GPS World

Tag: Polar

  • SSTL demonstrates new GNSS-R capabilities

    The successful demo consolidates concept designs for a proposed land-sensing ESA Scout mission, HydroGNSS

    Surrey Satellite Technology Ltd. (SSTL) has successfully demonstrated GNSS reflectometry (GNSS-R) from its 18-kg DoT-1 satellite. SSTL has pioneered the new field of GNSS-R with successful payloads on board TechDemoSat-1 and the CYGNSS constellation, and is continuing to develop the technology and data analysis in pursuit of this new science.

    SSTL's DoT-1 satellite
    SSTL’s DoT-1 satellite was launched in 2019. (Photo: SSTL)

    The GNSS-R payload onboard the DoT-1 satellite is incorporated within a new small-form-factor Core Avionics module integral to all SSTL’s future satellite platforms. This innovation paves the way for any SSTL satellite that can accommodate a nadir pointing antenna to become part of a GNSS-R small-sat constellation.

    GNSS reflectometry is an Earth-observation technique that uses GNSS signals as L-band radar sources, allowing the satellite to take measurements of ocean wind speeds, polar ice and hydrological land parameters, at a higher spatial resolution and an order of magnitude lower cost than other methods.

    “GNSS-R is a powerful new science that can contribute valuable data to help monitor changes in our global climate, and I am really pleased with the success of our DoT-1 demonstration.,” said Phil Brownnett, managing director of SSTL. “We now have an advanced instrument design and deep expertise in this new field, and I am hopeful that SSTL’s HydroGNSS concept will progress to a full mission to support the global climate-control challenge.”

    HydroGNSS mission

    The GNSS-R technology demonstration from SSTL’s DoT-1 satellite is also an important stepping stone for a proposed European Space Agency (ESA) Scout Mission Concept called HydroGNSS, which comprises two 40-kg satellites that collect data continually in near-polar orbits, taking hydrological measurements over the whole globe.

    The HydroGNSS mission concept makes advanced use of new GNSS reflectometry techniques such as Galileo signals, dual polarization, and coherent signal acquisition to measure four Essential Climate Variables (ECVs) over land: soil moisture, inundation, permafrost freeze/thaw, and biomass. HydroGNSS has been down-selected by ESA for a concept study; the finally selected Scout mission will commence in 2021.

    The below animated video illustrates the HydroGNSS mission.

    SSTL’s GNSS-R instrument collects and processes measurements into a “delay Doppler map” (DDM) that can be corrected and inverted into Level 2 products such as ocean wind speed, as has already been successfully demonstrated by the SSTL GNSS-R instruments onboard the TechDemoSat-1 and CYGNSS missions.

    The plot below shows results from data gathered by the DoT-1 satellite on Aug. 12, and shows simultaneous DDMs from four separate GPS satellites. As this is a forward scattering technique, the stronger signals with redder peaks indicate a calmer ocean with lower wind speeds. Approximately 40 minutes of data were collected from the Pacific to the Antarctic to the Southern Ocean.

    DoT-1 sub-satellite track (white) and GPS reflection tracks (yellow) collected during 40 minute data operation. (Image: SSTL)
    DoT-1 sub-satellite track (white) and GPS reflection tracks (yellow) collected during 40 minute data operation. (Image: SSTL)
    Four Delay Doppler Maps (DDMs) collected by DoT-1 that show signal reflections from four GPS satellites. (Image: SSTL)
    Four Delay Doppler Maps (DDMs) collected by DoT-1 that show signal reflections from four GPS satellites. (Image: SSTL)

    Soil moisture measurements

    Data from the SSTL GNSS-R instruments onboard the CYGNSS mission have demonstrated the potential for soil moisture measurement by GNSS reflectometry, and preliminary work shows that GNSS-R also has good sensitivity for freeze/thaw sensing in the active zone of permafrost. Unseasonal changes in the permafrost cycles could potentially release larger quantities of methane, which risks exacerbating global climate change.

    GNSS-R can also be used to assess biomass, a measure of forest density which acts as a vital sink for removing carbon dioxide from the atmosphere. In addition to longer term climate observations, soil moisture and inundation measurements from GNSS reflectometry can provide important information for short-term operational purposes, for example, towards Numerical Weather Prediction and flood warnings following rainfall events.

    The development of SSTL’s new GNSS-R instrument was funded in part by the European Space Agency.

