GPS World

Tag: GPS modernization

  • Qinetiq, Rockwell Demonstrate Multi-Constellation Galileo/GPS Secure Positioning for Governmental Applications

    On August 30, QinetiQ and Rockwell Collins demonstrated the first joint satellite navigation positioning using live signals from the encrypted governmental services from the U.S. Department of Defense (DOD) GPS Precise Positioning Service (GPS-PPS) and the new European Galileo Public Regulated Service (PRS). The signals on GPS L1 and L2, together with Galileo PRS L1A and E6A, were processed and combined to form multi-frequency, multi-constellation position fixes.

    Positioning, navigation and timing (PNT) services provided by GNSS, such as GPS and the forthcoming Galileo system, are essential to underpinning both commercial and economic activity (the EC estimates 6-7% of the developed world’s GDP) and the delivery of governmental responsibilities including the safety and security of citizens.

    GNSS systems such as GPS and Galileo make use of very low power signals and are subject to inadvertent interference, deliberate jamming and spoofing (where an attacker generates a false signal masquerading as a valid one to mislead a user receiver). Attacks on GNSS may range from low-level criminal nuisance (a delivery driver stopping their employer tracking them), enabling theft of high-value vehicles fitted with trackers, through to state-sponsored attacks. This is potentially a significant concern for a wide range of governmental users including law enforcement, security and emergency services, critical national infrastructure, transport and defense users. The use of multiple independent, secured navigation services provides significant improvements to navigation robustness and, along with other measures, offers substantial counters to these threats.

    “This has been our first opportunity to explore how secured navigation services on GPS and Galileo can be used together to provide users with critical reliance on PNT with robust and continuous navigation services,” Nigel Davies, Head of QinetiQ’s Secured Navigation Group said. “QinetiQ is proud to be a key, long-term contributor to the Galileo Programme, having been working closely with the European Space Agency (ESA), the European GNSS Agency (GSA), European industrial partners and European Member States since 2003.  QinetiQ and Rockwell Collins wish to thank ESA, the EC and GSA for support in accessing Galileo, as well as the UK Space Agency, UK Satellite Applications Catapult and the UK MOD for their support.”

  • The System: Autumn Falls Back

    The System: Autumn Falls Back

    Delta IV, the current GPS launch vehicle, awaits a date with space at Cape Canaveral.
    Delta IV, the current GPS launch vehicle, awaits a date with space at Cape Canaveral.

    Launch Delays Ground GPS IIF and Galileo FOC

    The scheduled October 23 launch of GPS IIF-5, the fifth in the current “follow-on” generation of GPS satellites, has been postponed in order to complete a review of an adjustment made to the rocket’s upper stage engine. A loss of thrust by a Delta IV rocket upper stage during a GPS launch last year worried the Air Force and the United Launch Alliance (ULA), though the satellite successfully reached its intended orbit.

    A subsequent  investigation identified a fuel leak in the engine system as the culprit. Two  medium Delta IV rockets and one heavy version have launched since then, but ULA said further investigation had produced new information about the engine’s first start.

    While no new launch date has been set, the ULA released a statement:

    “The ongoing Phase II investigation has included extremely detailed characterization and reconstructions of the instrumentation signatures obtained from the October 2012 launch and these have recently resulted in some updated conclusions related to dynamic responses that occurred on the engine system during the first engine start event.

    “The GPS IIF-5 Delta IV launch is being delayed to allow the technical team time to further assess these updated conclusions and improvements already implemented and determine whether additional changes are required prior to the next Delta IV launch.

    “The Delta IV booster for the GPS IIF-5 mission has completed the standard processing and checkout on the launch pad and will be maintained in a ready state for spacecraft mate and launch pending completion of this assessment. A new launch date will be established when the assessment of the updated dynamic response information is completed in the coming weeks.”

    A Soyuz rocket (right) will carry Galileo FOC satellites, but no sooner than June 2014.
    A Soyuz rocket (right) will carry Galileo FOC satellites, but no sooner than June 2014.

    Galileo. Continuing delays in ground testing of the first two fully operational Galileo satellites have postponed their launch to June 2014 at the earliest.

    According to European officials, the European Space Research and Technology Centre (ESTEC) thermal vacuum chamber for testing satellites under orbit conditions was not ready for the two FOC satellites delivered by OHB in late summer.

    The satellites thus cannot ship to the Guiana spaceport in South America in time for a planned 2013 launch on a Soyuz rocket. The Galileo schedule is also running into bottlenecks with scheduled launches by other satellite programs aboard Guiana Soyuzes.

    A six-week test of the first Galileo satellite at ESTEC reportedly got under way in October.

    Svalbard station on Spitsbergen in the Norwegian Arctic.
    Svalbard station on Spitsbergen in the Norwegian Arctic.

    Ground Network Supports Galileo for SAR

    Completion of a pair of European Space Agency dedicated ground stations at opposite ends of that continent has enabled Galileo satellites in orbit to participate in global testing of the Cospas–Sarsat search and rescue system.

    The Maspalomas station, in mid-Atlantic Canary Islands, was activated in June. In September, the Svalbard site on Spitsbergen in the Norwegian Arctic activated. The two sites can now communicate and will soon undertake joint tests.

    The International Cospas-Sarsat Programme is a satellite-based search and rescue (SAR) distress alert detection and information distribution system, established by Canada, France, Russia, and the United States, with participation by 33 other countries.

    Activation of the two new stations enables participation of the latest two Galileo satellites in a worldwide test campaign for Cospas-Sarsat expansion.
    The program is introducing a new medium-orbit SAR system to improve coverage and response times, with the Galileo satellites in the vanguard.

    The second pair of Europe’s Galileo satellites — launched together in October 2012 — are the first of the constellation to host SAR payloads. These can pick up UHF signals from emergency beacons aboard ships or aircraft or carried by individuals, which are then relayed to ground stations. There, the source is pinpointed and automatically passed on to a control center, which then routes it to local authorities for rescue.

    “The Galileo satellites, tested in combination with the same SAR payloads on Russian GLONASS satellites as well as compatible repeaters on a pair of U.S. GPS satellites, showed an ability to pinpoint simulated emergency beacons down to an accuracy of 2–5 kilometers in a matter of minutes,” explained Igor Stojkovic, ESA Galileo SAR engineer.

    “Our in-orbit validation tests so far have been in line with expectation and beyond, giving us a lot of confidence in the performance of the final system, once completed. And using a combination of satellites is just how the upgraded system will operate in practice, in order to localize distress signals.”

    Localization test performed from Maspalomas MEOLUT as part of Galileo’s SAR in-orbit validation. Beacon locations obtained with four satellites are shown in black, while those using three satellites are shown in grey. More than 93 percent of all beacon locations, after only a single beacon burst has been received, are within the required five kilometers from actual beacon position.
    Localization test performed from Maspalomas MEOLUT as part of Galileo’s SAR in-orbit validation. Beacon locations obtained with four satellites are shown in black, while those using three satellites are shown in grey. More than 93 percent of all beacon locations, after only a single beacon burst has been received, are within the required five kilometers from actual beacon position.

