Date: Wed, 15 Oct 2003 15:23:06 -0700 From: Doug Hogarth Subject: Suggestions for Javad receiver operators Upon reviewing Dr Schaer's messages such as May 8th, I believe that operators of Javad receivers may benefit from tips such as those below. Please note that I am not an employee of Javad, and if you have a support relationship with dealer or someone such as TPS then you might follow their advise on such issues. A reason for sending this message now because of the upcoming launches of multiple GPS and GLONASS satellites during the next couple months. Dr Schaer has said that analysis centers can benefit when receivers such as Javad are tracking newly launched or unhealthy satellites. Such raw data can be recorded using settings described below (negative elevation mask and "/par/lock/notvis,on"). First, there are firmware revisions available which are newer than some IGLOS stations are using. Some bugs may have been fixed in such firmware even when not specifically detailed in the release notes (notes typically focus on new/changed features). Loading new firmware is usually not difficult, as long as you know your specific receiver model, have a Windows PC connected by serial port, and can repeat any non-default settings that you might have made. Be advised that there are sometimes some version dependencies if you are using PC-CDU software for settings, download, etc. Details of new firmware and PC-CDU can be found in appropriate download sections of Javad's web site (or TPS if you deal with them). Remember that during the update process NVRAM can and/or should be cleared, so note your non-default settings beforehand and restore them afterward. Firmware 2.3p2 or 2.3p1 or 2.3 (from mid-2003 or late-2002) or 2.2p3 (from mid-2002) is generally considered current. Unless you have specific reason to be running older firmware 2.1 (mid-2000) then you should consider upgrading (there should be no fee for the user-installable firmware). For reference, 2.2 was released mid-2001. Revisions beyond firmware 2.3p2 are probably in the works. For example there could be a setting allowing logging from new/unhealthy satellites without requiring negative elevation mask. Second, Javad's receivers have various settings which can be changed from the default. PC-CDU provides an interface to many such settings, and methods to save such settings to a script for later restore (which is useful before/after the firmware update process). You can specify settings such as elevation masks, etc. PC-CDU also has a menu for Manual mode which allows you a sort of terminal interface to type manual commands from the GRIL documentation which may not have a counterpart elsewhere in PC-CDU. Some non-default settings you might review are the elevation mask and a manual command /par/lock/notvis,on. For users of firmware 2.3p2 or earlier, lowering the mask to -1 can allow data from satellites which have unknown elevation (typically new or flagged unhealthy, but also the rare cases of <4 satellites such as a receiver just starting up). There are multiple places where a mask can be set, so make sure you know the one appropriate to your logging method or set them all. Unless you have heavy processor load such as faster than 1Hz, RTK, etc. you might consider issuing the manual command set,/par/lock/notvis,on. Without such command, channels will only search for satellites known to be above the elevation mask (so again it is useful for brand new satellites, however it does increase processor load). Third, be aware that updates are sometimes released for JPS2RIN or similar program for converting to RINEX. Look at appropriate section of the web site; for example you might find JPS2RIN 1.36 from March 2003. This version may include bug fixes and useful new features such as optional switch -S to create S1 S2 observables (desirable for data you submit to IGS). (For fans of using teqc for conversion to RINEX, a future release of teqc should allow such conversion from .jps files.) If you have questions, please feel free to email me (I've been a Javad user since their beginning). However, I should not take the place of any formal support mechanism (especially if you have some existing relationship). Comments about non-default tracking settings you've tried are also welcome (for example with my good external frequency standard I try 4Hz PLL).