Rape Prevention Personal Security System - PSST

PSST was invented and Engineered in 1980

There is a serious rape problem on American campuses and in American cities. Young women are having to experience an extremely traumatic experience far too often. I have heard figures where a co-ed student may have over a 25% chance of being raped during her 4-year college career.

I find that totally unacceptable. I know women that still carry the trauma of having been raped ten years after having been attacked. No one should have to go through that.

A device has been invented for rape prevention and personal safety and security. It is a small necklace, bracelet or other piece of jewelry which contains a tiny switch and a simple and tiny cel-phone-like microwave radio transmitter. If she presses her PSST device, it does not emit any sound so the rapist will not realize that help is coming. Seconds later, a Police Car would arrive! Her UNIQUE signal would send a very brief (just a few millionths of a second transmission) to each of four special receiving antennas and receivers in the University city. The PSST system detects and re-transmits one of those signals, so TWO brief signals arrive at each receiver antenna, only a few billionths of a second apart. That time delay is multiplied by the speed of light to know EXAXCTLY how far the girl was away when she triggered her PSST, WITHIN ONE FOOT. Some advanced mathematical analysis of hyperbolic patterns is then done in our computer, somewhat like the old Loran-C Coastal Navigation System, to determine WHERE SHE IS (X, Y, and Z, within one foot or better) and WHO SHE IS (so Police Officers could identify her instantly).

PSST is VERY inexpensive, and the piece of jewelry she would wear is small and simple to actuate. For college coeds, the transmitter could be rented for less than $5 per month! Within 1/4 of a second of her actuating the device, which is totally silent, the city's Police would know PRECISELY where she was (within about one foot or 1/3 meter!). This new system provides an immense amount of additional personal safety.

(For the record, the public version of the GPS technology is well known to only have an accuracy of around 80 feet or 25 meters, in any direction, so therefore location precision only can identify slightly less than an acre, or a portion of a city block where the girl might be. In addition, for GPS to work, the GPS device must first access at least four orbiting satellites which are each more than 22,000 miles away and then to receive complex data strings from each of them, and then the GPS device generally takes around twenty seconds or longer before processing all that data. This PSST system is therefore FAR BETTER than any GPS device could ever be, in BOTH the amazing location precision and the lightning-fast speed of providing the information to Police.)

This PSST (PerSonal Security Transmitter) system is meant to be so accurate and so quick that the actual benefit is intended once a few attempts were made. Once attackers are stopped by Police near the very start of an attack (where the girl is hopefully still uninjured), and the local news media publicize it, our hope and intention is that potential attackers would be aware of that and not even try! If THEY become convinced that they WILL get caught, and before ever accomplishing their goal, we hope that most potential attackers are smart enough to realize that it is pointless to even try! THAT means PSST would then be the first true RAPE PREVENTION system.

The problem is much broader than just on college campuses. Women of all ages, in virtually all locations, now find it necessary to continually be alert to the possibility of this danger. Many have developed paranoid attitudes as a result of these fears.

Other aspects of modern society also represent potential danger for individuals. Robberies, car-jackings, rage, gang activities, and many other dangers, make all of our lives have some personal danger in them.

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This concept was invented and Engineered in early 1980. This presentation was first placed on the Internet in May 1997.

Many different approaches have been tried to deal with this problem. In general, they have had limited value.

Currently, in my opinion, only MACE-type products and hand-held air-horn or siren-type devices have general benefit for the large numbers of coeds. All of the above are valuable, of course, but there still seems to be a need for additional safety. A MACE type product is really only useful if the young woman HAD ALREADY REALIZED potential danger and already had her hand on the device. That is often not the case in many real situations.

Actually, if I were to consider selling such devices, I might make it a very loud air-horn or siren-type noisemaker which the girl would be expected to THROW on the nearby ground. The impact with the ground would trigger an acceleration sensor inside it to make it start to make noise. The would-be rapist would suddenly have a new complication, that of a very loud noisemaker on the ground. WOULD he continue to try to rape the girl? Knowing that nearby people would certainly LOOK at what was going on? Or would he decide to try to pick up the noisemaker to try to disable or destroy it, in order to be able to continue with his attempt at rape? In any case, the girl MIGHT have a few seconds to try to run away, while the rapist was experiencing brief confusion. Best of all, rather than hurting the girl to try to get such a noisemaker from her, it is lying several feet away from her on the ground!