  • Ground system ready for Joint Polar Satellite launch

    The northernmost Joint Polar Satellite System Common Ground System station in Svalbard, Norway. (Photo: Raytheon)
    The northernmost Joint Polar Satellite System Common Ground System station in Svalbard, Norway. (Photo: Raytheon)

    Newest version of Raytheon’s Joint Polar Satellite System Common Ground System is now operational

    Raytheon’s next-generation Common Ground System for the Joint Polar Satellite System (JPSS CGS 2.0) is now operational, supporting 11 polar-orbiting satellites and delivering observations to NOAA’s National Weather Service almost 50 percent faster than before.

    Svalbard, Norway, is the location of the northernmost Joint Polar Satellite System Common Ground System station.

    JPSS CGS 2.0 was designed to support the upcoming NASA launch of NOAA’s JPSS-1 satellite on Nov. 14.

    “The new ground system significantly improves the mission capabilities of the JPSS program,” said Matt Gilligan, vice president of Raytheon’s Navigation and Environmental Solutions. “It can handle even more data from the full constellation of satellites now and in the future.”

    Developed by NASA for NOAA, the JPSS CGS collects and disseminates observations from polar-orbiting weather satellites from the United States, Europe and Japan.

    The polar orbiters provide critical weather and environmental data to ensure meteorologists and forecasters have robust, reliable information to make timely and accurate weather predictions that help save lives, protect property and decrease the devastating economic impact caused by severe weather.

  • $2.6 Billion GPS Fitness Device Market Overshadowed by Smart Devices and Wearables

    ​Despite major GPS fitness device OEMs announcing new fitness products at January’s International Consumer Electronics Show in Las Vegas, it looks like an increasingly difficult battle between smart devices and wearables, according to analysts at ABI Research.

    Garmin launched its Vivofit fitness band and Vivoki/Vivahub corporate wellness solution. Magallen is one of the few companies in the GPS device OEM space that continues to show flashes of innovation, opening up its Echo watch platform to a range of third-party smartphone application developers.

    At the high-end of the GPS fitness watch market, Polar has launched a new multi-sport watch, which features a barometric pressure sensor, support for new features such as a cycling power pedal. TomTom has launched an iOS application that links its current GPS watch range to an iPhone via Bluetooth.

    In ABI Research’s quarterly GPS/GNSS Device tracker, the impact of these new device categories on dedicated GPS fitness device growth can be fully seen. Senior analyst Patrick Connolly comments, “Our forecasts for the overall GPS-enabled fitness area remain strong, hitting $2.6 Billion in 2018, but as was the case with turn-by-turn navigation, converged devices and wearables will take an increasing part of the available market. The adage of keeping what we have is important here, retaining a firm eye on growth in professional users, with hardware and in particular eyewear, a major distinguisher.”

    Practice director Dominique Bonte adds, “Of the announcements, Garmin’s move into corporate wellness was the most striking. We are about to see a huge technological shift in the corporate/business sector, around BYOD, BYOW, wellness, security, and efficiency. What is interesting is that Garmin does not include a location element, which will be a core enabler in this sea change.”

    The findings are part of ABI Research’s Location Devices Research Service.

  • Polar Launches Integrated Training Device, RC3 GPS

    Polar, a heart-rate training technology company, has released the RC3 GPS wrist device, a new training device with fully integrated GPS.

    The RC3 GPS has been developed to provide sports and fitness enthusiasts with an all-in-one training device with the GPS technology built in. Ergonomically designed, with naturally placed buttons, the RC3 GPS has a breathable wristband for maximum comfort, Polar said. Weighing 58 grams and measuring 1.37-centimeters in depth, the device has a huge digital display that makes it easy to read and customizable, allowing a user to display up to three rows of training data.

    The RC3 GPS combines the latest GPS technology with “Smart Coaching” — training guidance and features developed by Polar over the last 35 years. The device contains a wide range of easy-to-use heart rate based features including “Sports Profile,” where users preselect a sport and can monitor intensity specific to the demands of that discipline, and “Training Benefit,” where instant intuitive feedback is given straight after exercise.

    The RC3 GPS also includes the “Back to Start” GPS feature that directs users back to their starting point in the shortest distance possible. RC3 GPS users can now check out the more adventurous routes and explore them knowing that at the touch of a button they can be directed back to their starting place.

    The RC3 GPS uses SiRFstar IV technology. It has a 250 mAH Li-Pol fixed rechargeable battery that allows users to train for up to 12 hours without the need to recharge.