“The signal that we are concerned with is the open civilian signal. The Americans have adopted an approach towards GPS over the last decade known as ‘regional denial.’ They can distort the accuracy of the civilian GPS signal on a regional basis that is remarkably precise. For instance, they reduce the accuracy of GPS broadcasts over Afghanistan. But keep in mind that what they have done to date — and this is the only thing they have ever shown a willingness to do — is reduce the accuracy. Technically speaking, they increase the circular error of probability. While theoretically they could alter the signals to literally read false positions, they have never done this in the past. But that is the just part of the issue.” Aitan looked at his prime minister for approval to continue.
“We’re listening,” said Eli Cohen.
“The reasons they are unlikely to ever do anything with GPS other than reduce the accuracy from several meters to, say, a hundred meter circular error or so, are many. First, there are so many civilian uses, including aviation, that rely on GPS. Second, there are other systems now available, including the Russian Glonass and commercial systems like Galileo. Glonass is in poor shape right now, but the Russians have budgeted the funds to launch new satellites to return the system to a true global system. Even the Indians have a regional system under development. Just like we do, most modern military GPS receivers can use other networks to check and triangulate against the GPS signals.”
In addition to the prime minister, General Avner was learning more about GPS than he had known. As minister of defense of Israel, he was embarrassed. “Where are the Iranians on this?” he asked.
“Unfortunately, General, they have already embraced this new technology, which is not very sophisticated. The signals are out there and if the receiver has a good internal clock, it is relatively easy to determine which signals are being intentionally degraded, especially if the receiver is moving slowly.”
“What does ‘moving slowly’ mean?” Avner asked.
“In the world of three-dimensional global positioning, slow is an airplane or a bomb in its early phase of free-fall. But a ballistic missile is not slow and despite the existence of multiple space-based positioning signals, the speed of a ballistic missile works against accurate positioning and makes it more than worthwhile to ensure that the Americans degrade the GPS signal, which I am sure they will do when the time comes.”
“Thank you, Yavi,” the minister of defense replied.
“There is more that everyone here should understand,” Aitan continued. “Differential equations can also go a long way to allowing a user to reverse the effects of GPS degradation and return to a high level of accuracy. This is as simple as having a signal being broadcast from a transmitter with a known location on earth. This transmitter is comparing what it is being told by the GPS signals it picks up to its known position and then broadcasting corrective information that is used by another mobile receiver. If you have several of these corrective transmitters broadcasting, you can achieve very high accuracy. We anticipate that Hezbollah and even the Iranians will attempt to use this enhancement if they launch GPS guided weapons at us.”
“What are we doing to defeat this?” The question came from Cohen, who realized that Avner had the same question but was too embarrassed to ask. On his notepad, Zvi Avner made a note to himself to dig into this matter after the meeting.
“We have jamming and spoofing equipment along the Lebanese border and around every major target,” Aitan answered. “More importantly, we will have an EC-130 airborne with high powered jamming and spoofing equipment as well as receivers designed to locate any differential beacons. The IAF would then attack the beacons. Now, if Hezbollah attacks us by surprise, these last couple of steps are tough to get into place quickly. But in the case of Esther, I am sure we will be prepared.” Aitan relaxed and leaned back in his chair, yielding the floor.
Eli Cohen was willing to apologize to his minister of foreign affairs, even if Avner wasn’t. Cohen looked at Avi Gresch. “It’s okay, Avi. This isn’t common knowledge.” Cohen looked at Avner and gave him the type of scolding look that a parent gives to a teenager who is too opinionated at the dinner table. “Zvi, will you take care of establishing the right communication channels with the Americans please. Obviously we need to be sure all of this is properly coordinated for Esther.” Zvi Avner nodded and wrote down a reminder on the notepad in front of him. Cohen turned to Aitan. “Have you covered what you need?” Cohen laughed. “Maybe I should phrase it ‘what we need.’”
“Yes, sir.”
“Good. Zvi, since you were finally getting animated, please continue.”
“Thank you, Prime Minister.” Avner was eager to get back to a topic over which he had mastery. “I have a couple of things to review before we discuss the primary issue for us today. The first item is related to our last discussion on the M-600, as well as all of the other missiles we are facing these days. We are moving towards operational deployment of Iron Dome. During January we successfully tested the system against multiple targets simultaneously. It intercepted three inbound rockets as designed and we now have a unit fully trained for initial deployment. I expect to be operational by year end.
“Rafael is already gearing up missile production and we are lobbying the Americans for emergency funding for more batteries. Each battery will have three twenty tube launchers and initially two reloads on hand for each launcher. So we will have one hundred eighty missiles available for each battery. If we get the funding from the U.S., I expect that we will field five batteries per year in 2011 and 2012.
“Iron Dome is our tactical or point defense system. Arrow 2 is our strategic anti-ballistic missile system and continues to undergo improvements and upgrades. But I am not satisfied with the current range of Arrow 2, so we are working on a longer range intercept missile. We are working with Boeing to develop Arrow 3, which will give us much higher effective altitude capability, including the ability to kill low earth orbit satellites. That said, I have a high degree of confidence that the latest Arrow 2 block 3 version will be capable of intercepting any Persian Shahab-3 missiles fired at us. And of course we have the six Patriot missile batteries in place. All of the Patriots are now upgraded to GEM-T standards and we have a total of 384 missiles on hand. Discussions are underway to bring more Patriot batteries into the country. We also continue development of David’s Sling, which will far exceed the Patriot in range. Although for this group only, some of the recent testing has shown us that issues exist.”
“Give me an honest timetable.” Cohen requested.
Zvi Avner did not want to be on the record regarding this matter. Sophisticated systems which are highly dependent on software development, are never glitch free and never come in on time — and Avner felt that everyone else in this room should understand that reality. “If you are pressing me for a guess, I think the missile is a year behind schedule. I don’t think we can count on deployment before late 2011.”
“We will already have dealt with Iran by then,” Cohen responded.
“We have Arrow 2 in position to handle the primary Persian threats. If you want, we can negotiate to obtain Patriot Pac-3 batteries until David’s Sling is ready.”