In addition, with the great increase of handguns, the large amounts of drug use (and purchase), and the frustration of many members of the lower classes with their lot in life, the crime rate in general is increasing at a rapid rate. Getting mugged for a few dollars is becoming far too common. In addition to the co-eds, it would be useful for the general populace to have available an inexpensive personal safety device.

I have invented a VERY inexpensive system to provide a great amount of additional personal safety. I call it the PerSonal Security Transmitter or PSST. It represents a wonderful advance over current approaches to personal safety. It is essentially an "instant locating" system for anyone in distress.

The simplest way to explain the unique operation of this system is with an analogy. Imagine that you are camping near the bottom of a large canyon, which has at least two specific flat areas of canyon walls that make excellent echoes. While you are sleeping, you have a standard tape recorder, with a conventional microphone, running. During the night, in the dark, a valuable meteorite lands SOMEWHERE in the canyon, creating a sound of impact and two distinct echoes off the walls. Your tape recorder therefore has the record of THREE sounds on it. The actual impact will always be the first, as that sound traveled directly from the impact site to the microphone. The other two sounds will be delayed, because those sounds necessarily have to travel longer paths, first from the impact site to the canyon wall and then from that wall to the microphone.

I discovered a mathematical way of analyzing the time separations of those three recorded sounds, to PRECISELY identify the location of the impact sound, probably within one foot of the exact impact location, even though it occurred in pitch blackness! At your leisure the next morning, you can play back the recording and very accurately determine the SEPARATION IN TIME of the three sounds recorded. It is irrelevant as to whatever the exact time of impact actually was. Even the quality of the recorder would not be that critical, regarding how constant its motor moves the recording tape, as the ONLY time intervals that need to be known are only fractions of a second apart. A little calculation and you could walk right to the meteorite! (Actually, with that single microphone and recorder, there is no way of knowing which reflected sound was the first, so there would be two mathematical solutions and therefore two possible actual impact locations. If you also had a second microphone and recorder, in any other location, it would then be easy to know which echo was the first, to eliminate that uncertainty.)

If you want more about this basic concept, we know the speed of sound, around 1100 feet per second, and we know the exact distance between the microphone and the canyon wall that reflected the sound. The time delay on the tape recorder between the actual (direct) sound and such an echo therefore tells us how many extra feet of path there was between the direct path and the (combined) reflected path segments. This is actually a simple mathematical problem which results in a solution that is a hyperbola of points that could possibly be where the source (impact) was. A similar analysis of the actual direct sound and the SECOND echo gives a mathematical solution of a different hyperbola. The meteorite IS lying at the point where the two curves cross! Simple!

Our PSST system essentially enables the Police to do the same, to locate a young woman very quickly and very accurately, generally WITHIN ONE FOOT PRECISION, and in a fraction of a second, after she triggered a simple and inexpensive hand-held (or smaller) transmitter.

A critical aspect of this system is that the sound/signal source is so simple. No advanced electronics of any sort are involved or necessary. The meteorite certainly did NOT contain any electronic devices! All it did was make a simple but sharply defined sound of impact! The PSST device the young woman has only needs to have the most primitive of electronic device, because of this unique method of analysis, which allows using a very simple, inexpensive transmitter.

As to the analysis of the time reception, several years after I invented PSST, I discovered that a standard coastal Marine Navigation system, called Loran-C, has used similar (but backwards!) methods for over forty years. The intersection of hyperbolic curves is a well proven method of position determination.

More information on the Rape prevention PSST System. That discussion presents a small (bicycle-handle-sized or smaller) device that would be RENTED to each coed for less than $5 per month, affordable to any student. The monitoring part of the system recognizes her signal in a tiny fraction of a second, and displays her EXACT location (within about one foot!) ANYWHERE in that city, within 1/4 second of her pressing the device's triggers. In other words, the Police would almost instantly know that she was in need of help, and her name and description would also be displayed on the computer monitor. Squad cars dispatched would know precisely where to look and who to look for. It is realistic that the Police car would arrive within two or three minutes of when she pressed the triggers. The Officers could even call out her name, as though they knew her personally! This should assure that the attacker could not progress very far in his efforts and it should almost guarantee that he will be apprehended.

