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Dear Friends, Me and my colleagues are trying to make an application for routing purposes. This application has to be in a mutual transaction with a GPS tracking device obviously. Here come the issues we encounter 1. We are getting the login data but after that we need to send response to device with a format that device can verify server and then send actual GPS data to server. 2. We are not able to send login data to that device so that's why device not send us GPS data. 3. Login Data we are getting is like :- 2323101501f357367031649441529625060. 4. We are not getting further process what to do to get Device GPS data to our server. We have asked for the GPS device support, no useful information but offering their own portal. and here is the code developed for this transaction : package com.trackit; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.net.ServerSocket; import java.net.Socket; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; public class ServerListener { public static void main(String[] args) { new ServerListener().startServer(); } public void startServer() { final ExecutorService clientProcessingPool = Executors.newFixedThreadPool(03); Runnable serverTask = new Runnable() { @SuppressWarnings("resource") @Override public void run() { try { ServerSocket serverSocket = new ServerSocket(5094); System.out.println("Waiting for clients to connect..."); while (true) { Socket clientSocket = serverSocket.accept(); clientProcessingPool.submit(new ClientTask(clientSocket)); } } catch (IOException e) { System.err.println("Unable to process client request"); e.printStackTrace(); } } }; Thread serverThread = new Thread(serverTask); serverThread.start(); } private class ClientTask implements Runnable { private final Socket clientSocket; private ClientTask(Socket clientSocket) { this.clientSocket = clientSocket; } @Override public void run() { System.out.println("Got a client !"); try { BufferedReader reader = new BufferedReader( new InputStreamReader(clientSocket.getInputStream())); String clientData = ""; clientData = reader.readLine(); String hex_value = asciiToHex(clientData); System.out.println("Hex Value :-"+hex_value); } catch (IOException e) { e.printStackTrace(); } } private String asciiToHex(String clientData) { char[] chars = clientData.toCharArray(); StringBuffer hex = new StringBuffer(); for (int i = 0; i < chars.length; i++) { hex.append(Integer.toHexString((int)chars[i])); } return hex.toString(); } } } Any kind of tips and help is appreciated. Kindly Regards

Hello friends, I think geospatial software (commercial and free), user cases, and problem solving issues related to people who uses mac as operative system, would worth having. I will list only a few of them (the ones I use or am interested in) to show that out there it might be a potential pool of users interested of what gisarea has to offer: tutorials, software, and solutions based on users' knowledge and experiences. Here is the gis/remote sensing list of software available for mac: qgis saga spatialite grass gis otb/monteverdi2 envi/idl tntmips postgresql/postgis cartographica Usually, installation and troubleshooting of software on mac is quite different than windows, so having a topic forum dedicated to all things mac will help a lot of users. Also, for people that use ArcGIS virtualized on mac (as I do) would be great to have a place to go. Please fell free to share your thoughts! Cheers, GSQ