    System Briefs

    GLONASS Seeks UK Ground. According to the website of the Russian magazine GLONASS Messenger, the Russian Federal Space Agency communicated its proposals for specific areas in the United Kingdom (or, more likely, its territories) to accommodate stations of the GLONASS System for Differential Correction and Monitoring (SDCM). Apparently, an offer was made by the deputy head of Roscosmos, Oleg Frolov, in discussions with David Parker, the director of the British Space Agency. The desired locations for the stations will not be disclosed until the approval of their establishment by the British side, the website reported.

    Head Rolls. After repeated satellite launch failures and rumblings about embezzlement and corruption within the Russian space program Roscosmos, Vladimir Popovkin was let go as director and replaced by Oleg Ostapenko, a colonel general in the Russian Military, deputy minister of Defence, and former commander of the Aerospace Defence Forces. The Russian government also announced formation of new agency, the United Rocket and Space Corporation, to manage satellite and rocket manufacturing facilities heretofore supervised by Roscosmos.

  • Ground Control Readied for GPS III

    Raytheon Company reached several milestones recently in its development of the GPS Next -Generation Operational Control System (GPS OCX).  Lockheed Martin’s GPS III Non-flight Satellite Testbed (GNST) — a full-sized, functional satellite prototype currently residing at Cape Canaveral Air Force Station — successfully established remote connectivity and communicated with OCX during pre-flight tests.

    GNST proved that it could connect with and receive commands from Raytheon’s Launch and Check Out System (LCS), a part of OCX that supports the satellite and mitigates risks prior to launch. The GNST received commands from Lockheed Martin’s Launch and Checkout Capability (LCC) node in Newtown, Pennsylvania via the OCX servers at Raytheon’s facility in Aurora, Colorado; the system then returned satellite telemetry to the control station. The tests mirror launch and early orbit testing planned for all flight vehicles.

    “While we have connected OCX with ground-based simulators before, these tests were the first time that OCX and a GPS III satellite have actually communicated,” said Keoki Jackson, vice president for Lockheed Martin’s Navigation Systems mission area.

    Ahead of Schedule. Raytheon received Interim Authorization to Test (IATT) security certification from the U.S. Air Force for OCX LCS four months ahead of schedule. The company received a one-year certification with no liens, meaning the government does not require any changes.

    “Typically, IATT certification is given for six-month increments,” said Matthew Gilligan, Raytheon’s GPS OCX program manager and a vice president in Raytheon’s Intelligence, Information, and Services business. “The LCS one-year accreditation speaks to the quality of the information assurance design and threat protection.” The IATT not only includes the LCS, but also Lockheed Martin’s GPS III satellite support systems, Exercise and Rehearsal Training Tool, and Upload Generation Tool.

    OCX is being developed in two blocks. There are seven iterations in Block 1 and one in Block 2. LCS is the fifth Iteration of Block 1; it successfully completed Critical Design Review in June 2013.

    Early Orbit Exercises. Lockheed Martin and Raytheon also completed the third of five planned launch and early orbit exercises to demonstrate launch readiness of GPS III and OCX.

    Exercise 3 demonstrated space-ground communications; first acquisition and transfer orbit sequences; orbit-raising maneuver planning and execution; and basic anomaly detection and resolution capabilities. In addition, the industry and Air Force GPS Directorate teams jointly executed mission planning activities, such as orbit determination and the generation of upload command files.

    Two additional readiness exercises and six 24/7 launch rehearsals are planned before launch of the first GPS III satellite. The first flight GPS III space vehicle (SV-01) is expected to be available for launch in 2014, and launched by the U.S. Air Force in 2015.

    Exelis Encryptors. Exelis delivered the first three of a planned 14 ground-based encryptors to Raytheon Company for OCX. Designed to automatically code and decode GPS signals, encryptors facilitate the exchange of user information by securely transmitting navigation payload data between the OCX ground station and the orbiting constellation of satellites.

    Delivery followed successful thermal, electromagnetic interference and security verification testing. Exelis provides critical elements of software in the navigation processing subsystem that will enable controllers to better understand the exact position of GPS satellites. This helps ensure accurate navigation information is securely broadcast to users. In addition to encryptors, Exelis is building high-precision receivers for use in GPS ground monitoring stations and satellite signal simulators for testing purposes.

    Exelis is also on contract with Lockheed Martin to provide the payloads for the GPS III satellites.

  • GPS III and OCX Satellite Launch, Early Orbit Ops Successfully Demonstrated

    GPS III and OCX Satellite Launch, Early Orbit Ops Successfully Demonstrated

    Artist's concept of the nextgen GPS III satellite (courtesy of the USAF).
    Artist’s concept of the nextgen GPS III satellite (courtesy of the USAF).

    Lockheed Martin and Raytheon Company successfully completed the third of five planned launch and early orbit exercises to demonstrate the launch readiness of the world’s most powerful and accurate Global Positioning System (GPS), the U.S. Air Force’s next-generation GPS III satellite and Operational Control System (OCX).

    Successful completion of Exercise 3, on August 1, was a key milestone demonstrating Raytheon’s OCX software meets mission requirements and is on track to support the launch of the first GPS III satellite, being produced by Lockheed Martin. Two additional readiness exercises and six 24/7 launch rehearsals are planned before launch of the first GPS III satellite in 2015.

    Using new installments of Raytheon’s OCX software and Lockheed Martin’s GPS III Launch and Checkout Capability (LCC), the Air Force Global Positioning System Directorate and the industry team completed a launch and early orbit exercise over a three-day period in late July. Exercise 3 demonstrated space-ground communications; first acquisition and transfer orbit sequences; orbit-raising maneuver planning and execution; and basic anomaly detection and resolution capabilities. In addition, the industry and customer teams jointly executed mission planning activities, such as orbit determination and the generation of upload command files.

    Exercise 3 expands on two previous exercises, with a longer mission timeline, and the introduction of simulated vehicle and ground anomalies to evaluate the combined response capabilities of the control segment, satellite and operations crew. “Successful completion of Exercise 3 clearly demonstrates that OCX is on track to support the first GPS III satellite launch,” stated Matt Gilligan, a vice president with Raytheon’s Intelligence, Information and Services business and Raytheon’s GPS OCX program manager. “The system responded as designed, and met all of the launch exercise success criteria and successfully demonstrated our anomaly response.”

    “Exercise 3 demonstrated that the cross-organizational operations team is on track to support successful GPS III launch and on-orbit checkout missions from our Newtown facility,” said Keoki Jackson, vice president of Lockheed Martin’s Navigation Systems mission area. “I look forward to the team’s continued success as they progress through the complex mission readiness program towards the first GPS III launch.”

    The Lockheed Martin-developed GPS III satellites and Raytheon‘s OCX are critical elements of the U.S. Air Force’s effort to modernize the GPS enterprise more affordably while improving capabilities to meet the evolving demands of military, commercial and civilian users worldwide.

