integrating dead-reckoning and position fixes applied to humpback whales.

BackgroundDetailed information about animal location and movement is often crucial in studies of natural behaviour and how animals respond to anthropogenic activities. Dead-reckoning can be used to infer such detailed information, but without additional positional data this method results in uncertainty that grows with time. Combining dead-reckoning with new Fastloc-GPS technology should provide good opportunities for reconstructing georeferenced fine-scale tracks, and should be particularly useful for marine animals that spend most of their time under water.We developed a computationally efficient, Bayesian state-space modelling technique to estimate humpback whale locations through time, integrating dead-reckoning using on-animal sensors with measurements of whale locations using on-animal Fastloc-GPS and visual observations. Positional observation models were based upon error measurements made during calibrations.ResultsHigh-resolution 3-dimensional movement tracks were produced for 13 whales using a simple process model in which errors caused by water current movements, non-location sensor errors, and other dead-reckoning errors were accumulated into a combined error term. Positional uncertainty quantified by the track reconstruction model was much greater for tracks with visual positions and few or no GPS positions, indicating a strong benefit to using Fastloc-GPS for track reconstruction. Compared to tracks derived only from position fixes, the inclusion of dead-reckoning data greatly improved the level of detail in the reconstructed tracks of humpback whales. Using cross-validation, a clear improvement in the predictability of out-of-set Fastloc-GPS data was observed compared to more conventional track reconstruction methods. Fastloc-GPS observation errors during calibrations were found to vary by number of GPS satellites received and by orthogonal dimension analysed; visual observation errors varied most by distance to the whale. ConclusionsBy systematically accounting for the observation errors in the position fixes, our model provides a quantitative estimate of location uncertainty that can be appropriately incorporated into analyses of animal movement. This generic method has potential application for a wide range of marine animal species and data recording systems.Electronic supplementary materialThe online version of this article (doi:10.1186/s40462-015-0061-6) contains supplementary material, which is available to authorized users.

Preparing an autonomous, low-cost GNSS positioning and timing function on board a GEO telecom mission: a study case

The purpose of this paper is to present a viable solution for a low-cost, autonomous GNSS positioning and timing function integrated in the avionics of a GEO telecomm satellite. This paper is based on a study currently carried out by Thales Alenia Space under an ARTES contract with ESA, funded by the Italian Space Agency. The availability of an autonomous means of positioning in GEO platform is essential in reducing the constraints on the ground control. This is even more true in the case of the transfer to the GEO orbit, where the current trend is to implement the low-thrust electrical propulsion and this phase could have a duration of months: the GNSS function can autonomously feed the on-board trajectory propagator with the spacecraft position fixes, in order to constrain the state estimate of the on-board filter. In order to achieve large availability of position and timing of the hosting platform, the tracking of the GNSS antenna side lobes is a critical feature. Based on the recent experiences of SGR GEO, additional insights on the side-lobe levels were made available to the GNSS community and this allows to better target a receiver architecture whose performance can be more precisely determined for the study case. This paper will show the findings in terms of GNSS function architecture for the GEO application, as well as the integration of this function inside the avionic computer. The focus is on a single frequency receiver, targeting at least GPS L1 and Galileo E1 signals. Optimizations in terms of sharing of HW resources with the on-board computer (oscillator, DC/DC converter) and the overall redundancy strategy are presented. Extension and implications for covering to the GTO case is presented as well. The expected receiver performances (position and timing accuracy, autonomy) are provided through in-orbit simulations, including a realistic receiver model.

TDOA 방위탐지방식의 위치표정 정확도

Abstract The technology of direction finding is very important to make high position fixing accuracy. TDOA(time difference of arrival) direction finding technology is a high accuracy technology and is used in RF system from 1990. The principle of TDOA is to receive an emitter signal with two antennas, measure the time difference of received signal and then convert the time differences to azimuth angle. For high DF(direction finding) accuracy long basis line and high SNR at receiving system are needed. The DF accuracy and position fixing accuracy are simulated with different SNRs and antenna base lines. We obtain the DF accuracy of 0.51 o at 0 o incident azimuth angle in case of 50m base line and 40dB SNR. Key Words : Position Fixing, SNR, Direction Finding, TDOA, CEP, Position Error Received 27 September 2014, Revised 27 October 2014Accepted 20 November 2014Corresponding Author: Gyoo-Soo Chae(Baekseok University) Email: gschae@bu.ac.krⒸ The Society of Digital Policy & Management. All rights reserved. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is ISSN: 1738-1916 properly cited.

INTEGRITY CONTROL OF MEASURED PSEUDORANGE USING RAIM ALGORITHM

The article describes the basic principles for vessel’s position fixing, using pseudorange measurements of satellite navigation systems, under negative effect of promiscuous random and systematic errors. The definition «integrity of navigation information» is interpreted as degree of confidence of the ship’s positioning. The main objective of current paper is analysis of the on-board integrity monitoring method using a stand-alone algorithm, founded on a law of normal distribution of random variables and statistical data processing. The scientific novelty of the work is establishment of mathematical dependences between ship’s mean square position error and the test statistic of the algorithm which has been performed by least squares. The scientific result of the paper is demonstration of the effectiveness of autonomous integrity monitoring algorithm as tool of improvement of safe navigation, which able not only identify the source of ship’s positioning errors but also to exclude such testimony from further processing.

The effect of bladder cancer cell 5637 invasiveness by heparanase through the cation-independ mannose 6-phosphate receptor pathway

Objective To study the relationship between heparanase and cation-independ mannose 6-phosphate receptor (CD222) expression in bladder cancer 5637 cell line.And find out the effect of cell invasiveness by their combination.Methods Immunofluorescence assay were used to detect the position fixing and interaction of heparanase and CD222 in bladder cancer 5637 cell line.The CD222 mRNA-targeted small interfering RNA (siRNA) were designed and constructed.5637 cells were cultured and transfected with siRNA-CD222.The expression of CD222 mRNA and protein were examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting.After the recombinant human heparanase were given.Western blotting were performed to detect the expression of CD222 and p-Akt in 5637 cell line before and after tansfection.The invasiveness of above cells were determined by matrigel invasion assays.Results Heparanase and CD222 staining on the cell cytoplasm.Heparanase binds CD222 and cells treated with recombinant human heparanase enhance the binding.Inhibition of CD222 expression in 5637 by siRNA could decrease invasion capacity and the level of Akt phosphorylation which was induced by recombinant human heparanase.Conclusion Heparanase binding to CD222 were localized to the cell cytoplasm and heparanase facilitates bladder cancer cell invasiveness by binding to CD222 and increasing Akt phosphorylation. Key words: Bladder cancer; Hparanase; Cation-independ mannose 6-phosphate receptor; Small interfering RNA; Invasiveness