Author: Daniel Macias Valadez, GNSS Analyst at Effigis Original text available here: http://bit.ly/1IYSbNY GPS, being the pioneer of all Global Navigation Satellite Systems (GNSS), is the only system that has remained fully operational for civilian use for more than two decades. The number of civilian applications has exploded in recent years and its popularity is undisputed. Other GNSS have had issues (GLONASS during the end of the 90s and the 00s) or are still incomplete (Galileo, BeiDou). This helps explain the fact that a large percentage of the population is familiar with the term “GPS”, but not so for the other GNSS: GLONASS, Galileo, BeiDou. However, these other systems are expected to catch up in a few years so GPS must maintain its edge and remain competitive. Since the beginning of GPS, technical and performance improvements have been regularly implemented in each new generation (called “Block”) of GPS satellites launched. However, due to the relatively long lifespan of the satellites (between 8 and 20 years), and the fact that satellites are replaced progressively (one or two per year on average), the effects of the performance improvements are gradual and often go unnoticed. During the first generations of GPS, most improvements concerned satellites and the equipment inside them (improvement in clock performance, improvements in satellite autonomy and design, etc.). However, beginning with Block IIR-M, whose first satellite was launched in 2005, new GPS signals have been added. These new signals have several improvements, which, from the user perspective, are interesting because they enable enhanced positioning accuracy and reliability. Before introducing these new signals, let me give you a brief summary of currently used (legacy) GPS signals. Image: Block IIR-M Legacy Signals: L1 C/A, L1P(Y) and L2P(Y) From the beginning, GPS satellites have transmitted three main signals: one civilian signal (L1 C/A), and two encrypted military signals (L1P(Y) and L2P(Y)). As this implies, only one signal is available to civilian users. Military signals are transmitted in two different frequency bands: L1 (1575.42 MHz) and L2 (1227.60 MHz) and are encrypted. Having two bands is highly beneficial in improving accuracy and convergence time, since the undesired ionospheric effects can be greatly reduced. Since the 90s, designers of Geodetic-grade receivers have managed to access the encrypted L2P(Y) signal through a technique called “semi-codeless tracking”, and thus offer all the benefits of having two frequencies to civilian users. However, on the one hand, geodetic-grade receivers have a much higher price tag compared with low-end receivers, and, on the other hand, the techniques used to access the encrypted L2P signal introduce a slight signal degradation. L2C Signal As I previously mentioned, the benefits of receiving a second GPS signal in another frequency band are quite significant. With the ever-growing demand of civilian GPS applications, the U.S. Department of Defense (DoD) decided to include a new civilian signal on the L2 frequency band called L2C, beginning with block IIR-M satellites. Instead of just using a signal identical to legacy L1 C/A and transmitting it on L2, the L2C signal was redesigned to provide several technical improvements when compared with the L1 C/A signal. The L2C uses more sophisticated and modern modulation techniques, which offer the following advantages when compared with the legacy signal: Increased sensitivity or tracking threshold, which translates into an improvement in maintaining the tracking of the signal in unfavourable conditions, such as with obstructions or even indoors. Greater cross-correlation between signals, which enables a stronger tolerance to interference and multipath. Since the L2C is an unencrypted signal intended for civilian use, it is expected that even non-expensive, non-geodetic grade receivers will be able to receive and track the L2C signal. Even though the L2C signal looks promising, we still have to wait a few years before being able to take advantage of it. As of July 2015, out of 30 operational satellites, only 15 transmit L2C. It is expected that all satellites will transmit the L2C signal by 2020. Additionally, even though the first L2C transmitting satellite was launched in 2005, Block IIR satellites began transmitting usable navigation messages (updated daily) on December 31, 2014. However, according to the U.S. government’s GPS Web page, “L2C should continue to be considered pre-operational and should be employed at the user’s own risk.” Once the full constellation of GPS satellites transmits the L2C signal, “The U.S. government encourages all users of codeless/semi-codeless GPS technology to plan on using the modernized civil signals by December 31, 2020, as P(Y) may change after that date.” L5 Signals After Block IIR-M, the next generation of satellites, Block IIF, offers a third civilian signal on another frequency band, the L5 band (1176.45 MHz). As opposed to the L2 band, this radio band is reserved exclusively for aviation safety services, and, as such, is expected to be favoured by civilian users over L2 in the future. The first Block IIF satellite was launched in 2010, and, as of July 2015, 8 Block IIF satellites are in operation. The L5 band will be entirely used for civilian signals and free of military signals. Thus, a more powerful signal, with higher bandwidth, when compared with L1 and L2, is transmitted in L5. The main advantages of the L5 signal are: the possibility to track weaker signals through a longer code sequence and better cross-correlations between codes. Additionally, the transmitted power is higher. better immunity to interference with its greater bandwidth, and thus greater spectrum spreading. ionospheric effect attenuation using an L1/L5 combination, similar to the L1/L2 combination. instantaneous or near-instantaneous ambiguity resolution for quicker fixed solution convergence given the use of a triple frequency (L1/L2/L5) signal combination. For a full L5 transmitting satellite constellation, we will have to be more patient than with the L2C full constellation. Whereas the latter is expected by 2020, the former will take several additional years. L1C Signal Compared with modern signals L2C and L5 in operation, the L1 C/A signal is less performant. It is necessary to upgrade it to be on par with the modernized signals. This is where the next generation of GPS satellites, Block III, comes into play. This block of satellites will include another modernized civil signal, the L1C, which will eventually replace the legacy L1 C/A signal. The characteristics of the L1C signal are similar with those of L2C and L5. The design and manufacturing of some of Block III satellites have already been completed, but no launch has taken place yet. First launch is expected during 2016. However, given the current pace of satellite replacement (which can change depending on economic and political unforeseen circumstances), a complete GPS constellation with L1C signals should take at least another decade. The Bottom Line Since the beginning of the new millennium, GPS professionals have impatiently been waiting for all new GPS signals to be fully deployed. Although it will not magically resolve all our current woes such as performance degradation in obstructed areas or long convergence time for a fixed solution, I believe that GPS modernization looks very promising. Legend: Spectrum Use of Legacy and New GPS Signals. Legacy signals: L1 C/A, L1 P(Y) and L2 P(Y). Note that the civilian signal uses the I (in-phase) component and the military signals use the Q (quadrature) component so that they can share the same band. New signals since Block IIR-M: L2C and since Block IIF: L5. Note that there are also new military signals (M) in L1 and L2. Also note that the L5 signal uses both components, I and Q. New signal since Block III: L1C. Note that this signal uses a type of modulation (BOC) that enables it to share the band and in-phase/quadrature component with legacy and military signals.