    GPS III satellites will deliver three times better accuracy; provide up to eight times more powerful anti-jamming capabilities; and include enhancements which extend spacecraft life 25 percent further than the prior GPS block. The GPS III also will carry a new civil signal designed to be interoperable with other international global navigation satellite systems, enhancing civilian user connectivity.  The spacecraft bus and antenna assemblies for the first GPS III satellite have been delivered to Lockheed Martin’s GPS III Processing Facility and are in the integration and test flow leading to the planned space vehicle delivery in mid-2014.

    OCX is being developed in two Blocks using a commercial best practice iterative software development process, with seven iterations in Block 1 and one iteration in Block 2. Exercise 3 was conducted using the recently completed Iteration 1.4 software. Exercise 4, scheduled for early 2014, will use Iteration 1.5 software, which includes the Launch and Checkout System capability as well as all critical information assurance features needed to support launch of the first GPS III satellite.

    The GPS III team is led by the Global Positioning Systems Directorate at the U.S. Air Force Space and Missile Systems Center. Air Force Space Command’s 2nd Space Operations Squadron (2SOPS), based at Schriever Air Force Base, Colorado, manages and operates the GPS constellation for both civil and military users.

  • The System: IRNSS Success, GLONASS Bellyflop

    IRNSS Success

    The Indian Regional Navigation Satellite System (IRNSS) successfully launched its first satellite on July 1 from the Satish Dhawan Space Centre at Sriharikota spaceport on the Bay of Bengal. An Indian-built Polar Satellite Launch Vehicle PSLV-C22, XL version, carried the 1,425-kg satellite aloft.

    IRNSS-1A is the first of seven satellites that will make up the new constellation: four satellites in geosynchronous orbits inclined at 29 degrees, with three more in geostationary orbit. IRNSS-1A is one of the geosynchronous satellites.

    Following launch, the master control facility conducted five orbit maneuvers to position the satellite in its circular inclined geosynchronous orbit (IGSO) with an Equator crossing at 55 degrees east longitude. Reports indicate that orbit-raising maneuvers have been completed, and all the spacecraft subsystems have been evaluated and are functioning normally.

    IRNSS-1A’s drift eastward from 47 degrees east longitude on July 10 was gradually slowed, and the satellite achieved its assigned inclined geosynchronous orbit, with a 55-degree East equator crossing, by July 18. The orbit inclination is 27.03 degrees.

    Payloads. IRNSS-1A carries two types of payloads, navigation and ranging. The navigation payload will operate in L5 band (1176.45 MHz) and S band (2492.028 MHz), using a Rubidium atomic clock. The ranging payload consists of a C-band transponder that facilitates accurate determination of the range of the satellite. IRNSS-1A also carries corner-cube retro-reflectors for laser ranging. Its mission life is 10 years.

    GLONASS Bellyflop

    A Russian Proton-M rocket carrying three GLONASS navigation satellites crashed soon after liftoff on July 2 from Kazakhstan’s Baikonur cosmodrome. About 10 seconds after takeoff at 02:38 UTC, the rocket swerved, began to correct, but then veered in the opposite direction. It then flew horizontally and started to come apart with its engines in full thrust. Making an arc in the air, the rocket plummeted to Earth and exploded on impact close to another launch pad used for Proton commercial launches.

    Despite the loss, GLONASS still has a full operating constellation of 24 satellites.

    The crash was broadcast live across Russia. Fears of a possible toxic fuel leak immediately surfaced following the incident, but no such leak has been confirmed. The rocket was initially carrying more than 600 tons of toxic propellants. No casualties or damage to surroundings structures or the town of Baikonur have been reported.

    The crashed Proton-M rocket employed a DM-03 booster, which was being used for the first time since December 2010, when another Proton-M rocket with the same booster failed to deliver another three GLONASS satellites into orbit, crashing into the Pacific Ocean 1,500 kilometers from Honolulu.

    A Russian government investigation revealed that at least “three of six angular rate sensors [on the booster stage] were installed incorrectly,” to be specific, upside-down. Examination of the wreckage discovered traces of forced, incorrect installation on three sensors. Assembly-line testing at the factory failed to detect the faulty installation.
    Several videos of the crash are viewable online (YouTube).

    First Live Broadcast of GPS CNAV Messages

    By Oliver Montenbruck, Richard B. Langley, and Peter Steigenberger

    Over the past several years, some users of the GPS navigation system have already benefitted from the addition of various new signals in addition to the legacy C/A- and P(Y)-code. With the introduction of the Block IIR-M satellites in 2005, a new civil signal (L2C) was transmitted on the L2 frequency, and a new signal on a new frequency (L5) was introduced as a standard signal with the Block IIF satellites beginning in 2010. These new signals provide direct access to dual-frequency observations and thus enable improved ionospheric corrections for civil, including aeronautical, users. In addition, a new Civil Navigation (CNAV) broadcast message has been defined in the GPS Interface Specifications (IS-GPS-200 and IS-GPS-705).

    This message will be transmitted jointly on the L2C and L5 signals and provides a variety of useful new parameters. Compared to the legacy L1 C/A-code navigation message, the CNAV message also offers an increased flexibility concerning the type, sequence, and repeat rate of specific messages.

    CNAV messages have already been broadcast over the past two years by the Michibiki (QZS-1) satellite of the Japanese Quasi-Zenith Satellite System (QZSS), which shares many aspects of the GPS signal design. In contrast to this, Block IIR-M and IIF GPS satellites have only transmitted dummy messages so far and a fully operational CNAV transmission is only foreseen once the ongoing modernization of the GPS control segment has been completed.

    Triggered by various interest groups, the Global Positioning Systems Directorate has just conducted a first test campaign with live CNAV transmissions on L2C and L5 over the two-week period from June 15 to 29 (see Global Positioning System Modernized Civil Navigation (CNAV) Live-Sky Broadcast Test Plan.) It served as a first opportunity for end users and receiver manufacturers to test the decoding and use of the new messages under a wide range of different configurations.

    CNAV messages have a common length of 300 data bits and are identified by a message type number that signifies their contents. The messages presently defined for GPS are summarized in Table 1. For QZSS, complementary messages have been established, which enable, among other features, a rebroadcast of GPS-specific data to QZSS users.

    Table 1. Summary of CNAV message types transmitted by space vehicles (SVs). Messages marked by an asterisk were transmitted during the recent CNAV test campaign.