The system also re-calculates her position every second that she has the transmitter activated. If a perpetrator is dragging her into bushes or has put her in a vehicle, the PSST system would be able to track her movement! With the amazing accuracy of location that PSST has, the system will be able to continuously determine what street such a vehicle was on, which lane it was in, and even how fast it was moving!

The local news media would quickly spread the word that virtually anyone who even TRIED to rape any girl would certainly get caught, without even being able to complete the act. This is actually our central premise, that soon after PSST was operational, most potential attackers wouldn't even try! Our whole goal is that the number of rape ATTEMPTS would drop to near zero! And all this would be for an expense to each student of less than $5 per month or $50 per year!

The PSST system is designed to have a number of safeguards so the system is not subject to a lot of false alarms or regarding lost or stolen transmitters. There would be little sense in installing such a system if the Police soon chose to not follow them up! Descriptions of these features are included in our discussion in the other pages in this site.

Auto thefts are also on the rise. The auto alarms that people install in their vehicles don't seem to even draw any attention any more. Walk down a street of any large city and you'll hear alarms activated but no one even looks or checks them out. An improved alarm system would be useful, especially if it would also help find stolen cars. Some such systems ARE currently available, but they are pretty expensive and they all depend on that city's police cars to be outfitted with very expensive locating equipment. Further information on the PSST-based Vehicle Security Version.

Home security systems and home fire alarms are useful, but their benefits could be increased if the signal was noticed and acted upon right away. Further information on the PSST-based Home Security Version.
Further information on the PSST-based Smoke/Fire Version.

Elderly people are at increased risk of injuries, illnesses and falls. If this should happen when and where they are alone, it might be a great deal of time before help arrives. Some limited systems do exist to alleviate the dangers but they are somewhat expensive and often require the user to stay close to their home or phone. An improved, economical system would be beneficial. Further information on the Elderly Version of PSST.

The PSST System is all of these, and more! There are even some applications that would benefit the Military during training maneuvers and during complex battlefield conditions. Further information on the PSST-based Military Version.

Please Click Here for more comprehensive information on the PSST System. That discussion focuses on the use as a Rape Prevention device, but all the characteristics and operations are the same for the other System applications as well.

A technical presentation provides an explanation of the design and theory on which the PSST System is based and for instructions on creating and installing a PSST installation. For more information yet, please e-mail to the address below.

We consider this to be a Public-Service and the pages of this site contain all the information necessary to design and install the whole rape-prevention and elderly-protection system at no charge. Regarding possible use of the concept for products manufactured for profit, for auto protection, fire safety, home security or the other applications, we would require a contractual agreement. ONLY the rape-prevention and the elderly-protection versions of the PSST invention concept are intended to be offered at no or minimal charge. An exception to this offer applies regarding companies which intend to manufacture and/or market PSST-based rape prevention or elderly protection systems for profit.

I first invented this system in 1980 in Gainesville, Florida, in response to daily television news reports of how many rapes occurred that day on the Campus of the University of Florida. I thought it extremely impressive that the U of F was so open and honest with a problem that all other Colleges pretended did not even exist, so I dedicated myself to trying to help U of F to solve their horrible situation. I found it incredibly depressing to hear about the three or five rapes reported ON THAT DAY. If 1500 rapes occurred on Campus every year, that was around 6,000 in a four-year degree program. I knew that University of Florida then had around 16,000 co-ed students on campus. I quickly calculated that in a four-year College attendance, it implied that more than 30% of those College coeds were likely to be raped. (Years later, other Universities later admitted having similar problems, and it seems universally accepted today that on most major College Campuses in the US, a young woman currently has about a 25% likelihood of being raped before Graduation.) That HAS TO BE considered absolutely unacceptable. How could parents send their daughters to College if they were aware of this horrible situation? Worse, NO ONE ELSE seems to have provided significant methods of providing safety for those millions of young women>

