0. What is going on with the navigation (n) file? My software says it can't compute a position due to missing nav file(s)?

1. Why doesn't gzip386.exe work correctly on an IBM PC or compatible when trying to uncompress files created by gzip, UNIX compress or pack?

2. Why do the utility programs downloaded from the directory cors/utilities on the CORS file server not work on the receiving machine?

3. The position file for site SSSS is not available. When will the positions be available to the public ?

4. How do I get CORS data ?

5. Can I use PKUNZIP to uncompress the CORS data ?

6. What does the extension ".gz" mean at the end of the data files ?

7. Where do you store the US Coast Guard DGPS correctors ?

8. The data I want are not available on the CORS file server. What do I do ?

9. I downloaded CORS data but it does not work with my reduction software. What is wrong with the data ?

10. I used your data with my reduction software and my positions are 30 meters (100 feet, 100 m, etc.) different from yours. What is wrong with your position ?

11. Where do I get the NGS precise orbits ?

12. How do I receive your CORS Newsletter on a weekly basis ?

13. Will RINEX-2 data work with my reduction software ?

14. What do the concentric circles mean on the CORS map?

15. What is the difference between National CORS and Cooperative CORS?

16. What does the name of the directory 1996/044 stand for ? Does 044 represent April 4th ?

17. I plotted the coordinates of a CORS site and it is a long way from the town or city of that name. Why is the name in error?

18. I'm trying to use data from the CORS site BLYT and/or others in Southern California and there is only the observation file (99o). I would like to process my GPS data using this site. Why is the navigation file (99n) missing?

19. I can not access the USCG bulletin board. Has the phone number changed?

20. Should I use the positional coordinates for the L1 phase center or those for the antenna reference point (ARP)?

21. I see that you have a 24 hour file out there for the site that I need, but I only need 1 hour of that data. Is there an easier way to get what I need?

22. What is OPUS and where can I find it?

23. How is the UFCORS different from the way I was retrieving data?

24. On the UFCORS Page there are several ways to compress the data. Can you explain the different methods?

25. On the UFCORS Page I do not know which time zone to select. Do I have to convert to UTC (Universal Time Coordinated)?

26. I have heard that I can improve my results by applying the "precise" orbits? Where can I find these orbits?

27. Why can't I find the site I want in the choice list for UFCORS?

29. What is a coordinate file?

30. Can you explain the benefit of "Interpolation"?

31. Where can I find out more about a site? What kind of receiver/antenna? Who is the responsible agency for that site? Logfile!

32. What are the contents and format of a Met data sheet?

33. I have experienced some trouble retrieving gzip compressed files from your site. I download it but when winzip runs it says it is not in gzip format. Any ideas?

34. I use WINZIP to uncompress your files.  Last year it worked fine but since the new year (2000), my software tells me your data is from a different year like 1970 or 2007.  Any ideas?

35. Can I improve the position I get from my handheld GPS unit?

36. When I post-process GPS phase data with my manufacturer's software, which coordinate should I use for CORS -- the L1 phase center (L1PC) or the Antenna Reference Point (ARP)?"

37. Is there a list of all the nationwide Differential GPS (DGPS) sites, operational, planned and proposed?

38. I think there is a problem with some of the rinex files for several cors stations.  The files seem to have trash in them that is causing many errors in my software.

39. I've noticed that one of your sites has varying coordinates for the base station.  The Rinex file displays one coordinate while the property box in my manufacturer's software displays another with the WGS as a reference frame.  I thought I could find the correct coordinate by visiting the CORS website and looking at the data sheet, but that gives me another coordinate. Which is correct?

40. I am using a Trimble 4800 receiver. I am never able to get OPUS to process my rinex files. I don't know if it is the data itself, the Trimble rinex converter, the receivers or what.

41. We are looking at installing CORS sites around the county and we would like to know about the different ways the antennas can be mounted. We have a variety of places to put them such as on buildings and in open areas. We would like to know if there are any types of standard mounts that we should use.

42. What are the criteria for recomputing CORS coordinates?

43. I noticed that the NGS and IGS precise ephemeris files are now both 15 day latency. Is this a permanent situation? I just wanted to confirm that 8 day files are no longer available.

44. I downloaded one of the precise orbit files (igr13600.sp3.z) from the NGS website and was wondering at the format of the data. The SP3 format link states that the data is either position or velocity, which is indicated by either a "P" or a "V" at the beginning of each line, followed by 4 values. This files has a "PG" at the beginning of each line. I assume that this is position. However, there are 4 integers after the clock bias (or drift for velocity) term. What are these numbers? I was also wondering what the units are when the data is velocity. The SP3 format link gives the units for position data only.

45. Request timed out.  I cannot connect to your ftp server.

46. I see in the directions for filling out a station log that is asks for
Alignment from True N : (deg; + is clockwise/east)
How do I get this information.  I am in Flemington, NJ and my coordinates are
40 30 6 N
74 54 4 W