    Message

    Type

    CNAV Message Title

    Function/Purpose

    0*

    		 Default Default message (transmitted when no message data is available)

    10*

    		 Ephemeris 1 SV position parameters for the transmitting SV

    11*

    		 Ephemeris 2 SV position parameters for the transmitting SV

    12*

    		 Reduced Almanac Reduced almanac data packets for seven SVs

    13

    		 Clock Differential Correction SV clock differential correction parameters

    14

    		 Ephemeris Differential Correction SV ephemeris differential correction parameters

    15*

    		 Text Text (29 eight-bit ASCII characters)

    30*

    		 Clock, Iono & Group Delay SV clock correction parameters, ionospheric and group delay correction parameters (inter-signal correction parameters)

    31

    		 Clock & Reduced Almanac SV clock correction parameters, reduced almanac data packets for four SVs

    32*

    		 Clock & EOP SV clock correction parameters, Earth orientation parameters; Earth-centered, Earth-fixed to Earth-centered inertial coordinate transformation

    33*

    		 Clock & UTC SV clock correction parameters, Coordinated Universal Time parameters

    34

    		 Clock & Differential Correction SV clock correction parameters, SV clock and ephemeris differential correction parameters

    35*

    		 Clock & GGTO SV clock correction parameters, GPS to GNSS time-offset parameters

    36

    		 Clock & Text SV clock correction parameters, text (18 eight-bit ASCII characters)

    37

    		 Clock & Midi Almanac SV clock correction parameters, midi (mid-accuracy) almanac parameters

    Other than the legacy L1 navigation message, which adheres to a fixed order of subframes, the sequence of CNAV messages can be varied widely to provide users with an optimized set of low latency information and parameters that change infrequently. As a baseline, the two ephemeris message types 10 and 11 are combined with any of the clock-and-auxiliary data messages (types 30 through 37) to provide users with the orbit and clock data of the received satellites. With a transmission duration of 12 seconds per CNAV message on L2C, a minimum of 36 seconds is required to transfer this information to the user if no other messages are transmitted. On L5, which operates at twice the data rate, a new frame is transmitted once every 6 seconds yielding a minimum of 18 seconds for the broadcast of ephemeris and clock data.

    The recent test campaign started at 18:00 GPS Time on Saturday, June 15, 2013, with the transmission of message types 10, 11, 15, and 30 on a first space vehicle (PRN24) and included PRN12 from 18:42 onwards. Other space vehicles were sequentially phased in until all active IIR-M and IIF satellites (except for the recently launched IIF-4 satellite) transmitted CNAV on the supported signals. When the test ended exactly two weeks later (June 29, 18:00 GPST), all participating satellites were transmitting a complex master frame of 15 x 4 = 60 individual messages, which was repeated once every 12 minutes (on L2C). Each minor frame comprised the two ephemeris messages and at least one clock-data message (see Table 2).

    Table 2. Sequence of message types in a CNAV master frame.

    Message Types

    10

    11

    15

    30

    10

    11

    32

    33

    10

    11

    12

    35

    10

    11

    12

    30

    10

    11

    12

    33

    10

    11

    12

    35

    10

    11

    12

    30

    10

    11

    32

    33

    10

    11

    15

    35

    10

    11

    32

    30

    10

    11

    12

    33

    10

    11

    12

    35

    10

    11

    12

    30

    10

    11

    12

    33

    10

    11

    12

    35

    Other messages included a reduced almanac (message type 12) and a text message (message type 15) with dummy content (“THIS IS A GPS TEST MESSAGE.”)

    The CNAV data were recorded by selected multi-GNSS monitoring stations of the German Aerospace Establishment (Deutsches Zentrum für Luft- und Raumfahrt or DLR) and the University of New Brunswick (UNB), which were specifically configured to record raw GPS navigation frames in addition to the normal observation data. The stations are located at Singapore (SIN0); Sydney, Australia (UNX2); Maui, U.S.A. (MAO0); and Hartebeesthoek, South Africa (HRAG); as well as Fredericton, Canada (UNB) and are equipped with either Javad Delta-G2/G3TH or NovAtel OEM6 receivers. Following initial validation, the raw and decoded data from the CNAV test will be made available to interested users through the Multi-GNSS Experiment (MGEX) of the International GNSS Service (see http:/igs.org/mgex/) to facilitate the development of user software and suitable data formats (such as an extended RINEX navigation message format).

    The CNAV orbit and clock data were updated once every two hours and offer a slightly higher bit resolution than their legacy counterparts. However, the accuracy of the ephemeris data has not yet been evaluated nor compared to that of the L1 C/A-code navigation data.

    As indicated above, the CNAV data can also provide a particularly compact form of almanac data known as the reduced almanac. It does not offer clock information (that is not normally required for a signal search) and assumes a circular orbit, which reduces the overall accuracy. Still, it can be transmitted (and repeated) in a much shorter time interval than the legacy almanac, which requires a total of 12.5 minutes. Each reduced almanac message (message type 12) provides orbit information for a total of seven satellites and it takes a set of five such messages to convey information for a complete constellation. For the master frame layout described above, the full constellation reduced almanac is repeated twice within 12 minutes on L2C (and half this time on L5).

    Novel types of CNAV data not covered by the legacy navigation message include the differential code biases (also known as inter-system corrections or ISCs), which are required for pseudorange-based positioning with signals other than the legacy P(Y)-code (in addition to the established Timing Group Delay parameter or TGD). An overview of TGD and ISC values broadcast by the various satellites participating in the CNAV test is given in Table 3.

    Table 3. Differential code biases (in nanoseconds) of GPS Block IIR-M and IIF satellites broadcast during the test campaign as part of the message type 30 CNAV messages.

    SV Type

    SVN

    PRN

    TGO

    ISC L1CA

    ISC L2C

    ISC L5I5

    ISC L5Q5

    IIR-M

    48

    07

    -10.71

    -0.84

    6.52

    IIR-M

    50

    05

    -10.24

    -0.32

    5.41

    IIR-M

    52

    31

    -13.04

    -0.55

    7.36

    IIR-M

    53

    17

    -10.24

    -0.84

    6.17

    IIR-M

    55

    15

    -10.24

    -0.47

    5.62

    IIR-M

    57

    29

    -9.31

    -0.76

    5.06

    IIR-M

    58

    12

    -12.11

    -0.76

    6.64

    IIF

    62

    25

    5.59

    -2.07

    -5.24

    -0.38

    -0.87

    IIF

    63

    01

    8.38

    -2.30

    -7.57

    0.38

    2.15

    IIF

    65

    24

    2.79

    -0.26

    -2.27

    2.27

    3.70

    Another important achievement is the provision of Earth orientation parameters (EOP) in message 32, which provides GPS users with access to the celestial reference frame. EOPs were transmitted during the second test week and updated on a daily basis (see Table 4). Knowledge of these parameters is of particular interest for GPS-based orbit determination and navigation of spacecraft (in low Earth orbit), which is preferably referred to an inertial rather than an Earth-fixed coordinate system.

    Table 4. Daily Earth orientation parameters from the CNAV test campaign (pole coordinates and dUT1 (UT1-UTC) time differences and derivatives).