PSST certainly CAN provide that safety, and more! I have attempted many times over the years since 1980 to get the PSST system operational. Sadly, I do not personally have sufficient expertise in microwave electronic circuitry to be able to build the necessary electronic devices, and I have been amazed at how little interest anyone else seems to have about trying to stop such rapes from happening! I put these pages on the Internet in May 1997. In the years after that, at least FORTY different people have contacted me and insisted to me that THEY have the necessary expertise, and most have bragged that they could finalize the design and wire up prototypes "in a few days". Yet, absolutely NONE of them ever have! One man, who presented himself as an absolute expert in such circuitry, told me that he was just too busy to do that, even though he insisted that it would only take him a few days to do. He informed me that he would need me to personally pay him $40,000 PER DAY such that he would re-arrange his schedule to do the needed work. First, I do not happen to HAVE a few hundred thousand dollars lying around to give to him for maybe a week of effort. Second, I considered it outrageously arrogant that he feels that his talents are worth $40,000 per day. And third, I wonder if his attitude will change WHEN a daughter of his happens to get raped!

I do not know if any of those forty people might actually have had the expertise to solve the final (seemingly small) hurdles which are keeping PSST from becoming operational, since none have them have ever even spent a few minutes working on the concept. However, between the long-time successful operation of the Loran-C marine coastal navigation system (which proves the value in the intersection of two hyperbolas approach) and its remarkable similarity to PSST in many ways, AND these many people who insist that they could each have solved the remaining electronics issues "in a few days", I continue to be optimistic that EVENTUALLY someone will step forward to "waste a few days of their infinitely valuable time" to enable hundreds of thousands of young girls to avoid a clearly horrendous experience.

There HAVE BEEN several non-microwave-electronics-experts who have contacted me and wanted to help. In each of those cases, they were extremely optimistic that they fully understood the situation and could provide the needed solutions. But in each of those cases, they were not aware of the strange things that occur at microwave frequencies! In case you are such a person who wants to help, there is an analogy that is useful. You flip a wall light switch when you enter or leave a room, and an incandescent light bulb illuminates the room. From a human perspective, the room becomes lit or dark "immediately or instantly". That is not actually the case! When electricity is sent to that light bulb, it actually takes quite a few milliseconds (thousandths of a second) before the filament heats up and is giving off light. In fact, the room GRADUALLY brightens up, with even the color changing, from a very brief very faint red light through orange and then yellow to what we call white light. Why is this important here? If we ask WHEN did the room light up, the answer SEEMS to be obvious, as being at the INSTANT when we flipped the switch. But if we require a precision of time of the nearest thousandth of a second, this becomes a very difficult question! Do you say that the room is lit when it is fully bright? Or just bright enough to see anything? The easiest answer tends to be the instant when it is HALF-BRIGHT, as that is a time that is fairly easy to determine accurately. Still, there can be some variation of a few milliseconds one way or the other, because the filament does not always heat up the exact same way each time. If we tried to ask, tell me that time to the nearest millionth of a second, the answer is essentially meaningless, because of those variations.

In microwave electronics, when you or any circuit simply closes a switch, it might initially seem that it is an instantaneous event, but that is NOT true! There are very few electronic devices that have a response time of better than around one one-millionth of a second. Yes, for all practical situations, that seems fast enough. But it isn't for PSST. We need to know the time of such events far more accurately than that, on the order of the nearest billionth of a second. So, for traditional circuit components, which take a thousand times that long to turn on or turn off, we have a situation resembling the room light switch.

There ARE some solutions to this. GPS accomplishes it in an immensely complex way, where it creates an EPIC several times, which takes half an hour to describe! Loran-C clearly accomplishes this need as well, but by mathematical analysis. There are also aspects of cel-phone operation and even Police radar guns, where very accurate timing of signals is done. So THERE ARE PEOPLE WHO KNOW HOW TO DO THESE THINGS. I have just never found one who has any interest in trying to prevent rapes from happening!