The first user-friendly and professional application for windows phone devices that performs advanced Gps calculations and mapping. Intended for surveying engineers, civil engineers, architects as well as those involved in real estate. Description of software features: Computation of coordinates of surveying points and subsequent mapping of the points on the map. Ability to store point data files on phone and Onedrive. Exporting final results of calculations in Drawing Exchange Format (DXF) which is compatible with the most popular design software or a simple text file of point details such as coordinates. The resulting mapping can be used for all surveying/topographical needs including amateur viewing of prospective real estate endeavors. Intuitive user interface, taking full advantage of the windows phone touch-screen capabilities, allowing the smooth use of the application in an outdoors environment. Mapping allows you the following views: * road/ aerial/ hybrid/ terrain Supported Coordinate Systems: • Universal Traverse Mercator (UTM) • British Grid (OSGB36) • Greek Grid 1987 (HGRS87 / ΕΓΣΑ 1987) http://www.windowsphone.com/en-us/store/app/gps-mapper/f1827bc8-c52e-4c2b-89fa-8a287b50cbe1

Right now I was tasked in cleaning static GPS observation, e.g. cleaning noise and disabling some satellite observation. I'm doing well until I can't get fix on some of the baselines, Then I asked my one of my fellow what are the techniques in cleaning gps observation, they just told me that what they do is trial and error. Now, I want to ask, if there is another way, like some science in spotting weak satellite observation and cleaning data with precision. Thanks, hope someone who is expert in this field will be able to give me some hints on how to do this precisely. BTW.. I am using licensed Trimble Business Center

Nexteq launches accelGRx, a platform for accelerating professional-grade GNSS receiver development. The platform provides open and production-ready hardware and software building blocks for GNSS receivers. accelGRx is ideal for organizations looking to research and develop new techniques and algorithms requiring deep in-receiver integreation or quickly produce a small, high performance receiver. accelGRx supports GPS L1 and Beidou B1, and the hardware is GLONASS and Galileo ready. It pairs a compact form factor and industry standard pin layout with a code and phase precision of 4 cm and 0.4 mm respectively for both GPS L1 and Beidou B1. It incorporates an array of software development tools, including the ability to record and play back digitized signals. An accelGRx licensee wil have tools to develop and test new deep in-receiver integration techniques and algorithms: • Access to all source code, logic and tools • Deep in-receiver access to real-time GNSS information • PC-based software model of receiver platform • Store and playback of digitized signals for development and testing • Testing with production-ready receiver and real-world conditions An accelGRx licensee will have the necessary assets and tools to begin commercialization immediately after development is complete: • Hardware design (schematic, PCB layout, and BOM) • FPGA logic design • Full tracking and PVT source code • Receiver operating system • Design documentation and manuals

Basic tutorial and manual for GPS and Total station https://www.dropbox.com/s/r4460yv9uwjqtaw/GIS_SOP.rar

Hi guys I've made some maps with Mapwell that I would like to use with my Garmin nuvi 3490. I have yet to figure out what type of format a "car GPS" uses. Is it .img just like the handheld ones? I've tried to put a .img file on the memory card, but the map won't display. Also tried loading the map with Garmin Mapinstall, but the map does not appear as an option. Any help would be greatly appreciated.