    Epoch (GPST)

    x_p

    (arcseconds)

    x_p_dot

    (arcseconds per day)

    y_p

    (arcseconds)

    y_p_dot

    (arcseconds per day)

    dUT1

    (seconds)

    dUT1_dot

    (seconds per day)

    June 22, 0:00

    0.13517

    0.00104

    0.39657

    -0.00054

    0.06341

    -0.00046

    June 23, 0:00

    0.13621

    0.00102

    0.39604

    -0.00056

    0.06295

    -0.00049

    June 24, 0:00

    0.13740

    0.00101

    0.39535

    -0.00058

    0.06231

    -0.00053

    June 25, 0:00

    0.13815

    0.00099

    0.39487

    -0.00060

    0.06164

    -0.00063

    June 26, 0:00

    0.13846

    0.00096

    0.39443

    -0.00062

    0.06078

    -0.00067

    June 27, 0:00

    0.13885

    0.00094

    0.39381

    -0.00064

    0.06004

    -0.00067

    June 28, 0:00

    0.13947

    0.00093

    0.39310

    -0.00066

    0.05909

    -0.00063

    June 29, 0:00

    0.13987

    0.00090

    0.39246

    -0.00068

    0.05842

    -0.00053

    Overall, CNAV offers exciting prospects for improved GPS utilization and users may look forward to the next test campaigns, which will tentatively be conducted once every six months.

    As a side note, it should be mentioned that individual satellites could be observed to transmit various types of non-standard CNAV messages as well as CNAV messages with improper data (such as an invalid week count) after the end of the main test campaign. Various receivers in the MGEX network, which were processing the received CNAV messages internally and which put full confidence in their proper contents, were mislead by such information. During the actual test campaign, all data appeared fully valid and no problems were reported by the stations.

    OLIVER MONTENBRUCK is the head of the GNSS Technology and Navigation Group at DLR’s German Space Operations Center in Oberpfaffenhofen, Germany.

    RICHARD B. LANGLEY is a professor in the Department of Geodesy and Geomatics Engineering at the University of New Brunswick, Fredericton, New Brunswick, Canada.

    PETER STEIGENBERGER is a staff member in the Institut für Astronomische und Physikalische Geodäsie of the Technische Universität München (TUM) in Munich, Germany.

  • Lockheed Martin Delivers Antenna Assemblies for First GPS III Satellite

    Lockheed Martin has completed and is preparing to install the navigation, communication, and hosted payload antenna assemblies for the first satellite of the next-generation GPS III.

    Seven antenna assemblies, produced at Lockheed Martin’s Newtown, Pennsylania, facility were delivered to the company’s GPS III Processing Facility (GPF) near Denver, Colorado, on June 14.  The antennas will be installed on the first GPS III space vehicle (SV01), which Lockheed Martin will deliver to the U.S. Air Force on schedule, “flight-ready,” in 2014.

    The new antennas for GPS III SV01 will provide the satellite’s capability to send and/or receive data for Earth-coverage and military Earth-coverage navigation; a UHF crosslink for inter-satellite data transfer; telemetry, tracking and control for satellite-ground communications; and data acquisition and communication for the nuclear detection system hosted payload. The antenna designs enable three to eight times greater anti-jamming signal power to be broadcast to military users across the globe when compared to previous GPS generations.

    “These antennas on the next generation of GPS III satellites will transmit data utilized by more than one billion users with navigation, positioning and timing needs,” explained Keoki Jackson, vice president of Lockheed Martin’s Navigation Systems mission area. “We have become reliant on GPS for providing signals that affect everything from cell phones and wristwatches, to shipping containers and commercial air traffic, to ATMs and financial transactions worldwide.”

    GPS III is a critically important program for the Air Force, affordably replacing aging GPS satellites in orbit, while improving capability to meet the evolving demands of military, commercial and civilian users. GPS III satellites will deliver three times better accuracy, include enhancements which extend spacecraft life 25 percent further than the prior GPS block, and a new civil signal designed to be interoperable with international global navigation satellite systems.

    The production of the first GPS III satellite continues on schedule. Recent testing of the SV 01 bus — the portion of the space vehicle that carries mission payloads and hosts them in orbit — assured that all bus subsystems are functioning normally and that they are ready for final integration with the satellite’s navigation payload.
    This milestone follows February’s successful initial power on of the SV01 spacecraft bus, which demonstrated  the electrical-mechanical integration, validated the satellite’s interfaces and led the way for functional electrical hardware-software integration testing.

    Lockheed Martin is under contract for production of the first four GPS III satellites (SV01-04), and has received advanced procurement funding for long-lead components for the fifth, sixth, seventh and eighth satellites (SV05-08).

    The GPS III team is led by the Global Positioning Systems Directorate at the U.S. Air Force Space and Missile Systems Center. Lockheed Martin is the GPS III prime contractor with teammates ITT Exelis, General Dynamics, Infinity Systems Engineering, Honeywell, ATK and other subcontractors. Air Force Space Command’s 2nd Space Operations Squadron (2SOPS), based at Schriever Air Force Base, Colorado, manages and operates the GPS constellation for both civil and military users.

  • Lockheed Martin GPS III Prototype Validates Test Facilities

    Lockheed Martin GPS III Prototype Validates Test Facilities

    Lockheed Martin’s GPS III Non-Flight Satellite Testbed (GNST) has successfully completed a series of high-fidelity pathfinding events which validate the process and facility for vehicle integration checkout, as well as signals interference testing, that the next-generation satellites of GPS III will go through before delivery for launch.

    An innovative investment by U.S. Air Force under the original GPS III development contract, the GNST is a full-sized GPS III satellite prototype which has helped to identify and resolve development issues prior to integration and test of the first GPS III space vehicle (SV 1). Following the Air Force’s rigorous “back-to-basics” acquisition approach, the GNST has gone through the development, test and production process for the GPS III program first, significantly reducing risk for the flight vehicles, improving production predictability, increasing mission assurance and lowering overall program costs.

    During this latest milestone, the GNST successfully completed thermal vacuum (T-Vac) chamber trail blazing, demonstrating facility, mechanical and electrical ground equipment integration, and ran a series of vehicle integration test procedures. The GNST also completed Passive Intermodulation (PIM) and Electromagnetic Compatibility (EMC) testing, which assures that multiple high-powered signals generated from the satellite’s navigation downlink transmissions, or transmitted from the hosted nuclear detection system payload on the satellite, do not interfere with each other or themselves.

    “As the GNST serves as a pathfinder for the GPS III program, its successful completion of this testing validates that development risks have been retired and our engineering and technology is sound for the flight vehicles being built,” explained Keoki Jackson, vice president for Lockheed Martin’s Navigation Systems mission area.

    The GNST is now being prepared for shipment to Cape Canaveral U.S. Air Force Station, Florida, for more risk reduction activities related to satellite launch.

    The GPS III prototype in an anechoic chamber where it completed Passive Intermodulation (PIM) and Electromagnetic Compatibility (EMC) testing at Lockheed Martin’s GPS III Processing Facility outside of Denver, Colorado. Photo: Lockheed Martin’s Navigation Systems
    The GPS III prototype in an anechoic chamber where it completed Passive Intermodulation (PIM) and Electromagnetic Compatibility (EMC) testing at Lockheed Martin’s GPS III Processing Facility outside of Denver, Colorado. Photo: Lockheed Martin’s Navigation Systems

    GPS III is a critically important program for the Air Force, affordably replacing aging GPS satellites in orbit, while improving capability to meet the evolving demands of military, commercial and civilian users. GPS III satellites will deliver three times better accuracy and — to outpace growing global threats that could disrupt GPS service — up to eight times improved anti-jamming signal power for additional resiliency. The GPS III will also include enhancements adding to the spacecraft’s design life and a new civil signal designed to be interoperable with international global navigation satellite systems.