(The Technical Description page in this site linked above discusses the exact microwave circuitry details that are required.)

In 2007, a new technology called ShotSpotter has started being used in Oakland, California and some other cities. It is NOT the same as PSST, and works on a somewhat different basic concept, but it has some similarities. That ShotSpotter system is designed to have audio microphones installed in many places in a city to listen for the sound of gunshots.

That system operates on AUDIO waves instead of radio waves, so the operation is based on waves traveling at the speed of sound, 1100 feet per second, rather than the PSST's being based on waves traveling at the speed of light, about a million times faster at 1,000,000,000 feet per second. Their system is actually based on the long-used triangulation method of locating a source, but they use aspects that are vaguely similar to aspects of PSST. Specifically, their microphone devices actually contains four separate microphones, spaced a few inches apart in a square (horizontal) array. Each microphone hears the sound of the gunshot at a slightly different time, due to their slightly different distances from the gunshot source. A microprocessor compares those timing differences and is able to determine the approximate DIRECTION of the source. The device also contains a GPS receiver, but NOT for any of the actual GPS capability! It only uses the extreme accuracy of the exact TIME which the GPS satellites provide.

When the calculated directions are compared between different receiver assemblies, the DIRECTION lines tend to cross somewhere, which indicates the approximate location of the gunshot source. When the reception TIME values are then applied, then very accurate DISTANCE values are calculated (but only when several receivers' results are compared). This refines the location to become very accurately known, often within a few feet.

The ShotSpotter technology is NOT actually that similar to PSST, as it is actually based on simple triangulation methods, rather than the more sophisticated hyperbolic analysis of PSST. Still, the inclusion of examining the exact TIMES OF SIGNAL RECEPTION (actually in two different ways!) is an indication that something vaguely similar to PSST has come into existence.

The Loran-C coastal marine navigation system has long been the most similar technology to PSST, except that it uses the method in a reverse or backwards manner! Loran-C is entirely based on the same method of determining hyperbolic solutions to signal reception times and then determining the intersection point of two such hyperbolae. (I was NOT aware of the existence of Loran-C when I invented PSST, and consider the successful operation of Loran-C to be a wonderful proof that PSST will work exactly as I had calculated). However, Loran-C is "backwards" in that a fixed-location transmitter on land creates the initial pulse and also the re-transmitted pulse, and the analysis of the signal reception times is done by the device which is in a specific moving boat (The boat skipper is then able to see where he is on a map, which has hyperbolic curves drawn across it). This is remarkably similar to the PSST method, except for the fact that our INITIAL pulse is generated by the (portable) hand-held PSST device, the repeater is at a fixed location (exactly like Loran-C) and the analysis of the signal reception times is done by receiving devices in fixed locations. (The girl does NOT need to know where she is, but the PSST approach provides the location-analysis result to the fixed system).

Much of the technology of Loran-C therefore seems to be 100% applicable to PSST! However, it appears that Loran-C has become a dinosaur system (due to the arrival of GPS devices) and it appears that there are no longer any technicians who seem to understand the workings of or the circuitry for Loran-C! It seems certain to me that the circuitry that Loran-C uses to generate the initial signal creates a pulse that is well-defined in time, possibly sufficiently to give the accuracy that PSST is capable of, the one-foot location precision. The Loran-C repeater tower is certainly essentially identical to what is needed for PSST. And the Loran-C receiver used in a boat certainly has all the circuitry to accurately determine the DIFFERENCE in the reception times of the signals from the initial and repeated signals, EXACTLY what the PSST receivers need to do.

This all implies to me that PSST should be able to be assembled and operational IN WEEKS, by essentially entirely using surplus Loran-C equipment. However, no one seems to be familiar with any of that technology or that equipment. I suspect that even the CIRCUIT DIAGRAMS of Loran-C transmitters, repeaters and receivers might be all that is needed to get PSST (finally) operational.

This has been immensely frustrating because I do not have the personal expertise in microwave electronics circuitry, and have been unable to find anyone who has such knowledge who seems remotely interested in stopping rapes from occurring!

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C Johnson, Theoretical Physicist, Physics Degree from Univ of Chicago