    Lockheed Martin is currently under contract for production of the first four GPS III satellites (SV 1-4), and has receivedadvanced procurement funding for long-lead components for the fifth, sixth, seventh and eighth satellites (SV 5-8).

    The Lockheed Martin team remains on track to deliver the first GPS III satellite, with its enhanced capabilities over current orbiting systems, for launch availability in 2014.

    The GPS III team is led by the Global Positioning Systems Directorateat the U.S. Air Force Space and Missile Systems Center. Lockheed Martin is the GPS III prime contractor with teammates ITT Exelis, General Dynamics, Infinity Systems Engineering, Honeywell, ATK and other subcontractors. Air Force Space Command’s 2nd Space Operations Squadron (2SOPS), based at Schriever Air Force Base, Colorado, manages and operates the GPS constellation for both civil and military users.

  • U.S. Navy Conducts Anti-Jam Tests

    In July, the Communications and GPS Navigation Program Office mounted a Small Antenna System on an Aerostar unmanned aircraft, then placed the small UAV in a room lined with signal-absorbent material, where it was subjected to GPS jamming signals. Read more about the tests here.

     

  • Lockheed Martin Completes Functional Testing of GPS III Electronic Systems

    A Lockheed Martin-led industry team has completed successful functional integration tests of the spacecraft bus and network communications equipment on the first satellite of the next generation Global Positioning System, known as GPS III.

    The recent testing of GPS III space vehicle 1 (SV 1) bus — the portion of the space vehicle that carries mission payloads and hosts them in orbit — assured that all bus subsystems are functioning normally and ready for final integration with the satellite’s navigation payload. Systems tested included: guidance, navigation and control; command and data handling; on-board computer and flight software; environmental controls; and electrical power regulation. The SV 1 satellite’s network communication equipment subsystem that interfaces with the ground control segment and distributes data throughout the space vehicle also passed all tests as expected.

    This milestone follows February’s successful initial power-on of SV 1, which demonstrated the electrical-mechanical integration, validated the satellite’s interfaces, and led the way for functional and hardware-software integration testing.

    “The successful completion of the SV 1 bus functional check out validates that the spacecraft is now ready to begin the next sequence of payload integration and environmental testing, prior to delivery,” explained Keoki Jackson, vice president of Lockheed Martin’s Navigation Systems mission area.

    GPS III SV 1’s navigation payload, which is being produced by ITT Exelis, will be delivered to Lockheed Martin’s GPS Processing Facility (GPF) near Denver later in 2013. The hosted nuclear detection system payload has already been delivered and mechanically integrated. The satellite remains on schedule for flight-ready delivery to the U.S. Air Force in 2014.

    GPS III is a critically important program for the Air Force, affordably replacing aging GPS satellites in orbit, while improving capability to meet the evolving demands of military, commercial and civilian users. GPS III satellites will deliver three times better accuracy and — to outpace growing global threats that could disrupt GPS service — up to eight times improved anti-jamming signal power for additional resiliency. The GPS III will also include enhancements adding to the spacecraft’s design life and a new civil signal designed to be interoperable with international global navigation satellite systems.

    The U.S. Air Force has produced a video about the GPS satellite modernization program:

    Lockheed Martin is under contract for production of the first four GPS III satellites (SV 1-4), and has received advanced procurement funding for long-lead components for the fifth, sixth, seventh and eighth satellites (SV 5-8).

    The GPS III team is led by the Global Positioning Systems Directorate at the U.S. Air Force Space and Missile Systems Center. Lockheed Martin is the GPS III prime contractor with teammates ITT Exelis, General Dynamics, Infinity Systems Engineering, Honeywell, ATK and other subcontractors. Air Force Space Command’s 2nd Space Operations Squadron (2SOPS), based at Schriever Air Force Base, Colo., manages and operates the GPS constellation for both civil and military users.

    Headquartered in Bethesda, Maryland, Lockheed Martin is a global security and aerospace company that employs about 118,000 people worldwide and is principally engaged in the research, design, development, manufacture, integration, and sustainment of advanced technology systems, products, and services. The corporation’s net sales for 2012 were $47.2 billion.

  • The System: Galileo Leaves the Building

    In the early hours of May 15, Galileo’s first full operational capability (FOC) satellite left manufacturer OHB System AG’s integration hall in Bremen, Germany, after successfully completing integration and system testing. Later that same day, it arrived by road at the European Space Agency’s (ESA’s) technical center at Noordwijk in the Netherlands for a rigorous set of tests to check its readiness for launch. The tests will simulate different aspects of launch and space environment. The comprehensive test program will validate the new design and all the FOC satellites to follow.

    This first FOC satellite is functionally identical to the first four in-orbit validation (IOV) satellites already in orbit, but has been built by a separate industrial team. Like the other 21 FOC satellites so far procured by ESA, the satellite’s prime contractor is OHB System AG, and the navigation payload was produced by Surrey Satellite Technology Ltd. in Guildford, UK.

    Thermal vacuum testing at the European Space Research and Technology Centre (ESTEC) will simulate temperature extremes the satellites must endure in the airlessness of space throughout their 12-year working lifetimes. Without any moderating atmosphere, temperatures can shift hundreds of degrees from sunlight to shadow.

    Other activities on the schedule include shaker and acoustic noise testing — simulating the vibration and noise of launch — as well as electromagnetic compatibility and antenna testing, placing the satellite in chambers shielded from all external radio signals to reproduce infinite space and check that its various antennas and electrical systems are interoperable without harmful interference.

    “The Galileo FOC satellites provide the same capabilities as the previous IOV satellites, but with improved performance, such as higher transmit power,” explained Giuliano Gatti, the head of the Galileo Space Segment Procurement Office. “They are to all intents a new design that requires a full checkout before getting the green light for launch.”

    The second FOC flight model is due to arrive at ESTEC in early June, and the third in the middle of July. The first two satellites are to be placed in orbit on board a Soyuz launcher, with a scheduled lift-off from Kourou in French Guyana this fall, with two more due to follow by the end of the year.

    The first four Galileo IOV satellites, launched in 2011 and 2012, were provided by EADS Astrium with Thales Alenia Space Italy responsible for integrating the satellites and Astrium in Portsmouth, UK, providing the navigation payloads. They provided their first navigation fix in March 2013.

    The definition, development and in-orbit validation phases of the Galileo programme are being carried out by ESA and co-funded with the European Commission (EC).

    The subsequent FOC phase is managed and funded by the EC. The commission has delegated the role of design and procurement agent to ESA for the FOC phase. At the same time as the satellites are being assembled on a production-line basis, ground stations are also being established on European territories around the globe.

    Photo credit: Pat Corkery, United Launch Alliance.
    Photo credit: Pat Corkery, United Launch Alliance.

    GPS Leaves This Earth

    A t 5:38 p.m. Eastern Daylight Time (21:38 UTC) on May 15,  the fourth GPS IIF satellite, Space Vehicle Number (SVN) 66 built by Boeing, ascended towards orbit aboard a United Launch Alliance Atlas V rocket at from Cape Canaveral Air Force Station, Florida.

    “The GPS constellation remains healthy and continues to meet and exceed the performance standards to which the satellites were built. Our goal is to deliver sustained, reliable GPS capabilities to America’s warfighters, our allies, and civil users around the world, and this is done by maintaining GPS performance, fielding new capabilities and developing more robust modernized capabilities for the future,” said Colonel Bernie Gruber, director of the U.S. Air Force Space and Missile Systems Center’s GPS Directorate.

    The new capabilities of the IIF satellites will provide greater navigational accuracy through improvements in atomic clock technology; a more robust signal for commercial aviation and safety-of-life applications, known as the new third civil signal (L5); and a 12-year design life providing long-term service. These upgrades deliver improved anti-jam capabilities for warfighters and improved security for military and civil users around the world, the Air Force said in a statement.

    The IIF-4 satellite is expected to complete testing in August, after which it will be utilized as a reserve or backup satellite. It becomes the fourth satellite in a 12-strong network of GPS IIF spacecraft manufactured by Boeing as lead contractor, the first of which was boosted into orbit in May 2010. The Air Force expects the first of the next-generation GPS IIIA satellites to enter service sometime in 2014.

    System Briefs

    GLONASS. The GLONASS 747 M-series satellite launched on April 26 has maneuvered into an orbital slot near GLONASS 728, the operational satellite in Plane 1, slot 2. 747 will presumably serve as a reserve until it replaces 728, unless another Plane 1 satellite expires first. The next Russian launch, a GLONASS-M trio, is scheduled for July 1. There are currently 24 operational GLONASS satellites.

    IRNSS. The first Indian Regional Navigation Satellite System satellite is expected to rise at the end of June. The IRNSS plans to orbit of seven: three geostationary and four geosynchronous, providing regional coverage via navigation signals in the L5 and S bands.

  • GPS OCX Ground Control in GAO Report

    A March 2013 report from the Government Accountability Office (GAO) seems to claim that the projected cost of the next-generation GPS ground-control system, known as OCX, increased by 43 percent, or $1 billion over the past year, to a total cost estimate of $3.7 billion. As GPS World contributing editor Don Jewell wrote shortly after the GAO release, “In fact, the report does not actually say that exactly, but you have to dig deep to determine that. Most readers won’t take the time to do that and will assume that the OCX program is grossly over budget. It is not.” A Raytheon spokesperson pointed out that the basis for the program cost estimate goes far beyond the scope of the original 2010 Raytheon prime contract of $886.4 million, and that the current value of the company’s contract is $969 million.

    Design requirements for OCX call for it to support the GPS III constellation’s stringent accuracy, anti-jam, and information assurance requirements. The system is also to be backward-compatible with current GPS satellites. The original contracted carried an initial delivery date of 2016. At least some of the government-specified revisions in the contract come in the context of the need for absolute information assurance, given the Internet- and associated computer program-hacking by foreign sources, considered alongside  the vast user base supplied by GPS, including the U.S. military’s reliance on its capability for many functions.

    Kevin Ramundo, Vice President for Communications, Raytheon Intelligence, Information and Services, commented:

    “GPS modernization through the launch of GPS III satellites and the GPS OCX ground system will provide new mission-critical capabilities to war fighters and additional capacity to meet the needs of millions of additional GPS users each year.

    “Since the initial contract award, Raytheon’s GPS OCX program has made considerable progress including Milestone B approval and the successful completion of two ground station/satellite integration exercises. Nearly 50 percent of the software development is complete.

    “With regard to the GAO report, it is important to note that the basis for their program cost estimate goes far beyond the scope of the Raytheon contract. In 2010, the contract award to Raytheon for GPS OCX was $886 million. The current value of our contract is $969 million, which now includes additional scope such as launch and check-out capability, tech baseline, and special studies.”

    In December 2012, Col. Bernie Gruber of the U.S. Air Force GPS Directorate wrote in the pages of GPS World what was the commonly accepted perception of and public government position on OCX:

    “Along with a host of additional satellite capabilities and signals, we will correspondingly modernize our ground segment. Our Next-Generation Operational Control System (OCX) is designed to command and control our modernized secondary civil signal L2C, safety-of-life signal L5, and the internationally compatible signal L1C.  . . . . . As the modernized signals become operational, users will see faster signal acquisition, enhanced reliability, and a greater operating range. The information assurance, expandability, and service-oriented architecture will afford users and operators with security and information they simply don’t have today.”

    The View from 2013. The 190-page GAO report, “Defense Acquisitions: Assessments of Selected Weapon Programs,” states that the scope and complexity of key OCX program elements was underestimated, and alluded to overruns that have historically beset Pentagon space programs.

    Two of the 190 pages in the report (click here for highlights and to download the full PDF)

    specifically address OCX, which is identified as one of 19 weapons “Programs That Entered Development with Technologies Fully Mature or Nearing Maturity” and one of 14 “Programs with technologies nearing maturity at knowledge point 1 date.” OCX is given a knowledge point 1 date of November 2012.

    According to the Report, “Air Force officials recently stated that, although GPS III is still maintaining an April 2014 “available for launch” date for the first satellite, the planned launch date is being moved to May 2015 in order to synchronize it with the availability of the GPS Operational Control Segment (OCX) Block 0, without which the satellites cannot be launched and checked out.”

    “The program has experienced significant requirements instability and schedule delays while in technology development,” the report reads. “The contractor initially underestimated the scope and complexity of the necessary information assurance requirements which required additional personnel with the necessary expertise and increased government management.”

    Changes in Specifications. In June 2012, a Raytheon executive stated that the OCX contract had been significantly modified, with the addition of a launch and checkout capability that had previously been the responsibility of Boeing, prime contractor on the GPS IIF satellites.

    He also identified information assurance, a primary OCX requirement, as “a big challenge. It is very important that we protect this system against the current and evolving cyber threats because they are real and the nation can’t afford to have this system compromised.”

    An Update Last Autumn. In a November 2012 conversation with GPS World defense editor Don Jewell, Raytheon VP and Program Manager for OCX Ray Kolibaba made the following remarks:

    “We currently have 450 people at Raytheon working OCX, and with our subs, an additional 300 personnel. Altogether we have 750 personnel working GPS and OCX issues. This does not include the military and civilian personnel at Air Force Space Command and Space and Missile Systems Center.”

    [ . . . . ]

    Kolibaba-W
    Headshot: Ray Kolibaba

    “Basically we are nearly on cost for the OCX contract. The current contract value is $925M; the original cost estimate was $886M. We are driving forward on that and the Block 1 date or Ready to Operate (RTO) date. Right now, the customer team is working on finalizing a new enterprise schedule that will show the Program Management Directive dates. So, we don’t know the exact date the government envisions. I expect an official date either late this year or early next year. I encourage you to ask Colonel Gruber [U.S. Air Force GPS Directorate] this question, and maybe then we will also get an answer. We have given them our recommendations.

    “Concerning sequestration, I am not worried. I believe we have a reasonable level of support from Congress to maintain and continue OCX. That doesn’t mean something won’t change. Our Washington folks tell us that OCX appears to be on solid footing. The Air Force FY13 Research, Development, Test & Evaluation budget request for OCX, to include Raytheon, support contractors, the GPS Directorate, Federally Funded Research and Development Centers and the like, was $371.6M, and the Continuing Resolution amount was $369.4M — given the current budget environment, that is strong Congressional support.”

    [ . . . . . ]

    “Successful completion of OCX will make a huge difference on a number of fronts. For instance, even though the FAA and DOT don’t have a whole lot of funding to ante up, we are going to make a difference in how they operate in the future. Some actions are transparent, but not all, as we implement their requirements and as we move forward with OCX.

    “The sooner we implement the true capabilities of GPS on airliners and stop adhering only to the fixed air routes, the sooner we will start saving time and money with a vastly more efficient and flexible air routing system.

    “So, from the civil side, there is certainly a difference, and when we bring other signals in they will be key for us, such as L2C, L5, and L1C. We have the solutions to do that with our receivers at this point in time, and I think it is fairly low-risk. Indeed that is probably another of my unofficial milestones.

    “[On] the navigation side, GPS accuracy will noticeably improve, and we will use a new Kalman Filter. We are working the new Kalman filter with ITT Exelis and JPL to enhance capabilities. Couple that with better information assurance, increased integrity and predictability, along with system safety, and you have many of the key differences in the OCS system going forward.

    [  . . . . . . ]

    “We are required to support 40 PRNs at a minimum, with growth potential to 63 PRNs, and we may be able to support more. I’m not sure there is a limit on the system as such.”

    In April of this year, Don Jewell wrote in his Defense PNT e-newsletter column:

    “Most readers [of the report] won’t take the time to [dig deep]  and will assume that the OCX program is grossly over budget. It is not. In fact, to reach that extraordinary number, OCX cost overruns would need to have grown by 43 percent for each year since it was awarded, and that is ludicrous. According to Raytheon VP and OCX Program Manager Ray Kolibaba, the $3.695 billion number probably comes from including “…programmatic costs beyond OCX development costs and pessimistic projections from the government” that in my experience no acquisition agency, nor Congress for that matter, would ever include when determining true program cost adherence parameters.

    Jewell makes the further point that OCX has grown in scope and schedule due in part to government change requests, mainly in the cyber and information assurance areas.

    Where It Stands Now. Notwithstanding the optimism of the Raytheon OCX program manager six months ago, it is reasonable to expect that the GAO estimate of increased cost has drawn Congressional attention, and that in the current fiscal climate, the entire program may once again be imperiled.

     

  • Update: GPS IIF-4 Successfully Launched from Cape Canaveral

    Update: GPS IIF-4 Successfully Launched from Cape Canaveral

    UPDATE, May 24, by Richard Langley: The Centaur upper stage with the payload still attached was photographed from Tavistock, Devon, in the U.K. by Andy Smith. As can be seen from the ground trace figure in an earlier GPS World news item, the Centaur passed over the U.K. following MECO1, the first main engine cutoff. From Europe, the Centaur could be easily seen by reflected sunlight against the background stars. Its maximum (apparent) brightness magnitude has been estimated as -1 or -2. (Sirius, the brightest star in the night sky, has a magnitude of -1.5; Betelgeuse in the constellation Orion has a mean magnitude of about 0.4; and the limiting visual magnitude for the unaided eye is about 6.)

    Smith’s photograph was taken at 21:58:38 UTC (start) with a Canon EOS 450D Digital Rebel camera with an 18-55mm zoom lens. The camera settings were: focal length 55mm, aperture f/5.6, and an exposure of 8 seconds at an ISO value of 1600. Two images are shown below: the original, as obtained from the camera, and a greyscale image with edge enhancement.

    The Centaur can be seen traveling left to right and starts its track as it crosses the constellation of Cygnus. There’s a slight wobble at the beginning as the shutter release was pressed. The glow at the bottom of the frame is from a streetlight. The elevation angle of the Centaur was approximately 12 degrees.

    SVN66 will operate as PRN27 and it will eventually occupy the C-2 orbital slot, replacing SVN33/PRN03, a Block IIA satellite launched in 1996. SVN66 is currently in a drift orbit about 400 kilometers above the operational constellation. It should reach the C-2 slot within a few days from now. The satellite has already been added to the broadcast almanac although it has not yet started to transmit standard signals. It is currently marked as unhealthy in the almanac and will remain so, even after standard signals are switched on, until testing is completed sometime this summer.

    Centaur upper stage with the payload still attached. Photo credit: Andy Smith
    Centaur upper stage with the payload still attached, original photo. Photo credit: Andy Smith

    The same photo digitally enhanced:

    Photo credit: Andy Smith
    Digitally enhanced photo. Photo credit: Andy Smith
    Photo credit: Pat Corkery, United Launch Alliance.
    Photo credit: Pat Corkery, United Launch Alliance.

    A U.S. Air Force Global Positioning System satellite built by Boeing was successfully launched May 15. The fourth GPS IIF satellite, Space Vehicle Number (SVN) 66, was carried aboard a United Launch Alliance Atlas V Launch Vehicle at 5:38 p.m. EDT (21:38 UTC) May 15 from Cape Canaveral Air Force Station, Florida.

    The new capabilities of the IIF satellites will provide greater navigational accuracy through improvements in atomic clock technology; a more robust signal for commercial aviation and safety-of-life applications, known as the new third civil signal (L5); and a 12-year design life providing long-term service. These upgrades improved anti-jam capabilities for the warfighter and improved security for military and civil users around the world, the Air Force said in a statement.

    The Atlas rocket took off on schedule. The satellite was released from the Centaur upper stage at T+ 3 hours, 23 minutes and 52.8 seconds or about 01:02 UTC on May 16. Details on the Block IIF satellites and the Atlas rocket can be found here.

    “I’m extremely pleased with today’s launch and delighted to be part of this mission that enhances our nation’s critical GPS capability. Thanks to the superb efforts of the of the 45th and 50th Space Wings, United Launch Alliance, our industry partners, the Atlas V and GPS IIF launch teams, the GPS IIF-4 mission was successfully carried out,” said Col. Bernie Gruber, director of the Space and Missile Systems Center’s Global Positioning Systems Directorate.

    “The GPS constellation remains healthy and continues to meet and exceed the performance standards to which the satellites were built. Our goal is to deliver sustained, reliable GPS capabilities to America’s warfighters, our allies and civil users around the world, and this is done by maintaining GPS performance, fielding new capabilities and developing more robust modernized capabilities for the future,” said Colonel Gruber.

    Here are videos of the launch:


    Opening photo by Pat Corkery, United Launch Alliance.

    Photos show the launch of the U.S. Air Force’s GPS IIF-4 satellite from the Kennedy Space Center and Cape Canaveral Air Force Station.